Effectiveness of Workplace Interventions for Depression in Asia: A Meta-Analysis

Abstract

This meta-analysis is the first study conducted in Asia to quantitatively review the effectiveness of depression interventions in the Asian workplace. We identified 19 controlled intervention studies with a total sample size of 3,325 subjects representing different industry sectors in Mainland China, Hong Kong, Japan, Malaysia, and South Korea. Interventions were coded as Cognitive-Behavioral, Multimodal, Alternative, Organizational, and Strength-Based, which were delivered face-to-face or mediated by a computer or telephone. Overall, the results of a pooled mean effect size (Cohen’s d) of 0.417 (95% confidence interval [CI] = [0.257, 0.576]) revealed a significant and moderate positive effect of workplace interventions on the alleviation of depressive symptoms within the Asian workforce. This effectiveness could justify the increasing organizational need for investing in enhancing workplace mental health, as promoted by the World Health Organization. Moreover, ancillary moderator analyses in this study identified several key factors to further enhance the effectiveness of workplace interventions. Specifically, in addition to conventional cognitive-behavioral interventions, alternative and novel interventions with indigenous components and mediated interventions with interactive elements were found to have practical significance in the Asian workplace.

Keywords

meta-analysis intervention for depression Asia workplace

Introduction

According to the World Health Organization (WHO; 2012), more than 350 million people of all ages suffer from depression globally. It is predicted that depression will be the most burdensome illness in developed countries by 2030. It is indeed one of the most debilitating and costly adult psychiatric illnesses and it has been the leading cause of sickness absences and work incapacity (Henderson, Harvey, Øverland, Mykletun, & Hotopf, 2011; Hilton, Scuffham, Vecchio, & Whiteford, 2010; Jones, Tanigawa, & Weiss, 2003). In fact, the impact of depression on job performance has been estimated to be greater than that of other chronic conditions, such as arthritis, hypertension, back problems, and diabetes (Kessler, Greenberg, Mickelson, Meneades, & Wang, 2001). Moreover, individuals with chronic illness such as diabetes and chronic obstructive pulmonary disease are also more likely to be predisposed to depression (Danna, Graham, Burns, Deschênes, & Schmitz, 2016; Patten et al., 2016; Zhang, Ho, Cheung, Fu, & Mak, 2011). It followed that early interventions become very important in preventing the perpetuation, or even exacerbation, of depression. Given these substantial figures, the close linkage between mental health and work, and the central role of employment in people’s lives (which can occupy almost one third of the lifetime; WHO, 2008), the workplace has been recognized by the Ottawa Charter as an important setting for health-promoting interventions for depression (WHO, 1986).

Workplace Depression: Costs and Impacts

According to the WHO (2010), depression carries the heaviest burden of disability among mental and behavioral disorders. It can lead to decreased productivity and quality of work, increased tardiness or absenteeism, impaired presenteeism, increased turnover rates, a higher risk for workplace accidents, and increased likelihood of substance abuse (Burton, Pransky, Conti, Chen, & Edington, 2004; Henderson et al., 2011; Hilton et al., 2010; Jones et al., 2003). In some cases, it can be severe enough to lead to suicide (Jacobs, 2003).

In the West, it was estimated that 70% of all people diagnosed with major depression were actively employed in the United States (Druss, Rosenheck, & Sledge, 2000; Greenberg et al., 2003; Race & Furnham, 2014). In the East, the adverse impact of depression on the work capacity is no smaller. For instance, an epidemiological study in Mainland China reported a 40.2% workplace depression rate among employees (Yu et al., 2006), which was significantly higher than that in both the United States (6.4%; Kessler, Merikangas, & Wang, 2008) and Europe (33%; McDaid, Curran, & Knapp, 2005). In Hong Kong, a recent cross-sectional study revealed that 25% of respondents who worked in different industries had presented depressive symptoms in the past month (The University of Hong Kong, 2014).

In 2010, Mr. Nagatsuma, the former minister of the Ministry of Health, Labor, and Welfare of Japan, expressed his opinion on the need to increase resources devoted to examining and intervening in depression at the workplace after the launch of the Joint Declaration of Countermeasure for Depression in Japan (Ozaki, 2011). The prevalence of depression was found to be 44.2% among 1,476 Japanese employees in the community (Fushimi, 2015). It has consistently been found that depression strongly affects on-the-job work performance in Japan and the lost productivity was estimated to be, approximately, 28 to 30 lost days per year (Tsuchiya et al., 2012). Meanwhile, in South Korea, the mental health of workers is supported by the National Health Insurance Service (NHIS) and has become a major focus in the field of occupational health management (Cho et al., 2013). Depression has been observed to be prevalent among Korean workers of different occupations and the productivity loss in Korea per person has been estimated to be, approximately, US$680 a month (Lee & Jung, 2008). In Taiwan, nearly 50% of health care practitioners in general hospitals were found to have depressive symptoms in a cross-sectional study (Su, Weng, Tsang, & Wu, 2009), whereas the prevalence of depression in the Malaysian work community was reported to be 10.3% among 1,556 respondents (Maideen, Sidik, Rampal, & Mukhtar, 2014). In Singapore, the indirect cost was 81% and dominated the total costs of managing depressive disorder. Approximately, 50% of indirect costs were associated with loss of productivity and unemployment (Ho, Mak, Chua, Ho, & Mak, 2013).

As reflected by these alarming figures, the costs of not intervening among the depressed workforce could be huge as depression causes substantial functioning limitations at the workplace across different Asian countries and regions.

Exploring the Effectiveness of Different Depression Interventions in the Asian Workplace

Workplace interventions can be generally classified into three main categories—primary, secondary, and tertiary—according to the public health model (Murphy & Sauter, 2003; Quick & Tetrick, 2003). Primary interventions target the entire working population at a worksite through health promotion or education campaigns that are preventive in nature. Secondary interventions focus on people who are at risk for depression and mental illness, while tertiary interventions are typically individual-based treatments that are intended to be therapeutic and curative such as certain Employee Assistance Programs. In practice, workplace interventions could be any of the three categories or any combination of the categories reviewed in this article. The interventions could target individuals or organizations and the essence is to help employees to manage their depression and optimize their job performance.

