Sage Journals: Discover world-class research

Abstract

Background

Comorbidities among mental disorders can have long-term impacts on children’s development and mental health. There is little robust data about the prevalence of comorbidities in preschool-aged children. The aim was to identify the prevalence of comorbidities among mental disorders in a cohort of 3–4-year-old children in Australia.

Methods

Women were recruited to the Australian Mercy Pregnancy Emotional Wellbeing Study at <20 weeks’ gestation. Mental disorders were assessed among their children at 3- to 4-years old using the Preschool Age Psychiatric Assessment (PAPA). Prevalence of comorbidities is reported.

Results

Almost half (48%) of the children (n = 545) met criteria for mental disorders captured by the PAPA; 43% had anxiety disorders. Of children with at least one diagnosis, 44% had another mental disorder; this represents 21% of the whole sample. Depressive disorders occurred only alongside other disorders, both anxiety disorders and externalising disorders. At least one anxiety disorder was present in more than half of children with specific externalising disorders.

Conclusions

Comorbidity of mental disorders among preschool-aged children is relatively common. Preschool children presenting with mental health symptoms may benefit from assessment protocols which consider multiple mental health disorders, and integrated services to address these.

Plain Language Summary

Mental disorders in young children can have a long-term impact on their health and development, especially if children experience more than one mental disorder at the same time. This is known as “comorbidity”. We aimed to investigate the prevalence and nature of comorbidities among a cohort of preschool-aged children in Australia, in order to inform better mental health assessment of and treatment for children in this age range. The sample consisted of 3- and 4-year-old children (n=545) of women from a longitudinal pregnancy cohort study in Australia. They were assessed for mental disorders using the Preschool Age Psychiatric Assessment (PAPA), administered via a telephone interview with their mothers. More than one in five children (21%) in our sample had two or more diagnoses of mental disorders according to the PAPA. Among children with at least one PAPA mental disorder, 44% had at least one additional mental disorder. At least one anxiety disorder was present in more than half of children with attention deficit/hyperactivity disorder (ADHD), conduct disorder, oppositional defiant disorder (ODD) and depression. Thus, comorbidities did not always fit within externalising or internalising dimensions. Clinicians assessing mental health in preschool-aged children should assess for multiple disorders across both externalising and internalising dimensions. Integrated mental health services are required to address comorbidities in these early years.

Keywords

child mental disorders child psychiatric disorders preschool psychopathology comorbidity PAPA

Introduction

Mental disorders among preschool-aged children can have negative effects on their development and mental health across the lifespan (Angold & Egger, 2007). Early identification of and intervention for mental disorders prior to the commencement of formal education is recommended to prevent poor educational, occupational and health (physical and mental) outcomes (Center on the Developing Child, 2010; Weitzman and Wegner, 2015).

In research and even clinical settings the presence of symptoms of poor mental health among preschool-aged children is commonly assessed by parent completion of a dimensional measure (Achenbach & Edelbrock, 1981; Whalen et al., 2017); scores are typically compared with population norms, to indicate whether these symptoms are within a ‘clinical range’ indexing the likely presence of internalising (problems within the self) and externalising (conflict with the external environment) disorders (Achenbach & Edelbrock, 1981; Whalen et al., 2017). In contrast, few studies report on the prevalence of mental disorders in preschool children using structured diagnostic interviews with parents, which overcome the possible bias of parental proxy reporting via rigorous structured questions which yield diagnoses consistent with the Diagnostic and Statistical Manual of Mental Disorders, DSM-5 (American Psychiatric Association, 2013).

The prevalence of mental disorders among children has been reported in systematic reviews; however these either include broad age ranges from age 4 to 18 (Barican et al., 2022) or focus on specific populations such as children attending primary care (Charach et al., 2020). A relatively recent systematic review and meta-analysis included more than 18,000 children 1 to 7 years old (Vasileva et al., 2021); this review included only studies in which children’s mental disorders were assessed using structured interviews with parents. The overall pooled prevalence of any mental disorder among children aged 1 to 7 years old was estimated at 20.1% (95% CI [15.7, 25.4]) (Vasileva et al., 2021). Among the ten included studies, only three reported on mental disorders among preschool-aged children in settings that can be considered representative of the overall population: children attending required vaccination appointments in Iraq (n = 829, age 12–48 months, mean 30 months) (Al-Jawadi & Abdul-Rhman, 2007), children attending required community health check appointments in Norway (n = 2,475, 46–63 months, mean 53 months) (Wichstrøm et al., 2012), and children recruited through commercial mailing lists in the USA (n = 541, 36–50 months, mean 43.2 months) (Bufferd et al., 2011). Of these, only two (Bufferd et al., 2011; Wichstrøm et al., 2012) utilised the Preschool Age Psychiatric Assessment (PAPA) (Egger et al., 1999) for diagnosis of mental disorders; the third study reporting on mental disorders among preschool-aged children in community settings reported using interviews based on a standardised questionnaire including diagnostic criteria taken from the DSM-IV (Al-Jawadi & Abdul-Rhman, 2007). Based on the PAPA, Bufferd et al. (2011) reported a substantially higher overall prevalence of mental disorders (27%) than Wichstrøm et al. (2012) (6%).

