Abstract
Introduction
One in seven Australian young people aged 4–17 years have a mental disorder; however, only half receive mental health care (Sawyer et al., 2018). Mental health problems in childhood and adolescence are associated with an increased likelihood of adult mental disorders (Mulraney et al., 2021). Understanding the types of mental health services accessed during childhood and adolescence is paramount to improving the provision of mental health care and addressing potential inequities in service access. Most Australian research has relied on cross-sectional data (Segal et al., 2018), while the few longitudinal studies have focussed on specific health service types (Hiscock et al., 2020). Drawing on longitudinal multi-agency administrative data for a representative population cohort in New South Wales (NSW), Australia, this study examined the proportion of young people who used mental health services during key developmental periods of childhood and adolescence.
Methods
Participants were 90,162 young people followed from birth (2002–2005) to age ~18 years (2021) in the NSW Child Development Study Wave 3 Linkage cohort (Green et al., 2024), with data available from the Australian Institute of Health and Welfare (AIHW) Medicare Benefits Schedule (MBS, 2002–2021) and/or Pharmaceutical Benefits Scheme (PBS, 2001–2021), NSW Mental Health Ambulatory (MH-AMB, 2001–2020) and/or NSW and ACT Emergency Department (EDDC, 2005–2021) and/or Admitted Patient Data Collections (APDC, 2001–2020). Record linkages were conducted by the NSW Centre for Health Record Linkage (CHeReL) and the AIHW Data Integration Service Centre. Ethical approval was provided by the NSW Population and Health Services and ACT Health Human Research Ethics Committees (HREC/18/CIPHS/49) and the AIHW Human Research Ethics Committee (EO2020/4/1026) under the ‘waiver of consent’ provision of the National Statement of Ethical Conduct in Human Research.
Mental health service use was identified from the MBS data set (using item numbers indicating mental health services delivered by general practitioners, psychologists, psychiatrists and other health professionals), the PBS data set (using World Health Organization Anatomical Therapeutic Chemical Classification codes for antipsychotics [N05A], anxiolytics [N05B], hypnotics and sedatives [N05C], antidepressants [N06A] and/or psychostimulants, agents used for attention deficit hyperactivity disorder and nootropics [N06B]), and the MH-AMB, EDDC and APDC data sets (using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification codes for mental and behavioural disorders [F00–F99], suicidal ideation [R45.81, R45.851] and/or intentional self-harm [X60–X84, T14.91, Y87.0] represented in primary and/or secondary recorded diagnoses).
Dates of health service access were used to categorise mental health service use into non-mutually exclusive developmental periods spanning: any age between 0 and ~18 years, ages ~0–5 years (birth to 31 December 2009; early childhood), ages ~6–11 years (1 January 2010 to 31 December 2015; middle childhood) and ages ~12–18 years (1 January 2016 to 31 December 2021; adolescence). Mental health service use during these developmental periods was examined in relation to sex assigned at birth. Descriptive analyses and figure generation were performed in RStudio version 2024.04.2 using R version 4.4.1.
Results
In total, 42,656 (47.3%) young people had a record of health service use for mental health reasons during childhood and/or adolescence (Table 1). Mental health service use was more prevalent between ages 12 and 18 years (40.6%), relative to ages 0–5 and 6–11 years (5.8% and 20.0%, respectively). MBS-subsidised health services were the most heavily accessed service type regardless of age. Among young people at any age, and when they were aged 6 years and older, PBS-subsidised medications were the second most commonly used service type, followed by ambulatory mental health services. Emergency department presentations were more common than hospital admissions between ages 12 and 18 years, while the rates of emergency department presentations and hospital admissions were similar during ages 6–11 years. The pattern of mental health service use varied for ages 0–5 years, with ambulatory mental health services being the second most commonly used service, followed by hospital admissions and PBS-subsidised medications (with similar rates), and the emergency department was the least commonly used service type. Overall, 23.1% of young people accessed two or more health service types, which was most prominent between ages 12 and 18 years. More males used mental health services during ages 0–5 and 6–11 years compared with females, whereas more females accessed mental health services between ages 12 and 18 years; this pattern was observed for all types of health services. Half of the young people with a record of mental health service contact accessed mental health services when they were aged between 12 and 18 years only (53.3%, Figure 1).
Mental health service use during key developmental periods of childhood and adolescence (n = 90,162).