Individual- versus organizational-level interventions

Individual-level interventions are directed at changing personal characteristics but not the work environment, such as trainings in cognitive-behavioral skills, relaxation, stress coping, depressive symptom management ability, and problem-focused coping skills (Tan, Tang, Ng, Ho, & Ho, 2015). Organizational-level interventions are directed at enhancing the compatibility between the worker and the work environment such as employee participation in decision making. In the West, findings have suggested that organizational-level interventions could be more effective than individual interventions because organizational interventions are transformative through increasing workers’ participation in fostering organizational changes (Nelson & Prilleltensky, 2010; Richardson & Rothstein, 2008). In practical terms, workplace intervention at the organizational level is identified as more preferable than individual-level intervention as it seems to be more preventive, sustainable, and fundamental in its approach (Karasek, 1992). Seeing the positive findings in the West and considering the cultural context in the East, which is more collectivistic in nature (Cheng, Tsui, & Lam, 2015), we hypothesized that organizational-level interventions would have a significant effect—and possibly an even stronger effect than individual-level interventions—on helping depressed members of the Asian workforce. This is hypothesized because employees have a stronger organizational identity and responsiveness to organizational practices in Asia than in the West (Hofstede, 1984; Huff & Kelley, 2003).

Conventional versus novel interventions

In the vast array of common workplace interventions for depression, which range from primary to tertiary and involve different levels, some types of programs are deemed more conventional and popular at worksites, such as cognitive-behavioral interventions, relaxation therapy, and stress management programs with a mix of different therapeutic components (Cuijpers, Smit, & Van Straten, 2007; Van der Klink, Blonk, Schene, & Van Dijk, 2001). According to previous research findings from Western work settings, conventional interventions that consist of cognitive and behavioral components, such as cognitive-behavioral therapy (CBT), tended to yield better results than those with only behavioral components, such as relaxation therapy (Cuijpers et al., 2007; Ruotsalainen, Serra, Marine, & Verbeek, 2008; Van der Klink et al., 2001). Nevertheless, for some popular multimodal stress management programs that weaved in more therapeutic components and evolved into a hybrid of CBT and relaxation therapy, the effectiveness was found to be equivocal as the assumption of “the more the better” was not evident (Biding & Nordin, 2014; Kawaharada et al., 2009; Mino, Babazono, Tsuda, & Yasuda, 2006). Such programs might also demand more individual and organizational resources, such as time and effort. As such, we predicted that conventional CBT would be effective in alleviating depression in the Asian workplace and consistent with Western findings. However, we also predicted that multimodal stress management programs with a mix of therapeutic components might not be as effective as CBT, despite its popularity. In Asia, depression interventions need to be culturally adapted because Asians suffering from depression have unique clinical features including maladaptive ruminations (Lu et al., 2014) and health beliefs (Ng et al., 2008).

Apart from the conventional interventions, there is a trend of developing alternative and novel workplace programs to manage mental health issues in a cost-effective and indigenous way for different populations and cultures. In particular, the use of computer-mediated interventions (Imamura et al., 2015; Kojima et al., 2010), the transition from the traditional “fixing-what-is-wrong” to a “strength-based” approach (Cheng, Kogan, & Chio, 2012; Cheng et al., 2015), and the integration of novel and alternative treatment components (Pan, 2009; Song & Lindquist, 2015; Tsang et al., 2015) are the three new directions of carrying out workplace interventions.

Computer-mediated interventions

Computer-mediated interventions are becoming more popular in work settings because they can be provided consistently to a large number of employees. Moreover, the interventions appear more acceptable and are regarded as less stigmatizing in comparison with formal face-to-face interventions (Kojima et al., 2010; Phillips et al., 2014). In the past decade, several reports have cited the efficacy of website-based CBT training, suggesting its efficacy in improving mild depression or anxiety (Kaltenthaler et al., 2006). The National Institute for Clinical Excellence (NICE; 2006) has also approved several computerized cognitive-behavioral therapy (cCBT) packages for low-intensity psychological interventions. Nevertheless, computerized self-help-style interventions, including the use of CD-ROM or one-way websites, were speculated to be insufficient due to relatively low program participation and commitment (Clarke et al., 2005). It followed that newer forms of computer-mediated interventions, such as email interventions (Kojima et al., 2010), Internet programs (Imamura et al., 2014), and smartphone-based therapy (Bakker, Kazantzis, Rickwood, & Rickard, 2016; Zhang, Ho, Cassin, Hawa, & Sockalingam, 2015), were designed to be more interactive in nature. For mediated interventions, some organizations also made use of the medium of telephone to deliver manualized CBT to their employees in a relatively efficient and interactive manner (Furukawa et al., 2012). Despite the increasing popularity of computer- or technology-mediated interventions, the evidence of their effectiveness has been inclusive, albeit promising (Foroushani, Schneider, & Assareh, 2011; Kaltenthaler et al., 2008). As such, it is worth investigating the difference between traditional face-to-face intervention and mediated intervention and examining the possible moderating effect of the medium of delivery. We hypothesized that mediated interventions with interactive components that could resemble conventional face-to-face cognitive-behavioral interventions would be significantly effective.

Strength-based, positive psychology interventions

Strength-based interventions stem from the positive psychology approach and offer a less stigmatized way to promote mental health in the workplace. The rationale for strength-based, positive psychology interventions is to nurture the strengths or positive traits of employees, thereby buffering the negative effects of stressors and improving their mental health status (Seligman, Steen, Park, & Peterson, 2005). Unlike the traditional “fixing-what-is-wrong” approach, strength-based interventions aim to strengthen the psychological capital of employees (Luthans, Youssef, & Avolio, 2007). Indeed, previous studies among both the general population (Seligman et al., 2005) and the working population in the West (Chan, 2011; Hartfiel, Havenhand, Khalsa, Clarke, & Krayer, 2011) demonstrated that positive psychology interventions are effective in promoting subjective well-being, with an effect size of 0.3 (Bolier et al., 2013). Seeing its particular relevance and applicability to work settings, further understanding the effectiveness of strength-based interventions in comparison with the traditional “fixing-what-is-wrong” treatments would provide important insights for the development of less-stigmatizing interventions. We predicted that the application of strength-based interventions would have a consistent positive effect on the Asian workforce due to the nature of the universal virtue of employees worldwide.