Vasileva et al. (2021) estimated that comorbidity, namely the presence of more than one disorder, occurred in 6.4% (95% CI [1.3, 54.0]) of children 1 to 7 years old; approximately a third of children with one diagnosis of a disorder met criteria for at least one other disorder (Vasileva et al., 2021). The authors reported considerable heterogeneity among the included studies (Vasileva et al., 2021). In the above-mentioned US study (Bufferd et al., 2011), 9% of children had two or more diagnoses; 34% of those with one diagnosis met criteria for multiple diagnostic categories (Bufferd et al., 2011). In the Norwegian study (Wichstrøm et al., 2012), overall prevalence of comorbidities was not reported. However, the odds of attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder, anxiety disorder and depression were significantly higher among those diagnosed with other disorders, compared to those without (Wichstrøm et al., 2012).

In summary, there is substantial heterogeneity among studies reporting on prevalence of mental disorders among children, with regard to the age range of children assessed, measurement of mental disorders, study location and design, and populations targeted (Barican et al., 2022; Charach et al., 2020; Vasileva et al., 2021). The overall prevalences of mental disorders and comorbidities among preschool-aged children are difficult to identify from the current literature; only two studies have assessed mental disorders in community samples by diagnostic interviews such as the PAPA (Bufferd et al., 2011; Wichstrøm et al., 2012); these two studies, conducted in Norway and the US, were published more than a decade ago. The aim of this study was to describe childhood mental disorders and comorbidities among a cohort of 3- to 4-year-old children in Australia, using the PAPA.

Methods

Study Design

Data from the Mercy Pregnancy Emotional Wellbeing Study cohort are used for this study. Further details about this study can be found in the cohort profile paper (Galbally et al., 2017). Women completed Wave 1 data collection at recruitment at up to 20 weeks’ gestation; they were subsequently followed up at up to 28 weeks’ gestation (Wave 2); subsequent data about both the mothers and their children were collected at six months postpartum (Wave 4), 12 months postpartum (Wave 5) and when their children were 3 to 4 years old (Wave 6). At birth, information was captured from hospital records but not from women themselves (Wave 3). Data from Wave 6 (child age 3–4 years) are included in this paper. Sample characteristics are drawn from Wave 1 (<20 weeks’ gestation) and Wave 3 (birth) data.

Recruitment

As described (Galbally et al., 2017), recruitment took place at metropolitan maternity hospitals in Melbourne, Victoria and Perth, Western Australia, as well as regional and rural hospitals in Western Australia. This was a selected cohort design, in which women formally diagnosed with current depression using the Structured Clinical Interview for DSM-IV (SCID-IV) (Carter et al., 2010) were deliberately over-recruited, as well as a group of non-depressed pregnant women.

Women were eligible to participate if they were less than 20 weeks’ gestation and proficient in English. Exclusion criteria were psychotic or substance abuse disorders, child protection involvement, intellectual disability, serious physical illness or psychiatric illness requiring current acute inpatient admission.

Measures

Child mental disorder: The primary outcome was a diagnostic classification of one or more mental disorder among 3–4-year-old children according to DSM-5 criteria (American Psychiatric Association, 2013), and assessed by the Preschool Age Psychiatric Assessment (PAPA) (Egger et al., 1999). The PAPA is a semi-structured research diagnostic instrument that measures psychiatric symptoms and disorders according to the DSM-5, for pre-school age children, aged 2-5. The e-measures electronic version of the PAPA was administered through interviews with mothers of 3-4 years old within MPEWS. The research team undertook training with the authorised trainers of this instrument from Duke University, Developmental Epidemiology (Egger & Angold, 2006), which included coding practice and checking coding with trainers. Following the initial training, subsequent interview administrators underwent a month of training with experienced interviewers who had been trained in the original training with PAPA developers. To facilitate inter-rater reliability, the novice interviewers also completed the coding of at least three interviews after training whilst under supervision with experienced interviewers before completing coding on their own. To ensure quality control, protocol fidelity and consistency for the duration of the data collection, regular supervision with experienced trainers was offered fortnightly to administrators, in which coding queries were discussed with other novice and experienced interviewers.

In the PAPA, compulsory questions are asked about whether symptoms have been present or absent in the past 3 months. If an item is endorsed, the parent is asked follow-up questions, such as onset, frequency, duration and severity of symptoms, and impairment, and to give examples of the behaviour. These behavioural examples provide critical information which guide the interviewer to formally code the PAPA in e-measures. Subsequently an algorithm is applied to determine diagnosis based on coded data. The PAPA has been validated as a reliable standardized measure of DSM-4 psychiatric symptoms and disorders in pre-schoolers (Egger et al., 2006). Its test-retest reliability is comparable to widely used and well-established measures for older children and adults (Egger et al., 2006).

For the purposes of this study, we include the following DSM-5 diagnoses measured using the PAPA: anxiety disorders (separation anxiety, social anxiety, specific phobia, agoraphobia, panic attacks and generalised anxiety disorder (GAD)); post-traumatic stress disorder (PTSD); depressive disorders (including major depression, dysthymia, and/or other specified depressive disorders); attention-deficit/hyperactivity disorder (ADHD), conduct disorder and oppositional defiant disorder (ODD).

As women with a current depressive episode within the past two years were over-represented in this study, we report on the number and proportion of women who met these criteria, as assessed using Modules A and D of the SCID-IV-TR, Clinician Version (First et al., 1997).

Statistical Methods

This is a descriptive study, presenting data on prevalence and patterns of mental disorders and comorbidities in our sample of 3–4-year-old children. Data were analysed using IBM SPSS Statistics version 29.

