Diagnosis provision by young people’s mental health services: a comparison with epidemiological data

medRxiv [Preprint]. 2026 Jun 5:2026.05.28.26354156. doi: 10.64898/2026.05.28.26354156.

ABSTRACT

BACKGROUND: Little is known about the provision of diagnoses to young people with mental health disorders. We investigated diagnosis provision by NHS mental health services, focusing on 17-year-olds in South London between 2009-2024, and compared with estimated disorder prevalence.

METHODS: To examine diagnosis provision in the population, we extracted diagnosis data from records of the NHS mental healthcare provider serving South London, using the Maudsley Biomedical Research Centre Clinical Record Interactive Search application; we then compared these data with the corresponding population size, obtained from the Office for National Statistics. To assess diagnosis provision in those with mental health disorders, we compared diagnosis data with the number of young people estimated to have met criteria for a disorder, derived from epidemiological interview data collected in the Environmental Risk (E-Risk) Longitudinal Twin Study and weighted according to characteristics of 17-year-old South Londoners. To assess diagnosis provision in those with mental health disorders within health services, we compared diagnosis data with the number estimated to have met criteria for a disorder and used any health service for their mental health, again derived from weighted E-Risk Study data.

FINDINGS: Of 17-year-olds from South London in 2009-2024, 4.0% (n=8,958/223,404) had a diagnosis in mental health records during the previous year. This diagnosis provision covered <1 in 16 of those estimated to have had a mental health disorder, and <1 in 4 of those estimated to have also used health services. Diagnosis provision was lower in girls than boys and in young people with Black/Asian/Mixed/Other ethnicity than those with White ethnicity, in those estimated to have had a mental health disorder and used health services.

INTERPRETATION: These findings demonstrate gaps and biases in mental health diagnosis provision for young people, including within health services, and reveal the imperative need to strengthen young people’s mental healthcare.

FUNDING: National Institute for Health Research, Medical Research Council, National Institute of Child Health and Development, Jacobs Foundation, National Society for Prevention of Cruelty to Children, Economic and Social Research Council, Prudence Trust, Wellcome Trust.

RESEARCH IN CONTEXT: Evidence before this study: Epidemiological research has found that less than half of young people with a mental health disorder report seeing a health professional for their symptoms and only a quarter to a third have seen a mental health specialist, and these findings are fairly consistent across high-income countries where this research has been conducted. For young people who see health professionals, there are likely to be barriers to the recognition and treatment of mental health disorders. We focused on the recognition of mental health disorders in young people, which is operationalised in clinical practice as provision of diagnoses. To identify studies examining mental health diagnosis provision in young people accessing health services, we searched MEDLINE with the terms “diagnos*” AND (“mental” OR “psychiatr*” OR [various terms for individual disorders]) AND (“young” OR “youth*” OR “child*” OR “adolescen*” OR “paedatric*” OR “pedatric*” OR “juvenile”) AND (“clinical” OR “healthcare” OR “health care” OR “service*”). This search was supplemented by reviewing reference lists and forward citations of relevant articles. We identified several studies that found diagnosis provision varied by sociodemographic characteristics and has increased over the past two decades in young people across multiple countries for several disorders, including depression, anxiety disorders, eating disorders, autism, and attention-deficit/hyperactivity disorder (ADHD). Only a small number of studies investigated diagnosis provision within young people who met criteria for a disorder. In the Avon Longitudinal Study of Parents and Children in the UK, of 18-year-olds who met criteria for depression, only 7.0% had a diagnosis of depression documented in their primary care records. In the Child and Adolescent Twin Study in Sweden, of 9-year-olds who met criteria for ADHD, only 18.5% of boys and 12.1% of girls had a diagnosis of ADHD noted in their health records. Within an Irish child and adolescent mental health service, of 12-15-year-olds who met criteria for depressive disorder, only 28.4% received a depressive disorder diagnosis after their usual clinical assessment. These studies suggest large gaps in diagnosis provision, including within health services, and highlight possible bias by sociodemographic characteristics. A better understanding of this topic is needed to enable more effective service planning, commissioning, and policymaking.Added value of this study: This study investigated mental health diagnosis provision in 17-year-olds from South London. We examined diagnosis provision for several mental health disorders in NHS mental healthcare records. We compared these data with population and epidemiological data to calculate diagnosis provision rates in the general population, in those estimated to have met criteria for a disorder, and in those estimated to have also seen a health professional. We found that diagnosis provision substantially increased during our study period of 2009-2024, demonstrating an increase in the number of young people whose mental health needs were recognised in specialist services. However, we estimated that diagnoses were only provided to a small proportion of young people with a mental health disorder, including those within health services. Estimated diagnosis gaps were largest for those with generalised anxiety disorder and multiple disorders. We also found evidence of biases in diagnosis provision, based on gender, neighbourhood deprivation, and ethnicity.Implications of all the available evidence: Barriers to mental healthcare access for young people should be reduced by policymakers and commissioners, including through investment in adequately staffed services with skilled clinicians, enabling more young people with mental health disorders to receive cost-effective evidence-based healthcare that has long-term benefits. Greater awareness among clinicians of the under-diagnosis and bias in diagnosis of young people’s mental health disorders, alongside strategies to address these problems, could improve young people’s mental healthcare. Innovative scalable interventions that can reach many more young people need to be developed, evaluated, and implemented by researchers. Prevention strategies are also required, including addressing risk factors for young people’s mental health disorders, and intervening early for those with symptoms before disorders develop, to reduce the future burden of mental health disorders in young people.

PMID:42282172 | PMC:PMC13252444 | DOI:10.64898/2026.05.28.26354156