Alternative and novel interventions

In addition to the changes in the medium of delivery and orientation in approach, alternative interventions that integrate novel treatment components have been developed in a more contemporary and indigenous way (Pan, 2009; Song & Lindquist, 2015; Tsang et al., 2015). For example, the rise of mindfulness practices, which have potential beneficial effects in treating depression and anxiety, has led to the proliferation of mindfulness interventions in the workplace (Chen, Yang, Wang, & Zhang, 2013; Dobkin & Zhao, 2011; Kabat-Zinn, 2009; Warnecke, Quinn, Ogden, Towle, & Nelson, 2011). Apart from mindfulness, the Chinese workplace has also attempted to weave cultural components into interventions. For instance, the traditional Chinese therapeutic massage of acupressure and qigong exercises were combined with CBT as a workplace intervention (Tsang et al., 2015). The integration of Daoist philosophy in CBT was also in place for some Chinese organizations as an alternative intervention (Pan, 2009). In addition, novel treatment components (e.g., exercising, dieting) have also increased in popularity (Ikenouchi-Sugita et al., 2013; Yoshikawa, Nishi, & Matsuoka, 2015). We hypothesized that these alternative interventions with indigenous and novel components that can be easily weaved into the Asian culture and contemporary organizational settings would offer significant and unique therapeutic benefits to the Asian workforce in comparison with the conventional approaches developed in the West.

Significance of the Present Study

Acknowledging that workplace depression has been predicted to be an important health challenge with significant costs for organizations in both the East and the West, and that the workplace is potentially an important location for depression intervention, a number of researchers have asserted that further research effort is required to identify the best practices for addressing employee depression (Czabała, Charzyńska, & Mroziak, 2011; Krupa, 2007; Race & Furnham, 2014). Practically, increasing our understanding of effective workplace interventions and our awareness of potential moderators could constitute a remarkable contribution to health economics at both individual and societal levels. Depression has surpassed cardiovascular disease and cancer to become the leading contributor to global disease burden and work incapacity (Collins et al., 2011). Suicide is a major concern among Japanese workers with depression. In Japan, marital status and absence of stress reduction techniques were significant independent risk factors for suicidal ideation among Japanese workers with depression (Sugawara et al., 2013). In South Korea, high emotional demand with low job control is related to suicidal ideation among Korean workers (Yoon, Jeung, & Chang, 2016). Therefore, it is urgent to develop more effective interventions. As such, the present study serves the instrumental value of providing readily accessible information to help organizations plan and implement their workplace interventions.

Empirically, relative to studies and reviews of interventions for workplace depression in the West, little research has been performed to examine and compare different interventions for depressed members of the workforce in Asia (Furlan et al., 2012; Martin, Sanderson, & Cocker, 2009; Tan et al., 2014). There was only one systematic review, conducted by Furlan and her colleagues, on workplace depression and intervention; it consisted of 12 Western studies published between 1997 and 2010. A meta-analysis conducted by Tan and her team that consisted of six Western studies and three Asian studies published between 1980 and January 2013 was found to be the only meta-analysis on workplace interventions with an Asian component (Tan et al., 2014). The insights obtained from these two studies were limited and inconclusive due to the restricted processing of qualitative data in a systematic review and the small number of studies included. Consequently, our meta-analysis aimed to fill in the blank by bringing in new insights on identifying and enhancing the effectiveness of various workplace interventions. Specifically, we investigated the potential moderators of the type of intervention (individual or organizational, conventional or novel) and the medium of delivery (face-to-face or mediated intervention) to demonstrate differential effects. To the best of our knowledge, this is the first meta-analysis to focus on workplace interventions for depression in Asia with consideration of both the practical and empirical significance.

Method

Literature Search

Studies that assessed the effectiveness of depression interventions and were workplace based or work directed in their setting or approach for the working population in Asia were collected from a variety of sources. In this study, depression was broadly defined (ranging from depressive symptoms to the feelings associated with it) and measured by validated instruments because people who are clinically or subclinically depressed might not admit it, for personal reasons.

To avoid publication bias (Rothstein & Bushman, 2012), a comprehensive literature search that involved both computer and manual literature searches was conducted. Relevant published and unpublished works, including journal articles, book chapters, theses and dissertations, working papers, and conference papers, were located, with a time frame of 1985 to December 2015. The computer search involved five databases: PsycINFO, Medline, Embase, Social Science Citation Index, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Several of these databases include both published and unpublished studies. The computer searches were conducted with the same strings of keywords: “(Workplace or occupation or work or job or employee or employment) AND (Depression) AND (Intervention or management or health promotion) AND (Asia or China or Japan or Korea or Hong Kong or Singapore or Shanghai or Asian or Chinese or Malaysia)” were used in the computer search. These electronic searches yielded 1,556 articles (PsycINFO = 526, Medline = 548, Embase = 199, Social Sciences Citation Index = 250, and CINAHL = 33).

In parallel, a manual search was conducted by reviewing the reference lists from selected articles and book chapters to identify additional citations beyond the electronic search, which yielded three more articles. Researchers active in the field of workplace mental health were also contacted for working papers and recommendations regarding unpublished studies. Moreover, our searches identified several relevant articles that did not report sufficient information for the calculation of effect sizes; the authors were contacted for the relevant information.

Inclusion Criteria

Studies had to meet certain criteria to be included in this meta-analysis. First, their sample had to comprise men and women of working age (usually 18-65 years old) who were employed in an organization in an Asian country or region. Second, they needed to evaluate interventions or programs that were workplace based or that could be explicitly implemented and/or facilitated by employers. The definition of a workplace or work setting is any location where an employee performs his or her assigned work. In addition, only studies with a comparison/control group were included, which could include randomized controlled studies or nonrandomized studies. Third, the selected studies had to use established and validated measures of depressive symptoms as their outcome measures. Fourth, the studies had to report the sample size, means, and standard deviations for both the treatment and comparison/control groups. If the means and standard deviations were not reported, other types of statistics that could be converted into a standardized effect size were required. Moreover, only studies written in English or Chinese were included. Studies that did not meet all of the above inclusion criteria were excluded.