To evaluate attrition bias, data on sociodemographic characteristics and depression status at <20 weeks’ gestation were compared between women who completed the PAPA (at child age 3–4 years) with women who did not. For binary variables such as depression status, Χ² tests were used, applying the continuity correction. For maternal age, which was not normally distributed, a Mann-Whitney U test was applied.

We report the proportion of children who met DSM-5 criteria for each disorder, and for two or more disorders, according to the PAPA. As a sensitivity analysis we compare the prevalence of two or more mental disorders among children of women who had a current depressive episode at < 20 weeks, and children of women who did not.

Patterns of comorbid mental disorders were first explored by examining the proportion of children diagnosed with each mental disorder, and then their comorbidity patterns with another disorder. For example, we report the proportion of children with a diagnosis of ADHD who also had an additional diagnosis of each other disorder. We demonstrate the degree of comorbidity using a heatmap, generated within Excel using an algorithm to group the data into 6 colour categories; green shades represent lower proportions while red shades indicate higher proportions.

Secondly, we report the odds ratios (OR) and confidence intervals associated with having a specific mental disorder, for each other disorder. Owing to multiple comparisons (approximately 70) and the associated risk of Type I errors, we apply a Bonferroni correction and report only odds ratios with statistical significance <0.001. The only other PAPA-based studies to calculate odds ratios for combinations of mental disorders among preschool children (Bufferd et al., 2011; Wichstrøm et al., 2012) report substantial odds ratios of 5 and above. To detect a more modest odds ratio (OR) of about 2.0 with 80-90% power at a 5% significance level, one requires approximately 16 cases and 16 controls (Lemeshow et al., 1988). Thus, we did not calculate odds ratios within any groups for which exposure (in this case the other mental disorder) did not occur in at least 16 cases.

Ethics

The study has been approved by the Mercy Health Research Ethics Committee (Victoria, R08/22, 3 July 2012) and the South Metropolitan Health Service Human Research Ethics Committee (Western Australia, 2016-192, 11 October 2016). Each woman provided written consent to participate at each wave of data collection. If PAPA interview participants became distressed, the interview was suspended or paused, and the interviewer provided options to abort or reschedule the interview. Information on available supports for women was provided on the Participant Information and Consent form at each wave of data collection, and interviewers discussed these with women as appropriate. Women were also offered a telephone call with a psychiatrist from the research team if they would like to discuss support options. Interviewers offered all women a letter to their child’s general practitioner, psychologist, paediatrician or psychiatrist summarising the results of the research interview. If women indicated they would like this to occur, we obtained written consent from them along with the practitioner’s mailing address.

Results

Eight hundred and eighty-seven women were recruited. Of these, 545 completed the PAPA when their children were 3–4 years of age (Wave 6); among them 95 women (17.4%) had a diagnosis of depression at recruitment. There was no difference between women who completed and did not complete the PAPA on depression diagnosis at < 20 weeks (See Table 1). However, women who were retained in the study (completing the PAPA at Wave 6) were significantly older, and more likely to have a university education and employment at Wave 1 and to be expecting their first (versus second or subsequent) baby than those lost to follow-up (Table 1).

Table 1.

Sample Sociodemographic Characteristics for Women Who did Versus did Not Complete the PAPA at Wave 6

	Lost to follow-up	Completed PAPA at wave 6	χ2,p-value^b
	n (%^a) = 342	n (%^a) = 545	χ2,p-value^b
Culturally and linguistically diverse^c	33 (10.4)	49 (9.3)	0.194, 0.659
Nulliparous	209 (61.5)	375 (68.8)	4.700, 0.030
University education	161 (50.8)	351 (66.2)	19.133, <0.001
Full-time part-time and casual employment	237 (79.3)	457 (88.1)	10.723, 0.001
Married, de facto, or otherwise stable relationship	287 (97.6)	503 (97.3)	0.003, 0.959
Maternal diagnosis of depression at wave 1	69 (20.2)	95 (17.4)	0.876, 0.349

	Median, IQR	Median, IQR	z (Mann-Whitney),p-value
Maternal age at recruitment	31.16, 6.80	33.00, 5.87	5.087, <0.001

^aTotals vary owing to missing data at Wave 1.

^bBold values indicate statistically significant differences when continuity correction applied, p < 0.05.

^cCALD status was indicated using recommended multiple-indicator approach: being born overseas and speaking a primary language other than English (Pham et al., 2021).

The mean (standard deviation) age of the children assessed with the PAPA in months was 43.2 (6.1); the median age was 41.3. The prevalence of each PAPA child diagnosis is presented in Table 2. Notably, 31% met criteria for specific phobias. To explore whether specific phobias disproportionately inflated the overall prevalence, we re-evaluated the overall prevalence after removing specific phobias. Without specific phobia, the overall prevalence was reduced from 48% to 32% (not shown in table).

Table 2.

