Abstract
We describe the key findings from the Child and Adolescent Component of the National Survey of Mental Health and Well-Being and their implications for those providing mental health services to young people in Australia. Previously in this journal we have described the background and the methodology employed in the survey [1].
While there have been several surveys of the mental health of young people in individual states of Australia [2–4], this is the first epidemiological study which describes the prevalence of child and adolescent mental health problems at a national level. Previous studies have included work by Connell et al. [3] in Queensland who surveyed 986 children aged 10–11 years using the same methodology as that employed by Rutter et al. in the Isle of Wight Study [5]. Connell et al. [3] reported an overall prevalence of psychiatric disorder of 14%%, with children in rural areas having a somewhat lower prevalence of disorders than children living in urban areas. Sawyer et al. [2] surveyed 528 children aged 10–11 years or 14–15 years living in metropolitan Adelaide using the Child Behaviour Checklist (CBCL) [6] and reported that 21%% of children in the younger group and 15%% in the older group scored above the recommended cut-off score on the checklist. In Western Australia, Zubrick et al. [4] surveyed 2737 children aged 4–16 years living in 1462 households using the CBCL and the Teacher Report Form (TRF) [7]. The authors reported that 18%% of the children had a mental health problem, defined as a score above the recommended cut-off on either the CBCL or the TRF. The most frequently reported problems were on the checklist scales which identified ‘delinquency problems’, ‘thought problems’ and ‘attention problems’ [4].
The aims of the Child and Adolescent Component of the National Survey of Mental Health and Well-Being were to identify: (i) the number of children in Australia with mental health problems (ii) the nature of these problems (iii) the degree of disability associated with mental health problems, and (iv) the services being used by children with mental health problems (for brevity, in this report the term ‘children’ will be used to refer to both children and adolescents). The survey also examined the prevalence among adolescents of behaviours harmful to health and their association with mental health problems.
Mental health problems were identified by parents and adolescents using standard behaviour checklists [8]. The prevalence of childhood mental disorders was investigated using a structured diagnostic interview completed by parents [8]. The National Collaborating Group responsible for conducting the survey chose three mental disorders (Depressive Disorder, Conduct Disorder and Attention-Deficit/Hyperactivity Disorder) for inclusion because; (i) they are known from previous studies to be prevalent in the community (ii) they have great significance for child and adolescent health in Australia and (iii) they could be examined within the funding and time constraints of the study. It was not possible to include Anxiety Disorders as the assessment of these disorders with the interview schedule employed in the survey is complex and their inclusion would have required another group of disorders to be dropped. The exclusion of Anxiety Disorders is unfortunate, because other surveys have shown these disorders to be relatively common among children and adolescents. It should be noted that if a wider range of disorders had been investigated, a higher prevalence of mental disorders would have been identified in the survey.
Method
Participants
The participants were 4509 children aged 4–17 years. This sample size allowed for acceptable precision in prevalence estimates at a national level with confidence intervals of ± 1%%, assuming a prevalence of childhood mental disorders of approximately 15%%. The lower age limit for the survey was determined by the capacity of the survey instruments to provide valid and reliable ratings of the mental health problems of younger children. The upper age limit of 17 years was determined by the lower age limit of the survey of adults.
The survey utilised a multi-stage probability methodology designed to identify participants. ‘Clusters’ of 10 fully responding households with children in the required age-range were sampled from each of 450 Census Collector's Districts across Australia. The number of districts sampled within each state or territory was in proportion to the size of the target populations within each region, and were also distributed proportionately across metropolitan and nonmetropolitan areas [8].
The participation rate was 86%% (this is calculated as the proportion of households that were contacted, identified to contain a child aged 4–17 years, and agreed to participate). The response rate was 70%% (this also takes into account the number of noncontacted households estimated to contain a child between the ages of 4 and 17 years). The major factor that affected the response rate was the replacement of households before the interviewers completed the specified number of callbacks. To assess for sample bias we compared the demographic characteristics of children, parents and families who participated in the study with the characteristics of the population from which they were selected (based on the 1996 Australian Census). These comparisons suggested that children aged 16–17 years had been slightly undersampled and those aged 4–5 years slightly over-sampled. Estimates of the prevalence of mental health problems were adjusted for these discrepancies by appropriate weights. In all other areas, the demographic characteristics of the survey sample were highly comparable with the Australian Bureau of Statistics Census figures.