Coding Scheme

There were two coders for this study: the first author of this article and an assistant professor in the field of clinical psychology. The following information was extracted and coded from the selected studies:

Type of intervention and relevant treatment components: CBT, multimodal, strength-based, alternative, or organizational intervention, and the relevant treatment components.

Medium of delivery: Face-to-face or mediated (computer-mediated or telephone-mediated) delivery of intervention.

Sample characteristics: Country/region (e.g., Hong Kong Special Administrative Region [SAR], Mainland China, Japan, Korea, Malaysia), industry sector (e.g., health care, education, manufacturing, service, general), and job description of employees (e.g., teachers, health care practitioners, hotel employees).

Sample size: Sample size of both treatment group and comparison group (waiting list group, no treatment group, or treatment-as-usual group).

Outcome measure: The self-reported depression scale used for measuring depressive symptoms (e.g., Depression, Anxiety, and Stress Scale–21 items [DASS-21], Center for Epidemiologic Studies–Depression Scale [CES-D], Beck Depression Inventory–II [BDI-II], Zung Self-Rating Depression Scale [SDS], Brief Job Stress Questionnaire [BJSQ]).

Study design: Randomized controlled trial (RCT) or nonrandomized control trial (non-RCT).

The initial rate of agreement on the coding between the coders was 91% and discrepancies were resolved by discussions between them.

Meta-Analytic Procedures

The statistical analyses were performed using Comprehensive Meta-Analysis Version 3 software. The standardized mean difference (Cohen, 1992; Lipsey & Wilson, 2001) was calculated to represent the intervention effects reported in the eligible studies. This effect size statistic is defined as the difference between the treatment and control group means on an outcome variable divided by their pooled standard deviations. For this meta-analysis, the random-effects model was adopted and decided a priori as heterogeneity was expected due to the variety of intervention types across country/region and industry (Hunter, Schmidt, & Judiesch, 1990; Schmidt & Hunter, 2014). Under the random-effects model, studies are assumed to have their own study-specific effects. The observed effect size is a combination of the study-specific effect and the sampling error (Cheung, Ho, Lim, & Mak, 2012). The results of the random-effects model are conservative in that their 95% CIs are often broad, thus reducing the likelihood of Type II errors.

The presence of heterogeneity was tested by the I² statistic. The I² value is a percentage that indicates study-to-study dispersion due to real differences, over and above random sampling error. A value of 0% represents an absence of dispersion and larger values indicate increasing levels of heterogeneity. An I² value of 25% can be considered a low, 50% a moderate, and 75% a high level of heterogeneity, which suggests the presence of potential moderators (Higgins, Thompson, Deeks, & Altman, 2003).

Due to the hypothesized high level of heterogeneity, subgroup analyses were performed to identify moderators by testing for differences in Cohen’s d between the subgroups. Two major potential moderators of the “type of intervention” and the “medium of delivery” were determined according to the research relevance. In parallel, the potential moderating effect of “country/region,” “sector of industry,” and “study design (RCT or non-RCT)” were also explored according to the characteristics of the investigated studies.

Publication Bias Analysis

To address the possibility of publication bias due to the tendency to submit or publish studies based on the strength or direction of the results (Dickersin, 1990), three indicators were used: funnel plots (Kepes, Banks, McDaniel, & Whetzel, 2012), Orwin’s fail-safe number (Orwin, 1983), and Egger’s regression intercept (Egger, Smith, Schneider, & Minder, 1997). A funnel plot is a graph of the effect size against the study size. When publication bias is absent, the observed studies are expected to be distributed symmetrically around the pooled effect size. Orwin’s fail-safe number indicates the number of nonsignificant unpublished studies needed to reduce the overall significant effect to a nonsignificant effect. The effect size can be considered robust if the number of studies required to reduce the overall effect size to a nonsignificant level exceeds 5 × K + 10, where K is the number of studies included. Moreover, a nonsignificant p value in Egger’s regression intercept can also indicate a robust effect size.

Results

Description of Studies

The literature selection process is illustrated in Figure 1. First, 1,556 titles were retrieved from databases and three titles were identified through reviewing the reference lists from selected articles. After 160 duplicated articles were removed, 1,399 articles were screened. Then, 1,305 articles were excluded based on their title and abstract and 94 articles were identified as being potentially eligible for inclusion. Among these 94 articles, 19 studies described in 18 articles met the inclusion criteria and were included in this study. The remaining 76 articles were excluded for various reasons, which are illustrated in Figure 1.

Figure 1.

Flow diagram of study selection.

The studies evaluated 3,325 subjects of whom 1,821 were in intervention groups and 1,504 were in control groups. The characteristics of the studies, including the “type of intervention,” “medium of delivery,” “country/region,” “sector of industry,” and “study design” are found in Table 1.

Table 1.

Characteristics of the Studies Included in the Meta-Analysis.