Mental Disorders at 3-4 years (n (%))

	Overall (n = 545)
Any diagnosis	261 (47.9)
ADHD	41 (7.5)
Oppositional defiant disorder	35 (6.4)
Conduct disorder	20 (3.7)
Depressive disorder (n, %)	13 (2.4)
Any anxiety disorder	232 (42.6)
Social phobia	64 (11.7)
Separation anxiety	61 (11.2)
Generalised anxiety disorder, GAD	42 (7.7)
Agoraphobia	16 (2.9)
Panic attacks	4 (0.7)
PTSD	0
Specific phobia	171 (31.4)
≥2 diagnoses	115 (21.1)
Number of diagnoses
1	146 (26.8)
2	63 (11.6)
3	29 (5.3)
4	11 (2.0)
5	9 (1.7)
6	2 (0.4)
7	1 (0.2)

About half of all children (47.9%) had at least one diagnosis. Of those with at least one diagnosis, 115 (44.1%) had two or more mental disorder diagnoses; this represents 21.1% of the whole sample (Table 2). There was a significant difference between the proportion of children with two or more diagnoses among mothers with and without a diagnosis of depression at Wave 1 (30.5% versus 19.1%, p = 0.019), but not after removal of specific phobias (17.9% versus 11.6%, p = 0.129).

The percentage of children with each additional disorder, within each category of disorder, is shown in Table 3. For example, within the group of children with ADHD, 24.4% of children also had ODD. All children with depression and agoraphobia had at least one comorbid mental disorder. A high proportion of children with ADHD (75.6%), conduct disorder (80.0%) and GAD (85.7%) also had other mental disorder diagnoses.

Table 3.

Prevalence of Specific Comorbidities

Among children with ADHD, ODD, conduct disorder and depressive disorder, between 60% and 77% of each group of children also had at least one anxiety disorder. At least half of the children with ADHD (51.2%) and those with conduct disorder (50.0%) also had specific phobias. Within the anxiety disorders, more than half of the children with social phobia (53.1%), separation anxiety (54.1%), GAD (57.1%) and agoraphobia (68.8%) also had specific phobias.

Table 4 shows the odds ratios (CIs) of each diagnosis associated with each of the other diagnoses, where p < 0.001. Owing to the small number of children with depression and panic attacks, we excluded these mental disorders from this analysis. Many of the odds ratios were statistically significant, but the size of the associations varied greatly. Compared to children without social phobia, the odds of agoraphobia among those with social phobia (and vice versa) were relatively high at 19.76 (6.61-59.04), though the CI range was very wide. The association between ODD and ADHD was also relatively high at 6.18 (2.73-14.01).

Table 4.

Odds Ratios (95% Confidence Intervals) of Each Other Diagnosis Given Each Diagnosis, Where p < 0.001 (Excluding Depressive Disorders and Panic Attacks)

	ADHD	ODD	Conduct disorder	Any anxiety disorder	Social phobia	Separation anxiety	GAD	Agoraphobia	Specific phobia
ADHD	-	6.18 (2.73-14.01)	NS	3.58 (1.79-7.19)	NS	5.04 (2.47-10.27)	4.76 (2.14-10.56)	NS	NS
ODD	6.18 (2.73-14.01)	-	NS	NS	NS	4.91 (2.30-10.47)	NS	NS	NS
Conduct disorder	NS	NS	-	NS	NS	NS	NS	NS	NS
Any anxiety disorder	3.58 (1.79-7.19)	NS	NS	-	-	-	-	-	-
Social phobia	NS	NS	NS	-	-	4.88 (2.63-9.05)	NS	19.76 (6.61-59.04)	2.84 (1.67-4.82)
Separation anxiety	5.04 (2.47-10.27)	4.91 (2.30-10.47)	NS	-	4.88 (2.63-9.05)	-	4.25 (2.07-8.72)	NS	2.95 (1.72-5.06)
GAD	4.76 (2.14-10.56)	NS	NS	-	NS	4.25 (2.07-8.72)	-	NS	3.22 (1.70-6.11)
Agoraphobia	NS	NS	NS	-	19.76 (6.61-59.04)	2.95 (1.72-5.06)	NS	-	NS
Specific phobia	NS	NS	NS	-	2.84 (1.67-4.82)	2.95 (1.72-5.06)	3.22 (1.70-6.11)	NS	-

NS: not significant at p < 0.001.

Consistent with the fact that that all children with depressive disorder and all those with agoraphobia had other mental disorders, these disorders were associated with much higher odds of several other mental disorders.

Discussion

The aim of this study was to describe mental disorders and comorbidities among a cohort of 3- to 4-year-old children, using the PAPA interview. We found that almost half (48%) of the children in this study met criteria for at least one PAPA diagnosis, and 21% had two or more diagnoses. Of those with one diagnosis, 44% had two or more diagnoses.

To our knowledge, this is the first study in Australia to report on mental disorders and comorbidities among preschool-aged children, using the PAPA. This is also the first study to use the PAPA among a non-clinical sample in this age group in more than a decade, at a time when a substantial increase in the prevalence of mental health problems among children and adolescents is being labelled a ‘youth mental health crisis’ (McGorry et al., 2025). The prevalence of disorders among preschool-aged children in our study (48%) is substantially higher than previously reported in two international studies which used the PAPA more than a decade ago. In Norway, the prevalence was reported to be 6% (2012) while in the USA it was 27% (2011). The children in our study were a similar age to those in the USA study (mean age for both studies 43 months), which is younger than the mean age for the study in Norway (mean 53 months). The high prevalence of mental disorders in our sample could be ascribed to the much larger proportion (31%) with specific phobias in our study compared to the prevalence of specific phobias in the USA study (9%) (2011) and the Norwegian study (1%) (2012), both of which also assessed mental disorders using the PAPA. Without specific phobias the overall prevalence in our findings would have been reduced to 32%. Specific phobias are the most prevalent anxiety disorder among children and adolescents and as such, can often inflate overall prevalence estimates (Rapee et al., 2023). Fear responses to scenarios such as the dark, storms, dentists and doctors may be considered normal in pre-schoolers at low frequencies (Egger et al., 2006); these may be relatively transient compared to other disorders.

