Mental health of young people in Australia

3 Prevalence of mental health problems

Page last updated: October 2000

The prevalence of mental health problems is based on scores obtained from the scales of the Child Behaviour Checklist (CBCL) completed by parents. The CBCL scales identify mental health problems in three general areas and eight specific areas (table 3.1) (Achenbach, 1991a). This approach provides a broad assessment of child and adolescent mental health problems in Australia.

The identification of child and adolescent mental health problems inevitably depends on the assessment procedure and the source of information (e.g., parents, children and adolescents, or teachers). It is impossible to determine a 'true' prevalence that is independent of these procedures (Crijnen, Achenbach, & Verhulst, 1997). In each area, 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 threshold score) (Achenbach, 1991a). This approach identifies children and adolescents whose score is in the range typically reported for those of the same age and gender who are attending mental health clinics. The prevalence of these problems was examined separately for males and females in two age groups (4–12 years and 13–17 years) to determine whether the problems are experienced by all age and gender groups or are limited to only some groups.

The advantage of this approach is that it is possible to compare results in the present survey with results from previous Australian and international surveys that used the same methodology (Verhulst & Koot, 1995). This approach also identifies the number of males and females in each age group who have a high level of problems on each behaviour scale. The disadvantage of the approach is that the threshold score that defines the clinical range on each behaviour problem scale is not the same for each age and gender group. As a result, it is necessary to be cautious when comparing the prevalence of mental health problems reported for different age and gender groups (appendix A).

Prevalence of mental health problems
Relationships between mental health problems and demographic characteristics
Summary
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Table 3.1 Mental health problems assessed by the Child Behaviour Checklist

Table 3.1 is presented as a list in this HTML version for accessibility reasons. It is presented as a table in the PDF version.
  • General areas:

    1. Internalising Problems Scale: inhibited or over-controlled behaviour (e.g., anxiety or depression).
    2. Externalising Problems Scale: antisocial or under-controlled behaviour (e.g., delinquency or aggression).
    3. Total Problems Scale: all mental health problems reported by parents or adolescents.

  • Specific areas:

    1. Somatic Complaints Scale: chronic physical complaints without known cause or medically verified basis.
    2. Delinquent Behaviour Scale: breaking rules and norms set by parents and communities (e.g., lying, swearing, stealing or truancy).
    3. Attention Problems Scale: difficulty concentrating and sitting still, and impaired school performance.
    4. Aggressive Behaviour Scale: bullying, teasing, temper tantrums and fighting.
    5. Social Problems Scale: impaired peer relationships.
    6. Withdrawn Scale: shyness and social isolation.
    7. Anxious/Depressed Scale: feelings of loneliness, sadness, being unloved, worthlessness, anxiety and general fears.
    8. Thought Problems Scale: strange behaviour or ideas, obsessions.

Prevalence of mental health problems

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 (table 3.2). The percentage of those in different age and gender groups with scores in the clinical range of the Internalising and Externalising scales are shown in table 3.2.

The specific problems most frequently identified by parents were Somatic Complaints and Delinquent Behaviour, with 7% of children and adolescents scoring in the clinical range on each scale (table 3.3). The next most frequently identified problems were Attention Problems (6%) and Aggressive Behaviour (5%).

As the threshold scores used to establish the clinical range vary with age and gender, the prevalence of mental health problems across these different groups cannot be compared directly. To address this issue, the comparisons in this section were repeated using the average behaviour problem scores in each group rather than the percentage scoring above the recommended threshold score (appendix A). These comparisons, rather than the prevalence of problems shown in table 3.2 and table 3.3, should be used to compare the typical level of problems experienced by children and adolescents in different age and gender groups. It is apparent from the results in appendix A that even though a particular age and gender group may have a higher proportion of children or adolescents scoring in the clinical range than another group, it cannot be assumed that on average all children or adolescents in that group have more problems than those in the other group.
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Table 3.2 Prevalence (%) of total problems, externalising problems and internalising problems

Total problems %Total problems Population estimateaExternalising problems %Externalising problems Population estimateInternalising problems %Internalising problems Population estimate
All Children
14.1
521,886
12.9
475,748
12.8
473,989
Males 4–12 year olds
15.0
181,749
13.6
164,992
15.0
182,032
Males 13–17 year olds
13.4
90,678
11.7
78,965
13.6
92,244
Females 4–12 year olds
14.4
166,817
12.2
141,121
11.3
130,309
Females 13–17 year olds
12.8
82,221
14.1
90,726
10.7
68,788

a estimated number of children and adolescents with a mental health problem in Australia