Author(s), year	Country/region, industry, description	Design	Sample size	Type of intervention	Delivery	Intervention	Treatment components	Treatment duration	Control intervention	Outcome measure
Biding and Nordin (2014)	Malaysia, Service, Hotel employees	Non-RCT	T = 68 C = 58	Multimodal	Face-to-face	Stress management intervention program	Cognitive-behavioral skills, relaxation exercises, communication and interpersonal skills training, EQ at work, goal setting	3 sessions	TAU (2-hr seminar on stress awareness)	Depression: DASS-21
Cheng et al. (2012, Study 1)	Hong Kong SAR, General, Working adults	RCT	T = 54 C = 54	Strength-based	Face-to-face	Coping flexibility intervention	Coping flexibility skills	6 sessions	Waiting list	Depression: CES-D
Cheng et al. (2012, Study 2)	Hong Kong SAR, General, Working adults	RCT	T = 53 C = 54	CBT	Face-to-face	Cognitive-behavioral intervention	Cognitive-behavioral skills	6 sessions	Waiting list	Depression: CES-D
Cheng, Tsui, and Lam (2015)	Hong Kong SAR, Health care, Health care practitioners	RCT	T = 34 C = 34	Strength-based	Face-to-face	Gratitude intervention	Write gratitude diaries about work-related events twice a week	4 weeks	No treatment	Depression: CES-D
Chu et al. (2013)	Shenzhen (Mainland China), Manufacturing, Floating workers	RCT	T = 188 C = 72	Multimodal	Face-to-face	Comprehensive mental health intervention	Psychoeducation, coping skills training, communication and conflict resolution	6 months	No treatment	Depression: BDI
Furukawa et al. (2012)	Japan, Manufacturing, Full-time employees	RCT	T = 58 C = 60	CBT	Telephone mediated	Telephone CBT (tCBT)	Manualized CBT program administered via telephone	8 sessions	TAU (employee assistance program)	Depression: BDI-II
Ikenouchi-Sugita et al. (2013)	Japan, General, Working adults	Non-RCT	T = 455 C = 151	Alternative	Face-to-face	Walking intervention	30 min of walking per day for 4 weeks for workers who did not have exercise habit	4 weeks	No treatment	Depression: SDS
Imamura et al. (2014)	Japan, General, Working adults	RCT	T = 270 C = 336	CBT	Computer-mediated	Internet-based CBT (iCBT) in manga format (Japanese comic story)	Cognitive-behavioral skills in manga format	6 sessions	TAU (received email with 500-word simple stress management tips)	Depression: BDI-II
Kawaharada et al. (2009)	Japan, Government, Civil servants	Non-RCT	T = 65 C = 63	Multimodal	Face-to-face	Stress inoculation training	Psychoeducation, cognitive-behavioral skills, relaxation training and practice	3 sessions	Waiting list	Depression: subscale of BJSQ
Kawakami, Araki, Kawashima, Masumoto, and Hayashi (1997)	Japan, Service (electricity supply), Blue-collar workers	Non-RCT	T = 79 C = 108	Organizational	Face-to-face	Stress reduction program oriented toward the work environment	Job redesign and action planning in group to improve the work environment for stress coping	1 year	No treatment	Depression: SDS
Kojima et al. (2010)	Japan, Manufacturing, White-collar office workers	RCT	T = 137 C = 124	CBT	Computer-mediated	CBT using brief email sessions	Cognitive-behavioral skills	4 sessions (1 group session and 3 email sessions)	Waiting list	Depression: CES-D
Leung, Chiang, Chui, Mak, and Wong (2011)	Hong Kong, Education, Secondary school teachers	Non-RCT	T = 70 C = 54	CBT	Face-to-face	Brief cognitive-behavioral stress management program	Cognitive-behavioral skills	3 sessions	Waiting list	Depression: DASS-21
Mino, Babazono, Tsuda, and Yasuda (2006)	Japan, Manufacturing, Office workers	RCT	T = 21 C = 30	Multimodal	Face-to-face	Stress management program	Cognitive-behavioral skills, relaxation, and email counseling for stress management	2 sessions with email follow-up counseling in 3 months	No treatment	Depression: CES-D
Pan (2009)	Shanghai, Real estate, Employees	RCT	T = 32 C = 35	Alternative	Face-to-face	Daoist cognitive therapy combined with acupoint massotherapy	Cognitive-behavioral skills integrated with Daoist philosophy, acupuncture, and massage of acupoint	4 weeks	No treatment	Depression: SCL-90
Shimazu Okada, Sakamoto, and Miura (2003)	Japan, Education, Teachers	Non-RCT	T = 8 C = 8	Multimodal	Face-to-face	Stress management program	Stress inoculation training, cognitive-behavioral skills, relaxation training	5 sessions	Waiting list	Depression: BJSQ
Song and Lindquist (2015)	South Korea, Health care, Nursing trainees	RCT	T = 21 C = 23	Alternative	Face-to-face	MBSR	Yoga, sitting, walking, breath-work, body scan, eating meditation	8 sessions	Waiting list	Depression: DASS-21
Tsang et al. (2015)	Hong Kong, Education, Elementary school teachers	Non-RCT	T = 47 C = 46	Alternative	Face-to-face	Combined CBT and complementary and alternative medicine	Cognitive-behavioral skills, self-management, relaxation techniques, mindful exercises, aromatherapy and acupressure	6 sessions	Waiting list	Depression: DASS-21
Tsutsumi, Nagami, Yoshikawa, Kogi, and Kawakami (2009)	Japan, Health care, Nurses	RCT	T = 28 C = 40	Organizational	Face-to-face	Participatory intervention for workplace improvement	Active employee participation to develop and implement work goals and action plans by job redesign and improvement of psychosocial work environment	9 months	No treatment	Depression: GHQ
Uchiyama et al. (2013)	Japan, Manufacturing, Blue-collar workers	RCT	T = 133 C = 154	Organizational	Face-to-face	Participatory intervention to improve psychosocial work environment	Active employee participation to develop and implement action plans to improve the psychosocial work environment	6 months	Waiting list	Depression: CES-D

Note. RCT = randomized controlled trial; BDI = Beck Depression Inventory; SAR = Special Administrative Region; EQ = emotional intelligence; TAU = treatment as usual; DASS-21 = Depression, Anxiety, and Stress Scale–21 items; CES-D = Center for Epidemiologic Studies–Depression Scale; CBT = cognitive-behavioral therapy; SDS = Zung Self-Rating Depression Scale; BDI-II = Beck Depression Inventory–II; BJSQ = Brief Job Stress Questionnaire; MBSR = mindfulness-based stress reduction; GHQ = General Health Questionnaire; SCL-90 = Symptom Checklist.

Effects of Workplace Interventions for Depression Compared With Control Conditions

Figure 2 presents the posttest effects of workplace interventions for the 19 studies included in this meta-analysis and the pooled mean effect size using a random-effects model.

Figure 2.

Posttest effects of workplace interventions for depression in the Asia workplace.

According to Cohen, effect sizes of 0.2, 0.5, and 0.8 are small, moderate, and large, respectively (Cohen, 1992). In this study, the pooled mean effect size between the intervention and control groups indicated by the standard difference in means (Cohen’s d) was 0.417 (95% CI = [0.257, 0.576], p < .0001), which showed a moderate and statistically significant effect of workplace intervention for depression among the Asian working population. Heterogeneity was considerable in view of the high I² value of 76.69%, which suggested the potential presence of moderators for the intervention effects on workplace depression. Effect sizes ranged from 0.011 (Uchiyama et al., 2013) to 1.369 (Cheng et al., 2012) within the 19 studies.