Measures
Mental health problems
Mental health problems were assessed by means of the CBCL [6] completed by the children's primary caregivers (predominantly mothers). The CBCL assesses childhood emotional and behavioural problems in a range of areas and ratings are summarised as scores on a Total Behaviour Problem Scale which is comprised of all the behaviour items on the checklist, an Externalising Scale which rates antisocial or undercontrolled behaviour, and an Internalising Scale which rates inhibited or overcontrolled behaviour. Scores on syndrome scales can be employed to assess more specific aspects of the children's emotional and behavioural problems. The CBCL has been widely used in studies of both clinic and community populations and extensive information is available about its reliability and validity [6].
For the purpose of presenting survey results, children and adolescents were considered to have a mental health problem if their score on the relevant CBCL scale was in the clinical range (i.e. it was above the recommended cut-off score) [6]. This approach identifies children and adolescents whose scores are in the range typically reported for those of the same age and gender who are attending mental health clinics. The raw cut-off score that defines the lower limit of the clinical range on each behaviour problem scale varies for children of different age and gender. As a result, it is necessary to be cautious when comparing the prevalence of problems across the age and gender groups. To address this issue, comparisons between age and gender groups were made by using average behaviour problem scores rather than the percentages who scored above the recommended cut-off scores. The results of these comparisons are available in the main report from the survey [8].
In addition to identifying children who scored in the clinical range on the CBCL, we also identified children who scored in a ‘subthreshold range’. These were children whose T-score was in the range 54–59 on the Total Behaviour Problem Scale of the CBCL (the recommended cut-off for the clinical range on the Total Behaviour Problem Scale is T-score = 60). Inclusion of this group in the analysis of results made it possible to determine whether children who scored in the subthreshold range also experienced problems in areas such as their quality of life or health-risk behaviours, or whether problems in these areas were restricted to children who scored in the clinical range.
Mental disorders
The parent-version of the Diagnostic Interview Schedule for Children Version IV (DISC-IV) was employed to detect the three mental disorders examined in the survey among the 6–17-year-olds (the DISC-IV is designed to identify disorders in children older than five years) [9], [10]. The DISC-IV is based on the Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition [9] and the diagnoses in the present study were based on the most current algorithms recommended to identify children with a mental disorder in the last year. With the exception of the impairment criteria and the exclusion of a diagnosis due to the presence of another comorbid disorder, these algorithms employ the same criteria for psychiatric diagnoses as the DSM-IV. The interview has been shown to have acceptable testretest reliability for the disorders included in the survey [10].
Health-related quality of life
The 50 item parent version of the Child Health Questionnaire (CHQ) [11] was completed by the primary caregiver of children aged 6–17 years. The questionnaire assesses the quality of life of children in several domains and also rates the impact of children's problems on their parents and families. As recommended in the CHQ manual, prior to the analysis of results the raw score on each scale was transformed to a 0–100 scale with higher scores indicating a better quality of life. The use of a common metric across all the scales makes it possible to compare the functioning of children in the different domains assessed by the measure. The questionnaire has been shown to be reliable with high levels of internal consistency on all the scales. Factor analytic techniques and comparison with results obtained using established measures have been used to assess the validity of the scales [11].
For the purpose of reporting results in the present study, the names of some CHQ scales were altered to better reflect the items that comprise each scale. The summary names which were changed (with the published names in parentheses) were Pain and Discomfort (Bodily Pain), Physical Activities (Physical Functioning), Emotional Problems (Mental Health), and Behavioural Problems (Behaviour).
Service utilisation
The survey asked about a wide range of services used by children and adolescents during the previous 6 months. For the purpose of the present report, the parent response to the question ‘During the past 6 months, has (child) received any help for emotional or behavioural problems?’ was used in the analysis of results.