Table 3.3 Prevalence (%) of mental health problems in specific areas

CBCL ScaleAll children4-12 years
Males
4-12 years
Females
13-17 years
Males
13-17 years
Females
Somatic Complaints
7.3
7.2
5.6
10.6
6.8
Delinquent Behaviour
7.1
7.4
7.8
6.4
5.9
Attention Problems
6.1
7.4
6.2
4.8
4.6
Aggressive Behaviour
5.2
5.9
5.2
5.0
4.0
Social Problems
4.6
6.5
3.9
3.8
3.0
Withdrawn
4.3
5.4
2.9
4.8
4.2
Anxious/Depressed
3.5
4.1
2.9
3.6
3.6
Thought Problems
3.1
3.2
2.7
3.4
3.1
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Relationships between mental health problems and demographic characteristics

The relationships between the prevalence of mental health problems and the demographic characteristics of children and adolescents are shown in table 3.4, table 3.5, table 3.6 and table 3.7. Children and adolescents living in sole-parent, step/blended or low-income families were more likely to have mental health problems. In addition, both males and females living with parents not in paid employment had a higher prevalence of externalising problems than those in families where parents were employed. Finally, there was some evidence that females living in metropolitan regions had a higher prevalence of externalising problems than those in non-metropolitan regions.

Table 3.4 Prevalence (%) of mental health problems by family type

CBCL scaleOriginal parents
Males
Original parents
Females
Step/blended parents
Males
Step/blended parents
Females
Sole parent
Males
Sole parent
Females
Total Problems
11.3
10.7
25.0
19.7
22.2
26.7
Internalising Problems
12.1
9.0
23.0
13.5
20.4
19.5
Externalising Problems
9.5
9.8
23.9
19.9
21.4
24.7

Table 3.5 Prevalence (%) of mental health problems by weekly household income

CBCL scaleLess than $580$581 to $1030Greater than $1030
Males - Total Problems
21.1
14.8
8.9
Males - Internalising Problems
17.5
15.6
11.8
Males - Externalising Problems
20.4
13.0
7.2
Females - Total Problems
22.1
13.8
9.1
Females - Internalising Problems
16.4
10.5
8.8
Females - Externalising Problems
20.4
11.7
9.6
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Table 3.6 Prevalence (%) of mental health problems by parental labour force status

Table 3.6 is separated into 2 smaller tables in this HTML version for accessibility reasons. It is presented as one table in the PDF version.

Two-parent households

Labour force statusCBCL scale
Total problems
CBCL scale
Internalising
CBCL scale
Externalising
Males - Both employed
10.7
12.7
7.9
Males - One employed, one not in paid employment
12.7
13.2
11.3
Males - Both not in paid employment
18.1
16.2
18.5
Females - Both employed
9.4
9.0
9.4
Females - One employed, one not in paid employment
12.5
9.1
9.4
Females - Both not in paid employment
16.0
9.0
21.9

Single-parent households

Labour force statusCBCL scale
Total problems
CBCL scale
Internalising
CBCL scale
Externalising
Males - Employed
20.3
22.1
16.7
Males - Not in paid employment
24.2
19.7
25.9
Females - Employed
19.7
17.8
19.6
Females - Not in paid employment
31.0
20.8
27.6
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Table 3.7 Prevalence (%) of mental health problems by region

CBCL ScaleMetropolitan
Males
Metropolitan
Females
Non–metropolitan
Males
Non–metropolitan
Females
Total Problems
14.7
15.8
14.0
10.6
Internalising Problems
14.8
11.3
14.0
10.8
Externalising Problems
12.6
14.3
13.4
10.6

Summary

Children and adolescents of both genders had a high prevalence of mental health problems. This shows that a high prevalence of mental health problems is not limited to a particular age or gender group.

Overall, the prevalence of problems identified in this survey is very similar to those reported in previous international surveys (Verhulst & Koot, 1995). This suggests that the prevalence rates determined by the survey are a true reflection of the extent of problems in the community and not an artifact of the survey methodology. The prevalence of mental health problems, however, is lower than that reported in the Western Australian Child Health Survey (Zubrick et al., 1995). The reason for this difference is that parent-reported and adolescent-reported 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 was compared, the results were very similar.

Several demographic characteristics were found to have a strong association with mental health problems. Generally, there was a higher proportion of mental health problems among those living in step/blended or sole parent families, those living in lower income households and those living with parents who were not in paid employment. It is important to note, however, that this survey cannot determine whether the demographic characteristics of children and adolescents cause their mental health problems. For example, there are several possible explanations for the relationship between low income and mental health problems. Although children might experience problems as a result of deficient family resources, it is also possible that their problems make it difficult for parents to retain well-paid employment. Alternatively, it could be that another independent factor, such as parental ill health, is responsible for both low family income and the children's mental health problems. To obtain a better understanding of these issues it is necessary to follow the development of children and adolescents over time.

The results of the present survey draw attention to demographic groups where the prevalence of mental health problems is high. It is important that further studies be conducted to understand why the prevalence of problems is high in these groups and what can be done to provide help and to prevent the future onset of problems.
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