Moderator Analyses

Moderator analyses were performed by the subgroup analyses given the suggested heterogeneity and the results are presented in Table 2. The two major moderators of the “type of intervention” and “medium of delivery” were examined, while we also investigated the possible moderating effect of the study design, country/region, and industry sector.

Table 2.

Moderator Effects: Subgroup Analysis (Posttest).

Moderator	Subgroup (study)	k	n	Cohen’s d (95% CI)	p
Type of intervention	Alternative	4	810	0.420 [0.221, 0.620]	<.000*
	Cognitive-behavioral	5	1,216	0.344 [0.112, 0.576]	.004*
	Multimodal	5	581	0.377 [−0.045, 0.799]	.080
	Organizational	3	542	0.137 [−0.138, 0.412]	.328
	Strength-based	2	176	0.937 [0.075, 1.800]	.033*
Medium of delivery	Face-to-face	16	2,340	0.472 [0.276, 0.668]	<.000*
Medium of delivery	Mediated	3	985	0.176 [0.050, 0.301]	.006*
Country/region	Hong Kong SAR	5	500	0.727 [0.380,1.074]	<.000*
	Japan	10	2,328	0.172 [0.081, 0.263]	<.000*
	Mainland China	2	327	0.883 [0.637, 1.129]	<.000*
	Korea	1	44	0.715 [0.105, 1.325]	.022*
	Malaysia	1	126	0.249 [−0.103, 0.600]	.166
Industry	General	4	1,427	0.617 [0.175, 1.060]	.006*
	Health care	3	180	0.579 [0.279, 0.879]	.000*
	Education	3	233	0.436 [0.175, 0.697]	.001*
	Manufacturing	5	977	0.355 [−0.001, 0.712]	.051
	Service	2	313	0.120 [−0.104, 0.344]	.294
	Government	1	128	0.028 [−0.318, 0.375]	.873
	Real estate	1	67	0.667 [0.174, 1.159]	.008*
Study design	RCT	12	2,045	0.529 [0.287, 0.771]	<.000*
Study design	Non-RCT	7	1,280	0.240 [0.120, 0.360]	<.000*

Note. k = number of studies; n = sample size; CI = confidence interval; SAR = Special Administrative Region; RCT = randomized controlled trial; non-RCT = nonrandomized control trial.

p < .05.

Type of intervention

For the subgroup analysis on the intervention type, only the subgroups alternative intervention (k = 4), cognitive-behavioral intervention (k = 5), multimodal intervention (k = 5), and organizational intervention (k = 3) were examined. The remaining subgroup, strength-based intervention (k = 2), was excluded because it consisted of only two studies and thus was too small for the moderator analysis. Among the different types of interventions, a statistically significant intervention effect was found for alternative intervention and cognitive-behavioral intervention. However, no significant effect was found for multimodal intervention and organizational intervention.

Specifically, a small to moderate effect size was found for both the alternative intervention (Cohen’s d = 0.420, 95% CI = [0.221, 0.620]) and the cognitive-behavioral intervention (Cohen’s d = 0.344, 95% CI = [0.112, 0.576]). This indicated the significant moderating effect of the type of intervention in which the alternative intervention and cognitive-behavioral intervention were found to be effective in the Asian workplace, whereas the multimodal intervention and organizational intervention were not.

In addition, although strength-based intervention was not contrasted with other types of interventions due to the small number of studies involved, the preliminary effect size generated from the two included studies was large and significant (Cohen’s d = 0.937, 95% CI = [0.075, 1.800]), which calls for attention.

Medium of delivery

For the subgroup analysis of the medium of delivery, the subgroup face-to-face intervention (k = 16) and mediated intervention (k = 3) yielded statistically significant intervention effects. A small to moderate effect size was found in the subgroup face-to-face intervention (Cohen’s d = 0.472, 95% CI = [0.276, 0.668]), while a small effect size was found in the subgroup mediated intervention (Cohen’s d = 0.176, 95% CI = [0.050, 0.301]). Nevertheless, the substantial overlapping of the CIs between these two groups indicated no statistically significant difference in their intervention effect. This finding implied that the medium of delivery was not a significant moderator and that workplace interventions were of comparable effectiveness regardless of the medium of delivery.

Other Moderating Effects

Country/region

For the subgroup, analysis of country/region, only the subgroups Hong Kong (k = 5) and Japan (k = 10) were investigated and they yielded a statistically significant effect of depression intervention among their working population. A moderate to large effect size (Cohen’s d = 0.727, 95% CI = [0.380, 1.074]) was observed in the Hong Kong subgroup, while a small effect size (Cohen’s d = 0.172, 95% CI = [0.081, 0.263]) was observed in the Japan subgroup. Specifically, as the CIs of the two groups did not overlap with one another, a statistically significant difference in the intervention effect between the Hong Kong and Japan populations was suggested. As such, it indicated that country/region was a significant moderator in which workplace interventions were significantly more effective for treating depression at the workplace in Hong Kong than in Japan.

Industry sector

For the subgroup analysis of industry, only the subgroups general (k = 4), health care (k = 3), education (k = 3), and manufacturing (k = 5) were examined. The results revealed that the workplace intervention effect was statistically significant for the general, health care, and education industries but statistically nonsignificant for the manufacturing industry. Specifically, a moderate effect size was found in the general subgroup (Cohen’s d = 0.617, 95% CI = [0.175, 1.060]) and the health care subgroup (Cohen’s d = 0.579, 95% CI = [0.279, 0.879]), while a small to moderate effect size was observed in the education subgroup (Cohen’s d = 0.436, 95% CI = [0.175, 0.697]). As such, industry was found to have a significant moderating effect on workplace interventions for depression; the interventions were effective for the general, health care, and education industries but not for the manufacturing industry in this study.

Study design

For the subgroup analysis of study design, both the randomized controlled trial (RCT) group (k = 12) and the nonrandomized controlled trial (non-RCT) group (k = 7) showed a statistically significant intervention effect on the depressed workforce. A moderate effect size (Cohen’s d = 0.529, 95% CI = [0.287, 0.771]) was observed in the RCT subgroup, while a small effect size (Cohen’s d = 0.240, 95% CI = [0.120, 0.360]) was observed in the non-RCT subgroup. Due to the substantial overlapping of CIs between the two groups, the difference in the intervention effect between the RCT group and the non-RCT group was indicated to be statistically nonsignificant. As such, no significant moderating effect was found in the study design and the mix of RCT and non-RCT studies in the current meta-analysis was allowed.