Adolescent health-risk behaviour
Information about health-risk behaviour was obtained from adolescents using relevant items from the Youth Risk Behaviour Questionnaire (YRBQ). The YRBQ was developed by the Centers for Disease Control and Prevention in the United States to identify healthrisk behaviour in high school students [12]. It asks adolescents to identify health-risk behaviour in a range of areas including tobacco use, alcohol and other drug use, dietary behaviour, and suicide ideation and behaviour.
Results
Prevalence of mental health problems
The prevalence of mental health problems for 4–17-year-olds is shown in Table 1. Fourteen percent of children and adolescents in the survey scored in the clinical range on the Total Problems scale on the CBCL, while 13%% scored in the clinical range on the Externalising and Internalising scales. The percentage of children with scores in the clinical range on the individual syndrome scales are also shown in Table 1. Children were most frequently identified as having problems on the Somatic Complaints, Delinquent Behaviour, and Attention Problems Scales.
Prevalence (%%) of mental health problems in 4–17–year–old children
Table 2 shows the 1 year prevalence of the three mental disorders assessed in the survey among 6–17-year-olds. The most common disorder was ADHD, which had a prevalence of 11%%. This was comprised of 6%% of children with the Inattentive Subtype, 3%% with the Combined Subtype and 2%% with the Hyperactive-Impulsive Subtype. The prevalence of Depressive Disorder and Conduct Disorder was 3.0%%. Males had a higher prevalence of ADHD (χ2 1df = 71.7, P < 0.001) and Conduct Disorder (χ2 1df = 26.2, P < 0.0001) than did females. Among adolescents the prevalence of Depressive Disorder was not significantly higher in females than males (χ2 1df = 0.5, P = 0.5). Among children the prevalence was higher in males (χ2 1df = 7.7, P < 0.01).
One-year prevalence (%%) of mental disorders in 6–17–year–old children
Demographic characteristics
The demographic characteristics of children in the clinical, subthreshold and non-clinical groups on the CBCL are shown in Table 3. Across the three groups, those in the clinical group were more likely to live in low-income families with single or step-parents, parents who had left school at an earlier age, and parents who were unemployed. In all these areas, children in the subthreshold group occupied an intermediate position between the clinical and non-clinical groups. In multivariable analyses controlling for the effect of the four variables in Table 3, the adjusted Odds Ratio for family structure (step/blended & sole parent vs. original parents) was 2.0 (95%% CI = 1.6–2.6) and that for leaving school under the age of 17 years was 1.3 (95%% CI = 1.0–1.6). The Odds Ratios for the other two variables were not significant (P < 0.05) in these analyses.
Demographic characteristics of parents and families for 4–17–year–old children
Health-related quality of life
The average scores on the CHQ scales reported for children in the clinical, subthreshold and non-clinical groups are shown in Table 4. The physical and mental health of children scoring in the clinical range was consistently rated as worse than that of children in the other two groups. It is not surprising that parents of children in the clinical group reported that their children had a lower self-esteem or more emotional and behavioural problems than those in the non-clinical group. However, differences were not restricted to these areas. For example, children in the clinical group also had significantly lower scores on the General Health Perceptions and the Pain and Discomfort Scales than children in the other groups.
Mean (SD) parent-reported scores on the Child Health Questionnaire in 6–17–year–old children
The perceived impact of children's problems was most evident on the scales assessing impact on Family Activities, Peer and School Activities due to Emotional and Behavioural Problems, and the two scales assessing the impact of problems on parents. On all of these scales the scores describing children in the clinical group were significantly lower (denoting higher perceived impact) than those of children in the other groups. In several areas the effect sizes were in the range ≥ 0.8 SD, defined as a large effect [13]. The results suggest that in a broad range of areas, parents of children with mental health problems perceive their children's problems to have a significant impact on children, parents and families. A similar pattern was evident when analyses focused on the relationship between the three mental disorders and children's scores on the CHQ [8].
In all the domains assessed by the CHQ there was a consistent pattern for children in the non-clinical group to have the highest CHQ scores (denoting lowest perceived impact and best quality of life), those in the clinical group to have the lowest scores, and those in the subthreshold range to be intermediate between the other two groups (Table 4). This suggests that there was a ‘dose–response’ relationship between the level of children's mental health problems, their level of health-related quality of life (HRQL) and the perceived impact of children's problems on children, parents and families.