The overall prevalence of comorbidity (meeting criteria for two or more diagnoses according to the PAPA) in our sample was 21%. Another PAPA-based study among a non-clinical sample reported the prevalence of comorbidity at 9% (Bufferd et al., 2011). In our study, depressive disorders and agoraphobia occurred only with other disorders, not on their own. The highest association was observed between social phobia and agoraphobia. Although specific anxiety disorders commonly occurred with other anxiety disorders this was not exclusively the case.

In this study, we found no significant difference in prevalence of comorbidities among children of women with depression early in pregnancy and those without, when we excluded specific phobias. This is surprising given the association between antenatal maternal distress and adverse socioemotional outcomes among children (Rogers et al., 2020); however, the authors of this review and meta-analysis suggest that the use of self-report measures to assess maternal mental health and child outcomes limits the interpretation of the findings. More research is needed to investigate associations between antenatal depression and comorbidities among preschool-aged child mental disorders, with both maternal and depression and child disorders assessed with diagnostic interviews rather than self-report measures.

Strengths and Limitations

This study adds to a small group of studies (Bufferd et al., 2011; Wichstrøm et al., 2012) reporting prevalence of mental disorders and comorbidities among preschool-aged children, using the PAPA structured interviews with parents (Egger et al., 2006, 2019).

We acknowledge several limitations. The PAPA, while widely used and demonstrating high test-retest reliability among preschool children, was adapted from the parent version of the Child and Adolescent Psychiatric Assessment (CAPA) (Angold et al., 1995); other assessments are available that were developed specifically for this age group (In-Albon et al., 2020). Ours was a selected cohort study, not recruited for the purpose of reporting prevalence and hence without the specific methodological requirements for a prevalence study. Mothers with depression diagnosed early in pregnancy are over-represented due to the recruitment strategy and therefore this is not a community sample where generalisable prevalence data can be ascertained. Overreporting of children’s psychiatric symptoms has been reported among depressed mothers (Müller et al., 2011, 2014). We did not assess maternal depression with structured interviews at child age 3–4. Although we took steps to improve statistical power (excluding small groups from odds ratio calculations) and corrected for multiple comparisons, we advise readers to interpret Table 4 with caution owing to some very wide confidence intervals. Given the deliberate over-sampling of women with depression in our longitudinal cohort, the relatively high level of tertiary education, and the fact that only 62% of women recruited during pregnancy completed the PAPA when their children were 3–4 years old, we recommend that this finding be confirmed with a large, more representative sample, controlling for relevant pregnancy and early childhood environmental factors.

Further limitations may include that we administered the PAPA via telephone interview and not face to face as originally recommended by the authors of the PAPA (Egger & Angold, 2004). Information bias leading to false positives may arise from telephone interviewing. Although other studies report telephone interviews for the PAPA (Bufferd et al., 2011; Danzig et al., 2013; Hattangadi et al., 2024), reliability for telephone-based administration is lacking. Owing to limited resources, we were unable to implement double coding of the PAPA interviews beyond the initial training period of novice interviewers; inter-rater reliability can therefore not be reported Our study was a cross-sectional assessment of the children; future research to report on the trajectory and stability of disorders and comorbidities is recommended. It is not known how impairment associated with multiple diagnoses compares with that associated with single diagnoses; a nuanced assessment of impairment for both groups of children could address this in future research. In addition, we collected data only from mothers; it would be preferable to have multiple sources of data and future studies should collect data from fathers or other informants, to reduce informant bias (Bufferd et al., 2011).

The PAPA is a reliable diagnostic instrument for the preschool population. The high prevalence ascertained in our study may arise due to the robustness of this instrument compared with other studies which utilised parent-reported rating scales. However, the high prevalence may also be the result of over-pathologisation of normative responses, such as fear, which is a normative developmental phenomenon among preschool-aged children. As mentioned, the PAPA was adapted from the CAPA; diagnostic criteria for older children have therefore been applied to a younger age group. In addition, we have noted methodological limitations including non-representative sampling, informant bias and information bias arising from telephone interviewing. Our findings should therefore be treated as preliminary and with caution, awaiting replication by other studies in Australia or similar settings that utilise research-based semi-structured diagnostic interviews such as the PAPA. Longitudinal studies would illuminate homo- and heterotypic trajectories in children in non-clinical samples; among a clinical sample of children from preschool to primary school age, heterotypic development was relatively common, especially in the presence of maternal mental disorders (Jobs et al., 2019).

Alternatively, rather than the result of measurement or cohort effects, the high prevalence could be attributable to the preschool developmental window – a developmental vulnerability window which needs to be managed with care. As such, a “preschool-limited vulnerability” contrasting with “life-course-persistent variants” can be hypothesized as analogous to the “adolescence-limited” subtype of antisocial behaviours reported by Moffitt (1993). As noted above, the features of specific phobias, which appear to be particularly prevalent during the preschool period, could be conflated with normal developmental fears, or represent features of a normal developmental phase that will resolve with maturation. Longitudinal follow-up studies can track the developmental trajectories and differentiate whether “preschool-limited” and “life-course-persistent” subtypes exist.