MBS: Medicare Benefits Schedule, PBS: Pharmaceutical Benefits Scheme.
A young person’s mental health service use could have been recorded in more than one developmental period and mental health service type.
Combines data for ages 0–18 years.
Proportions were calculated using the number of young people with any mental health service use during the corresponding developmental period as the denominator.
Proportion of young people who used mental health services during single or multiple developmental periods of childhood and adolescence among 42,656 young people with at least one record of mental health service contact by age ~18 years.
Discussion
In a representative population sample of ~90,000 Australian young people followed from birth to age ~18 years, almost half (47.3%) had a record of using subsidised primary (i.e. MBS and PBS), ambulatory and/or hospital mental health services during childhood and/or adolescence. There is limited comparable data in Australia as local studies have often examined health service types separately or mental health service use during a specific period (e.g. previous 12 months) (Hiscock et al., 2020; Segal et al., 2018).
A striking finding was that half of the young people with a record of mental health service use in this sample received mental health care during adolescence only. However, 35.6% of the young people who used mental health services during adolescence also accessed these services during middle childhood, consistent with previous estimates that one-third of all mental disorders begin by age 14 years (Solmi et al., 2022). The accumulation of stressors during different stages of adolescence – a dynamic period of physical, cognitive and psychosocial development – can contribute to the risk of mental health problems and mental health service use (Suppiej et al., 2025). For example, early to middle adolescence is characterised by puberty, identity exploration and evolving peer relationships, while late adolescence involves changing social roles, identity consolidation and new intimate relationships. Prevention and early intervention strategies which acknowledge the unique challenges faced by young people at different stages of development can assist to reduce mental health service needs during adolescence.
PBS-subsidised medications were accessed less than ambulatory mental health services during early childhood compared with the other developmental periods. This pattern corresponds with the relatively lower rates of mood and neurodevelopmental disorders prior to school entry (Solmi et al., 2022), and our previous work showing that the most common psychotropic medications used during childhood and adolescence in this cohort were antidepressants and psychostimulants (Watkeys et al., 2025). In line with existing literature (Afroz et al., 2025), we observed that males accessed mental health services earlier than females. Given that approximately half of the young people with mental health service contact in this study used two or more health service types (48.8%), collectively examining mental health service use across settings is essential for informing service delivery. Notably, not all mental health service use was captured by the data sets included in this study. Strengths of this study were the large sample size, low selection bias and length of follow-up.
In summary, nearly half of all young people in this longitudinal cohort study received mental health care during childhood and/or adolescence. Mental health services were less utilised during early and middle childhood, relative to adolescence. This observational study provides important insights to inform the provision of timely supports for this population.
Footnotes
Acknowledgements
This research used population data owned by the NSW Ministry of Health; ACT Health; NSW Registry of Births, Deaths and Marriages; NSW Department of Education and Australian Institute of Health and Welfare. This research used data from the Australian Early Development Census (AEDC). The AEDC is funded by the Australian Government Department of Education. The findings and views reported are those of the authors and should not be attributed to these Departments and Agencies, or the NSW, ACT and Australian Governments. Record linkages were conducted by the NSW Centre for Health Record Linkage (CHeReL) and the Australian Institute of Health and Welfare Data Integration Service Centre.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This research was conducted with financial support from the National Health and Medical Research Council (NHMRC) Project Grant (APP1148055); Australian Research Council (ARC) Discovery Project (DP230101990); Department of Health, Disability and Ageing Medical Research Future Fund Million Minds Mental Health Grant (APP2006436) and Australian Government Department of Health, Disability and Ageing’s National Suicide Prevention Research Fund, managed by Suicide Prevention Australia (Postdoctoral Fellowship awarded to OW). The funders had no role in the design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the manuscript; or decision to submit the manuscript for publication.
Ethical approval
Ethical approval was provided by the NSW Population and Health Services and ACT Health Human Research Ethics Committees (HREC/18/CIPHS/49) and the Australian Institute of Health and Welfare Human Research Ethics Committee (EO2020/4/1026) under the ‘waiver of consent’ provision of the National Statement of Ethical Conduct in Human Research.
Data availability statement
Data used in this project have been provided by government custodians for research purposes of the NSW Child Development Study and are unable to be shared with third parties or deposited into data repositories. Collaborative research activities may be possible depending on scope and resources; alternatively, researchers wishing to access these data sets can apply directly to the relevant data custodians.