Analyses of Publication Bias

The possibility of publication bias was addressed by inspecting the funnel plot (Kepes et al., 2012), Orwin’s fail-safe number (Orwin, 1983), and Egger’s regression intercept (Egger et al., 1997). The funnel plot is presented in Figure 3. It looked symmetrical with the 19 studies included; however, because it could be subjective and difficult to determine the presence of asymmetry by inspecting only the funnel plot, other indicators of publication bias were also examined.

Figure 3.

Funnel plot for analysis of publication bias.

Orwin’s fail-safe number was computed and found to be 449, which indicated that 449 studies would be required to reduce the overall effect size to a nonsignificant level. Moreover, a nonsignificant p value of .0631 (two-tailed) in Egger’s regression intercept was generated. Both indicators suggested that publication bias was unlikely in this study and that the pooled effect size was found to be robust.

Discussion

This is the first meta-analysis to synthesize studies on the effectiveness of depression interventions in the Asian workplace. Overall, the results revealed that workplace interventions produced a significant and moderate positive effect for reducing depressive symptoms in the Asian workforce across countries/regions and industries. This indicated effectiveness could justify the increasing organizational need to invest in enhancing workplace mental health, as promoted by the WHO. Nevertheless, the overall analysis may provide a look at the surface as there was significant heterogeneity within the studies. As such, subgroup analyses are deemed necessary to determine the moderators and offer a deeper understanding of the potential variability of intervention effects across situations.

In the moderator analyses, by dividing the studies into relatively homogeneous subgroups based on their type of intervention, medium of delivery, and other characteristics (study design, country/region, and industry sector of industry), three significant moderating effects—type of intervention, country/region, and industry sector—were found. The differences in the medium of delivery and study design did not yield significant moderating effects.

Types of Interventions: Conventional Versus Novel Interventions

Examining the moderating effect of different types of interventions revealed that cognitive-behavioral interventions and alternative interventions yielded significant and small to moderate intervention effects for the Asian workplace, as we hypothesized. Moreover, multimodal interventions were found to be nonsignificant in effectiveness, as we also predicted. However, the effectiveness of organizational interventions was unexpectedly nonsignificant.

In fact, the significant effect of cognitive-behavioral interventions as a workplace intervention was consistent with the findings of the only previous meta-analysis to mix six Western and three Asian studies on universal interventions (Tan et al., 2014). Specifically, the components of cognitive-behavioral interventions, such as changing thoughts and associated feelings in an adaptive way, were deemed proactive responses to workplace stress and it was found that cognitive-behavioral skills could be easily coached in a structured and systematic way in a work setting. Cognitive-behavioral skills could modify maladaptive ruminations (Lu et al., 2014) and health beliefs (Ng et al., 2008) that are common in Asians with depression. These could possibly account for the significant effect of cognitive-behavioral interventions on workplace depression in Asia. Furthermore, cognitive-behavioral skills might enhance emotional support and introduce positive plans that are protective factors against suicide among Asians (Mak, Ho, Chua, & Ho, 2015).

In parallel, the significant effect of alternative interventions could imply the importance of novel and indigenous treatment components for alleviating depression among the Asian working population. In this meta-analysis, the treatment components of the alternative interventions consisted of daily walking and exercise for Japanese workers (Ikenouchi-Sugita et al., 2013), Daoist cognitive therapy with acupoint massotherapy for Chinese workers (Pan, 2009), mindfulness-based intervention with yoga, body scans, mindful eating, and walking for South Korean workers (Song & Lindquist, 2015), and complementary and alternative medicine with relaxation and mindful exercises for Hong Kong workers (Tsang et al., 2015). All of these alternative interventions demonstrated some cultural adaptation and easy integration into the workers’ lives and cultural contexts. In fact, the development of workplace interventions through alternative and integrated approaches could facilitate mental health promotion at a system level while considering the cultural context (Lerner et al., 2012). The current findings support these initiatives.

As expected, multimodal interventions were found to be ineffective in this meta-analysis. The multimodal interventions included in this study consisted of more treatment components than cognitive-behavioral interventions through the addition of relaxation exercises, communication, and other efficacy trainings. It followed that the nonsignificant effect could imply more treatment components that were not associated with a stronger intervention effect. The bundling of treatment components could even impede the intervention effectiveness. This finding contradicted a previous narrative review that concluded “the most positive results were obtained with a combination of two or more techniques” for workplace interventions (Murphy, 1996). It is speculated that the composition of more treatment components would complicate workplace interventions and demand more individual and organization resources in practice. While organizational researchers might be tempted to institute a combination of treatments in hopes of producing more effective intervention programs, employees could be resistant and stressed regarding the time and effort required. As such, simpler interventions that are likely to be more cost-effective and practical to implement are suggested as additional components in multimodal interventions may decrease and work to the detriment of more complex individual components.

Types of Interventions: Individual- Versus Organizational-Level Interventions

In contrast to our hypothesis, the finding of nonsignificant organizational interventions may be explained by the narrowness of participatory interventions examined by the studies included in this meta-analysis. The participatory interventions were focused on active employee participation in goal setting and action planning to improve the psychosocial work environment, which may represent only one of the many organizational interventions for enhancing workplace mental health. According to the organizational development approach (Secker & Membrey, 2003), there is a variety of organizational interventions that range from specific work scheduling, job allocation, supportive working relationships, and staff management policies to workplace culture. As such, the participatory interventions investigated in this research comprised only a small part of the broad category of organizational interventions; the nonsignificant finding was inconclusive and should not be interpreted as evidence against the development of organizational-level interventions.

Apart from the significant and nonsignificant findings regarding the moderating effect of intervention type, the strength-based interventions that were not counted in the moderator analysis due to the small number of sample studies also deserves some attention. Different from the traditional “fixing-what-is-wrong” approach, strength-based interventions focus on developing the internal strengths and resources of employees to cope with depression and other mental health issues, such as coping flexibility (Cheng et al., 2012) and gratitude (Cheng et al., 2015). These initiatives are aligned with the approach of positive psychology and are perceived to be more acceptable and less stigmatizing by the working population (Bolier et al., 2013; Luthans et al., 2007; Seligman et al., 2005). Therefore, the preliminary significant and large effect size based on the two strength-based interventions included in this meta-analysis suggests a direction in which to explore the effectiveness of strength-based workplace interventions. This may help increase the uptake of similar positive psychology interventions in Asian and global workplaces in the future.