Implications

Preliminary findings from out study, to be interpreted with caution, suggest that among preschool-aged children assessed with the PAPA, almost half yielded at least one diagnosis of a mental disorder. If problems are identified early, adjustments can be made before and once formal education begins, potentially preventing educational impacts from chronicity of mental disorders in later childhood and adulthood (Lyons-Ruth et al., 2017; Weisz et al., 2017). If mental health problems are left undetected, relationships with caregivers and peers may worsen over time and become more resistant to change (Bricker et al., 2004).

The relatively common occurrence of comorbidities (21% of children in our sample, 44% of those with a diagnosis according to the PAPA) suggests that children presenting with any mental disorder should be comprehensively assessed using a multi-methods assessment framework for a broad range of mental disorders. In addition, comorbidities may not be limited to “internalising” and “externalising” categories. When comorbid mental disorders are identified, coordinated child mental health services and treatments need to be accessible for a child and their family (Fisher, 2022). Comorbidity complicates treatment of children (Weisz et al., 2017); treatments that focus on single disorders may not be appropriate and may need to be replaced by treatments that consider multiple disorders (Barlow & Carl, 2012); the evidence for efficacy of such treatments is still limited and mostly among older children (Weisz et al., 2017).

Our findings also raise the possibility whether there exists a “preschool-limited” variant of psychopathology. Such variants can explain the high prevalence, analogous to the steep increase in anti-social behaviours in the adolescence window (Moffitt, 1993). Future studies with longitudinal design can explore this hypothesis; and if confirmed, examine the predictors of “preschool-limited” and “life-course-persistent” subtypes.

Our study suggests that clinicians and researchers should be aware of the relatively high prevalence of mental disorders and various comorbidities among these. Prior to the commencement of formal education, there is a window of opportunity to identify and manage disorders and lay the foundation for more optimal mental health and relationships.

Footnotes

Acknowledgments

The authors are extremely grateful to the participants for their ongoing participation in the study. We would also like to thank the MPEWS team of research coordinators and data collectors, without whom this work would not have been possible.

ORCID iDs

Karen Wynter

Wai Chen

Andrew Lewis

Josephine Power

Megan Galbally

Ethical Considerations

Consent to Participate

Each woman provided written consent to participate at each wave of data collection.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study is supported through the 2012 National Priority Founding Round of Beyondblue in a three-year research grant (ID 519240) and a 2015 National Health and Medical Research Council (NHMRC) project grant for 5 years (APP1106823). For Western Australian data, we would like to also acknowledge the support of the Spinnaker Foundation, Telethon Perth Children’s Foundation and WA Country Health Service in supporting this study. The funders had no involvement in the study design; the collection, analysis and interpretation of data; writing of the report; and the decision to submit the article for publication.

Declaration of Conflicting Interests

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

Author Biographies

Karen Wynter is a Senior Research Fellow at Centre for Women’s and Children’s Mental Health, Department of Psychiatry, Monash University, Melbourne, Australia and at Deakin Lifespan Institute, Faculty of Health, Deakin University, Melbourne, Australia.

Wai Chen is a Professor and the Psychiatry Discipline Lead at Curtin Medical School at Curtin University, Perth, Western Australia, Australia and a Professor of Youth Mental Health and Developmental Neuropsychiatry, Fiona Stanley Hospital, Perth, Western Australia, Australia.

Andrew Lewis is a Professor and the Pro Vice-Chancellor, Cooperative Education and the Institute of Health and Wellbeing, Federation University, Melbourne, Australia.

Josephine Power is the Deputy Program Director of Mental Health at Monash Health, Clayton, VIC, Australia.

Megan Galbally is a Professor, the Director of Centre for Women’s and Children’s Mental Health, Department of Psychiatry, Monash University, Melbourne, Australia and the Program Director of Mental Health at Monash Health, Clayton, VIC, Australia.

Appendix

References

Achenbach

T. M.

Edelbrock

C. S.

(1981). Behavioral problems and competencies reported by parents of normal and disturbed children aged four through sixteen. Monographs of the Society for Research in Child Development, 46(1), 1–82. https://doi.org/10.2307/1165983

Al-Jawadi

A. A.

Abdul-Rhman

(2007). Prevalence of childhood and early adolescence mental disorders among children attending primary health care centers in mosul, Iraq: A cross-sectional study. BMC Public Health, 7(1), 274. https://doi.org/10.1186/1471-2458-7-274

American Psychiatric Association . (2013). Diagnostic and statistical manual of mental disorders fifth edition (DSM-5). American Psychiatric Publishing Company.

Angold

Egger

H. L.

(2007). Preschool psychopathology: Lessons for the lifespan. Journal of Child Psychology and Psychiatry, 48(10), 961–966. https://doi.org/10.1111/j.1469-7610.2007.01832.x

Angold

Prendergast

Cox

Harrington

Simonoff

Rutter

(1995). The child and adolescent psychiatric assessment (CAPA). Psychological Medicine, 25(4), 739–753. https://doi.org/10.1017/s003329170003498x

Barican

J. L.

Yung

Schwartz

Zheng

Georgiades

Waddell

(2022). Prevalence of childhood mental disorders in high-income countries: A systematic review and meta-analysis to inform policymaking. Evidence-Based Mental Health, 25(1), 36–44. https://doi.org/10.1136/ebmental-2021-300277

Barlow

D. H.

Carl

J. R.

(2012). The Future of Clinical Psychology: Promises, Perspectives, and Predictions. In Barlow, D.H. (ed.), The Oxford Handbook of Clinical Psychology, 891-911. Oxford Library of Psychology (2010; online edn, Oxford Academic, 18 Sept. 2012), https://doi.org/10.1093/oxfordhb/9780195366884.013.0039, accessed 13 Feb. 2026.