Service use
Overall, 25%% of those in the clinical group, 12%% of those in the subthreshold range and 3%% of those in the non-clinical range had attended at least one of the services listed in Table 5 during the 6 months prior to the survey to get help for emotional and behavioural problems. Two other findings are evident in this table. First, the services most frequently attended by children with mental health problems were family doctors, counselling in schools and paediatricians. With the exception of psychologists and social workers in private practice, no mental health service was attended by more than 5%% of children in the clinical group. Second, only a very small proportion of those in the non-clinical group were reported to be attending professional services to get help for emotional and behavioural problems. This pattern, which is consistent with results of other analyses examining this issue [7], suggests that the great majority of children attending services have substantial mental health problems.
Percentage of children aged 4–17–years–old attending services
Adolescent health-risk behaviour
Odds ratios describing the risk for health-risk behaviours among adolescents in the clinical and subthreshold groups on the CBCL are shown in Table 6. Children in both the clinical and subthreshold groups were at increased risk for suicidal ideation and behaviour compared to those in the non-clinical group. To address the issue of operational confounding (which may arise when similar items are included in questionnaires assessing dependent and independent variables), these analyses were repeated after removing the items on the CBCL which assess suicidal ideation and behaviour. When this was done, the results varied little from those reported in Table 6. Adolescents with mental health problems more frequently smoked cigarettes and used marijuana but they did not appear to be at increased risk for alcohol use.
Odds ratios (95%% CI) for health-risk behaviours reported by adolescents
Discussion
Fourteen percent of children were identified as having mental health problems in this survey. This is very similar to the median prevalence of 12%% reported by Verhulst and Koot [14] in their review of 49 international studies conducted between 1965 and 1993. However, the prevalence is lower than the 18%% reported in the Western Australian Child Health Survey [4]. The reason for this difference is that parent-reported and adolescentreported mental health problems are described separately in the present survey, whereas results reported in the Western Australian survey were based on the combined reports of parents and teachers. When the prevalence of parent-reported and adolescent-reported problems in each survey were compared, the results were very similar.
Fifteen percent of children and adolescents met the criteria for one of the three mental disorders assessed in the survey. Males were more likely to have one of these disorders than were females (19%% vs. 10%%). This is not surprising, given that two of the three disorders studied (Conduct Disorder and Attention-Deficit/Hyperactivity Disorder) are known to be more common among males. Children aged 6–12 years were more likely to have a disorder than were adolescents aged 13–17 years (17%% vs. 11%%). This finding was primarily due to the large number of children who met symptom criteria for Attention-Deficit/Hyperactivity Disorder. While the prevalence of ADHD is higher than that reported in studies using the criteria described in earlier versions of the DSM, it is consistent with the rates reported in more recent studies using DSM-IV criteria [15] Limitations of the present study include the inclusion of only three mental disorders, the lack of teacher reports and the inability to use impairment criteria when assessing mental disorders. However, the similarity of the results to those in other comparable studies suggests that overall, these limitations have not had a major impact on the assessment of the prevalence of mental health problems in young people in Australia.
Child and adolescent mental health problems were not equally distributed among all demographic groups. Rather, there was a higher proportion of mental health problems among children living in step/blended or sole parent families, in lower income households, with parents who were not in paid employment, and with parents who had left school at an earlier age. The identification of high-risk groups is important because it makes it possible to ensure that treatment and preventative programs are accurately targeted and resources efficiently employed. Services should be sensitive, for example, to the particular needs of single-parent or low-income families. There is also a continuing need for research which can provide a better understanding of the mechanisms which give rise to these relationships.
Only a minority of children and adolescents with mental health problems had received professional help. Among those children who ‘met the criteria for a mental disorder’ and ‘scored in the top 10%% of scores on the Child Behaviour Checklist’ and whose ‘parent reported that their child needed help’, only 50%% had attended any professional service during the past six months [8]. Furthermore, only 17%% of this group had attended a mental health service. These findings highlight the extent to which children with mental disorders fail to receive professional help. Among those not receiving help, parents reported that practical issues such as the cost of attending services, not knowing where to get help, and long waiting lists were the major obstacles to getting help. Concern about the attitude of others was identified as a barrier by only a small minority of these parents [8].