Medium of Delivery

Remarkably, the medium of delivery did not yield a significant moderating effect of the workplace interventions. This finding suggested that face-to-face mediums and mediated mediums by telephone or computer could be equally effective for delivering interventions; thus, this finding provides important research and practical implications. For research, the current findings could offer a piece of evidence regarding the controversy surrounding the use of computer-mediated cognitive-behavioral interventions, which involve significantly reduced human interaction and elements (Green & Iverson, 2009). For practical significance, the indicated effectiveness of mediated mediums may enable organizations to implement their workplace interventions in a much more cost-effective and efficient way that places less burden on manpower. Nevertheless, the results have to be interpreted with caution as the mediated medium included in this research had substantial interactive components, such as email communication (Kojima et al., 2010) and telephone consultation (Furukawa et al., 2012), for implementation.

Differential Effect in Different Asian Countries/Regions and Industries

The findings offer implications regarding the implementation of different workplace interventions for depression in different industries and countries/regions. Regarding the contrasts of countries and regions, the significant intervention effect found in both Hong Kong and Japan could indicate the value of workplace interventions for these two places, which have been famous for their stressful work life. Notably, the significant difference in the magnitude of the effect suggested that workplace interventions were more effective in Hong Kong than in Japan. This might be because Hong Kong employees are more receptive to workplace interventions, the interventions were designed and carried out more effectively in Hong Kong, or for other underlying reasons worth exploring further.

For the comparisons among different industries, the significant intervention effect found in the health care and education sectors provided support to maintain and reinforce the mental health interventions for these work settings, which have long been regarded as demanding and taxing on psychological resources (Boyle, Borg, Falzon, & Baglioni, 1995; Fahrenkopf et al., 2008; Jin, Yeung, Tang, & Low, 2008). However, the significant intervention effect found in the general sector of the working population should be interpreted with caution as it encompassed working adults from unspecified different sectors in the included studies. In addition to the significant effects revealed in the health care and education sectors, the nonsignificant intervention effect found in the manufacturing sector was also noteworthy. It suggested the possibility that commonly used workplace interventions might not work well for manufacturing workers and the possible interfering factors compromising the intervention effect should be investigated. In fact, the relatively routine job tasks and the higher proportion of blue-collar workers might differentiate manufacturing employees from those in the health care and education industries included in this analysis. Previous research has proposed and supported changes in job design and work environment at the organizational level for stress reduction among manufacturing employees, rather than solely psychological interventions at an individual level (Karasek, 1992; Kawakami, Araki, Kawashima, Masumoto, & Hayashi, 1997; Wall & Clegg, 1981). It was also possible that manufacturing workers would manifest their improved mental condition more easily through work performance and related outcomes, such as increased productivity and reduced sick leave (Kawakami et al., 1997), instead of alleviating depressive symptoms.

Strengths and Limitations

This meta-analysis is a pioneering attempt to examine the effectiveness of different workplace interventions for depression in the Asian workplace and to investigate the potential moderators that facilitate the identification of best practices across settings. Given the prevalence of depression in the workplace and the costs associated with impaired work performance, even a small effect size with economic benefits may be regarded as relevant to employers and employees. The strength of this very first meta-analysis in Asia, which cast a wide net to examine different types of interventions in different countries, regions, and industries with indications of their effect sizes, thus provides key information for identifying best practices and increasing generalizability to real organizational settings. In particular, the findings of the significant intervention effect of cognitive-behavioral interventions and alternative interventions, with stronger effects revealed in some countries, regions, and industries, can serve as readily accessible information to help organizations plan and structure their interventions. Moreover, the trends of the mediated delivery of interventions and strength-based interventions, as discussed in this study, might also provide some directions for further exploration.

Certainly, this study has some limitations that should be addressed. Practically, the restricted focus on psychological outcomes of depression is acknowledged. This is an information gap when employers want to obtain empirical information on targeted interventions that improve work-related outcomes in addition to psychological outcomes, such as reducing absenteeism, productivity loss at work, and return on investment. Accordingly, future research should conduct meta-analyses taking work-related outcomes into consideration.

Methodologically, the moderators examined in this study could be confounded by the type of participants in each study and with one another. Our pooled effect size was an average of several heterogeneous effects, which might have been produced by the differences in the characteristics of the sample participants within subgroups. Despite the research attempts to classify the included studies into the most meaningful subgroups, there is a limitation: Subgrouping leads to an inevitable decrease in power and precision. Moreover, as only 19 studies were included in accordance with the inclusion criteria, disaggregating the data into subgroups produced a small number of studies in each cell. This could have led to statistical bias, so the findings should be interpreted with caution.

Conclusion

Depression in the workplace is a complex and perplexing issue that has remarkable consequences for workers and their families, colleagues, supervisors, organizations, government, and society. The present study provided overall support to workplace interventions in the Asian workplace, but it indicated that no single intervention approach was shown to be most effective due to the varying contexts and moderators considered. The current meta-analysis provides some directions for future research and practice regarding various workplace interventions for different industries in different Asian countries and regions, possibly using different delivery mediums.

Footnotes

Acknowledgements

The authors would like to acknowledge Dr. Harry Hui (The University of Hong Kong), Dr. Grand Cheng (Duke-NUS Medical School, Singapore), and Dr. Dannii Yeung (City University of Hong Kong) for their encouragement and support that made this research possible.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Author Biographies

Rebecca W. M. Lau is one of the two registered psychologists in Hong Kong with recognized qualifications and experiences in both clinical psychology and industrial-organizational psychology. She endeavors to integrate her specialties of clinical psychology and industrial-organizational psychology to promote and enhance workplace mental health, with focuses on treating depression and anxiety in the Asian workplace.

W. H. Mak is practicing in family medicine and also an honorary clinical assistant professor in the Department of Family Medicine of the University of Hong Kong.

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