Bricker

Davis

M. S.

Squires

(2004). Mental health screening in young children. Infants & Young Children, 17(2), 129–144. https://doi.org/10.1097/00001163-200404000-00005

Bufferd

S. J.

Dougherty

L. R.

Carlson

G. A.

Klein

D. N.

(2011). Parent-reported mental health in preschoolers: Findings using a diagnostic interview. Comprehensive Psychiatry, 52(4), 359–369. https://doi.org/10.1016/j.comppsych.2010.08.006

10.

Carter

A. S.

Wagmiller

R. J.

Gray

S. A.

McCarthy

K. J.

Horwitz

S. M.

Briggs-Gowan

M. J.

(2010). Prevalence of DSM-IV disorder in a representative, healthy birth cohort at school entry: Sociodemographic risks and social adaptation. Journal of the American Academy of Child & Adolescent Psychiatry, 49(7), 686–698. https://doi.org/10.1016/j.jaac.2010.03.018

11.

Center on the Developing Child . (2010). The foundations of lifelong health are built in early childhood. Available at. https://developingchild.harvard.edu/resources/the-foundations-of-lifelong-health-are-built-in-early-childhood/ accessed 25 November.

12.

Charach

Mohammadzadeh

Belanger

S. A.

Easson

Lipman

E. L.

McLennan

J. D.

Parkin

Szatmari

(2020). Identification of preschool children with mental health problems in primary care: Systematic review and meta-analysis. Journal of the Canadian Academy of Child and Adolescent Psychiatry, 29(2), 76–105.

13.

Danzig

A. P.

Bufferd

S. J.

Dougherty

L. R.

Carlson

G. A.

Olino

T. M.

Klein

D. N.

(2013). Longitudinal associations between preschool psychopathology and school-age peer functioning. Child Psychiatry and Human Development, 44(5), 621–632. https://doi.org/10.1007/s10578-012-0356-4

14.

Egger

H. L.

Angold

(2004). The preschool age psychiatric assessment (PAPA): A structured parent interview for diagnosing psychiatric disorders in preschool children. In: Handbook of infant, toddler, and preschool mental health assessment (pp. 223–243): Oxford University Press.

15.

Egger

H. L.

Angold

(2006). Common emotional and behavioral disorders in preschool children: Presentation, nosology, and epidemiology. Journal of Child Psychology and Psychiatry, 47(3-4), 313–337. https://doi.org/10.1111/j.1469-7610.2006.01618.x

16.

Egger

H. L.

Angold

Small

(2019). The preschool age psychiatric assessment: A structured parent interview for assessing psychiatric symptoms and disorders in preschool children. In: The Oxford handbook of infant, toddler, and preschool mental health assessment, 2nd ed (pp. 227–243): Oxford University Press.

17.

Egger

H. L.

Ascher

B. H.

Angold

(1999). Preschool age psychiatric assessment (PAPA). Duke University Medical Center.

18.

Egger

H. L.

Erkanli

Keeler

Potts

Walter

B. K.

Angold

(2006). Test-retest reliability of the preschool age psychiatric assessment (PAPA). Journal of the American Academy of Child & Adolescent Psychiatry, 45(5), 538–549. https://doi.org/10.1097/01.chi.0000205705.71194.b8

19.

First

M. B.

Spitzer

R. L.

Gibbon

(1997). Structured clinical interview for DSM‐IV clinical version (SCID‐I/CV). American Psychiatric Press.

20.

Fisher

H. L.

(2022). Editorial: The near ubiquity of comorbidity – What are the implications for children’s mental health research and practice? Journal of Child Psychology and Psychiatry, 63(5), 505–506. https://doi.org/10.1111/jcpp.13612

21.

Galbally

van

I. M.

Permezel

Saffery

Lappas

Ryan

van Rossum

Johnson

A. R.

Teti

Lewis

A. J.

(2017). Mercy pregnancy and emotional Well-being study (MPEWS): Understanding maternal mental health, fetal programming and child development. Study design and cohort profile. International Journal of Methods in Psychiatric Research, 26(4), Article e1558. https://doi.org/10.1002/mpr.1558

22.

Hattangadi

Kay

Parkin

P. C.

Birken

C. S.

Maguire

J. L.

Szatmari

van den Heuvel

Borkhoff

C. M.

Charach

TARGet Kids! Collaboration . (2024). Screening accuracy of the parent-report preschool strengths and difficulties questionnaire in primary care. Academic Pediatrics, 24(5), 800–809. https://doi.org/10.1016/j.acap.2023.10.007

23.

In-Albon

Equit

von Gontard

Schwarz

Müller

J. M.

Bolten

(2020). Das Strukturierte Interview für das Vorschulalter (SIVA: 0– 6). Reliabilität, Validität und Akzeptanz. [The Structured Interview for Preschool Ages (SIVA: 0–6): Reliability, validity, and acceptance.]. Kindheit und Entwicklung: Zeitschrift für Klinische Kinderpsychologie, 29(4), 209–220. https://doi.org/10.1026/0942-5403/a000319

24.