The high prevalence of problems and the limited number of trained clinicians available to provide help make it unlikely that specialised programs in secondary and tertiary treatment settings (e.g. child and adolescent mental health services or departments of psychiatry) will ever be able to provide face-to-face care for all those with problems. There is therefore a need to identify alternative approaches to reduce the prevalence of child and adolescent mental health problems. Parents identified counselling in schools as one of the services most frequently used by children with mental health problems. This finding is consistent with the results of other recent international surveys, and it emphasises the key role that school-based services play in providing help for children with mental health problems [16]. In the present survey it is unclear which professional group was providing this counselling. If teachers are providing the service it is important that they receive adequate training. Alternatively, schools could be provided with additional funding to appoint specialist counsellors skilled in the identification and management of children with mental health problems. It is important to ensure that teachers or counsellors responsible for helping children with mental health problems are closely linked to specialised mental health services.
The school environment is an important part of the social life of young people and many mental health problems emerge for the first time during the years that young people attend school. Potential access to young people through schools offers an important opportunity to utilise universal, selective and indicated interventions to help large numbers of those with mental health problems and those who are at risk for developing problems in the future. However, such interventions will only be successful if close cooperation is achieved between staff working in health and education services.
Family doctors and paediatricians were the other services commonly used by children and adolescents with mental health problems. Most children and adolescents attending mental health services have a very high level of problems [8], however, only a very small proportion of all children and adolescents with problems receive help from specialised mental health services. This finding poses a major challenge for scarce mental health services. Mental health services should be encouraged to experiment with alternative models of service delivery that combine direct care, consultation to primary health care or school-based services, and universal, selective or indicated interventions. There is a great need to identify the optimal mix of promotion, prevention, consultation and treatment interventions that can provide costeffective help for young people and their families in Australia [17].
The strong association between mental health problems and suicidal ideation and behaviour is consistent with results from several previous studies [18], [19]. Suicide is a major cause of death among adolescents in Australia, particularly among males. Adolescents experiencing suicidal ideation and those with a previous history of suicidal behaviour are at a markedly greater risk of future death by suicide than their peers. The high rates of suicidal ideation and behaviour among adolescents with mental health problems suggest that they are an important target group for programs designed to reduce suicide.
Traditionally, health services have tended to focus their attention on a particular problem. For example, psychiatric services focus on mental health, drug and alcohol services on drug and alcohol abuse, and paediatric services on physical health. Furthermore, as Andrews et al. [20] have pointed out, clinical practice guidelines often concentrate on the management of a single mental disorder. This narrow approach, however, does not reflect the complexity of health problems experienced by adolescents, as young people with a high level of problems in one area often experience difficulties in other areas of their lives. Individual professions and services must pay more attention to the high levels of comorbid problems in young people, and they need to develop strong collaborative relationships with each other if they are to provide adolescents with effective help for their problems. Further research is needed to provide a better understanding of the mechanisms that give rise to the broadly based problems experienced by adolescents.
This report summarises key findings from the Child and Adolescent Component of the National Survey of Mental Health and Well-Being. In future publications we will report the results of further analyses, including factors which influence service utilisation, the quality of life of children with mental disorders, and the extent to which psychotropic medications are being used to treat childhood mental disorders. The high prevalence of mental disorders presents a major challenge to communities, service providers and governments in Australia. We hope that the publication of results from this survey will be used by these groups to better coordinate their efforts to reduce the public health problem posed by mental disorders experienced by children and adolescents.
Footnotes
Acknowledgements
The Child and Adolescent Component of the National Survey of Mental Health and Well-Being was funded by the Commonwealth Department of Health and Aged Care. The authors would like to express their gratitude to Mr D Casey for his ongoing advice and encouragement during the course of the study. We would also like to thank Mr E Brinkley and the Australian Bureau of Statistics for advice about the study methodology and Ms M Drake, Professor P Hazell, Professor S Henderson, Professor R McKelvey, Mr S Silburn, Dr V Storm, Associate Professor H Winefield and Professor H Whiteford for their valuable contributions to the study.