Jobs

Müller

J. M.

Skorozhenina

(2019). Homo- and heterotypic trajectories in a preschool to primary-school clinical sample: A prospective study related to maternal psychopathology. Frontiers in Psychiatry, 10. Article 153. https://doi.org/10.3389/fpsyt.2019.00153

25.

Lemeshow

Hosmer

Jr D. W.

Klar

(1988). Sample size requirements for studies estimating odds ratios or relative risks. Statistics in Medicine, 7(7), 759–764. https://doi.org/10.1002/sim.4780070705

26.

Lyons-Ruth

Manly

J. T.

Von Klitzing

Tamminen

Emde

Fitzgerald

Paul

Keren

Berg

Foley

Watanabe

(2017). The worldwide burden of infant mental and emotional disorder: Report of the task force of the world association for infant mental health. Infant Mental Health Journal, 38(6), 695–705. https://doi.org/10.1002/imhj.21674

27.

McGorry

Gunasiri

Mei

Rice

Gao

C. X.

(2025). The youth mental health crisis: Analysis and solutions. Frontiers in Psychiatry, 15, 1517533. https://doi.org/10.3389/fpsyt.2024.1517533

28.

Moffitt

T. E.

(1993). Adolescence-limited and life-course-persistent antisocial behavior: A developmental taxonomy. Psychology Review, 100(4), 674–701. https://doi.org/10.1037/0033-295X.100.4.674

29.

Müller

J. M.

Achtergarde

Furniss

(2011). The influence of maternal psychopathology on ratings of child psychiatric symptoms: An SEM analysis on cross-informant agreement. European Child & Adolescent Psychiatry, 20(5), 241–252. https://doi.org/10.1007/s00787-011-0168-2

30.

Müller

J. M.

Romer

Achtergarde

(2014). Correction of distortion in distressed mothers' ratings of their preschool-aged children's internalizing and externalizing scale score. Psychiatry Research, 215(1), 170–175. https://doi.org/10.1016/j.psychres.2013.10.035

31.

Pham

T. T. L.

Berecki-Gisolf

Clapperton

O'Brien

K. S.

Liu

Gibson

(2021). Definitions of culturally and linguistically diverse (CALD): A literature review of epidemiological research in Australia. International Journal of Environmental Research and Public Health, 18(2), 737. https://doi.org/10.3390/ijerph18020737

32.

Rapee

R. M.

Creswell

Kendall

P. C.

Pine

D. S.

Waters

A. M.

(2023). Anxiety disorders in children and adolescents: A summary and overview of the literature. Behaviour Research and Therapy, 168, Article 104376. https://doi.org/10.1016/j.brat.2023.104376

33.

Rogers

Obst

Teague

S. J.

Rossen

Spry

E. A.

Macdonald

J. A.

Sunderland

Olsson

C. A.

Youssef

Hutchinson

(2020). Association between maternal perinatal depression and anxiety and child and adolescent development: A meta-analysis. JAMA Pediatrics, 174(11), 1082–1092. https://doi.org/10.1001/jamapediatrics.2020.2910

34.

Vasileva

Graf

R. K.

Reinelt

Petermann

(2021). Research review: A meta-analysis of the international prevalence and comorbidity of mental disorders in children between 1 and 7 years. Journal of Child Psychology and Psychiatry, 62(4), 372–381. https://doi.org/10.1111/jcpp.13261

35.

Weisz

J. R.

Kuppens

M. Y.

Eckshtain

Ugueto

A. M.

Vaughn-Coaxum

Jensen-Doss

Hawley

K. M.

Krumholz Marchette

L. S.

Chu

B. C.

Weersing

V. R.

Fordwood

S. R.

(2017). What five decades of research tells us about the effects of youth psychological therapy: A multilevel meta-analysis and implications for science and practice. American Psychologist, 72(2), 79–117. https://doi.org/10.1037/a0040360

36.

Weitzman

Wegner

Section on Developmental and Behavioral Pediatrics Committee on Psychosocial Aspects of Child and Family Health Council on Early Childhood Society for Developmental and Behavioral Pediatrics American Academy of Pediatrics (2015). Promoting optimal development: Screening for behavioral and emotional problems. Pediatrics, 135(2), 384–395. https://doi.org/10.1542/peds.2014-3716

37.

Whalen

D. J.

Sylvester

C. M.

Luby

J. L.

(2017). Depression and anxiety in preschoolers: A review of the past 7 years. Child and Adolescent Psychiatric Clinics of North America, 26(3), 503–522. https://doi.org/10.1016/j.chc.2017.02.006

38.

Wichstrøm

Berg-Nielsen

T. S.

Angold

(2012). Prevalence of psychiatric disorders in preschoolers. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 53(6), 695–705. https://doi.org/10.1111/j.1469-7610.2011.02514.x

Comorbidities Among Mental Disorders in Preschool Children in the Mercy Pregnancy Emotional Wellbeing Study

Abstract

Background

Methods

Results

Conclusions

Plain Language Summary

Keywords

Introduction

Methods

Study Design

Recruitment

Measures

Statistical Methods

Ethics

Results

Discussion

Strengths and Limitations

Implications

Footnotes

Acknowledgments

ORCID iDs

Ethical Considerations

Consent to Participate

Funding

Declaration of Conflicting Interests

Author Biographies

Appendix

References