Mental illnesses are among the leading causes of disability in the world. Research shows that most adult mental illnesses begin in childhood and adolescence. It is important to understand how common mental illnesses are in children and adolescents, and how they themselves may increase the risk for self-harm and other adverse outcomes.
Because published evidence reporting on the number of new cases of mental illnesses that occur yearly is out of date, it is unclear if the number of young people affected by these conditions has increased in recent years. We plan to examine the number of new cases of mental illnesses that have occurred in the past 16 years among children and adolescents in the UK.
Evidence also shows that individuals who self-harm often develop mental illnesses before they first self-harm. The association between mental illnesses, suicide and self-harm and has not been studied among younger individuals in the UK, nor has it focused on those registered with a general practitioner. For this reason, we will study patterns of general practice consultations, mental illness diagnoses, and prescription of drugs for treating mental illnesses, which occur before individuals harm themselves. In addition, there are no treatment guidelines for anxiety disorder among children and adolescents - one of the most common mental illnesses among young people. We will therefore examine how young persons are treated by their GP after they first receive a diagnosis of an anxiety disorder with the purpose of informing treatment guidelines.
Objectives and Method:
Study 1: Estimate incidence of common mental illnesses in a cohort of individuals aged 1-19, and examining temporal trends in annual incidence (Cohort study).
Study 2: Individuals aged 10-19 years with an index fatal or non-fatal self-harm episode will be ascertained to build a nested case-control study to estimate relative risk of self-harm and suicide among individuals diagnosed with specific mental illnesses compared to those without, and relative risks in relation to patterns of GP consultation, psychotropic drug prescription, and area-level socioeconomic status. (Nested case-control study)
Study 3: Examine how frequently individuals aged 6-19 years are referred to mental health services, psychotropic medication prescribing patterns, and how often patients consult with their GP 12 months prior to and following an initial diagnosis with an anxiety disorder (Cohort study)
Analysis:
Study 1: Annual incidence will be estimated from the number of incident cases during each calendar year (2003 to 2018) in relation to the total number of individuals at risk. Rates will be stratified by gender, age and practice-level deprivation (IMD quintiles).
Study 2: Conditional logistic regression models will be used to estimate relative risk for non-fatal and fatal self-harm via calculation of exposure odds ratios.
Study 3: We will report proportions of individuals that are hospitalised, referred to mental health services and prescribed specific types of psychotropic medication, after an initial diagnosis with an anxiety disorder. Analyses will be stratified by practice-level deprivation (IMD quintiles) and according to comorbid mental illness diagnoses.
Objective: To estimate annual incidence of mental illnesses in individuals between the ages of 1 and 19 (Study 1).
To examine how risk for fatal and non-fatal self-harm varies according to specific mental illness diagnosis, by total number of mental illness diagnoses given, by type and number of psychotropic drugs prescribed, by area-level socioeconomic status, and by frequency of GP consultations (Study 2). To examine treatment and referral patterns of individuals between the ages of 6 and 19 years who have been diagnosed with an anxiety disorder (Study 3).
Aims:
Study 1
i) To estimate the annual incidence of common mental illnesses among individuals between the ages of 1 and 19. The specific conditions examined will be as follows: depression, anxiety disorder, autism spectrum disorder, attention-deficit hyperactivity disorder, conduct disorder, eating disorders, and learning disabilities. The annual incidence for each mental illness will be stratified by age group (1-5, 5-9, 10-12, 13-16, & 17-19), gender and index of multiple deprivation quintile
Study 2:
i) To estimate relative risk of non-fatal and fatal self-harm associated with the following exposures: mental illness diagnosis (depression, anxiety disorder, autism spectrum disorder, attention-deficit hyperactivity disorder, conduct disorder, eating disorders and learning disabilities), as well as index of multiple deprivation quintile and the number of GP consultations and psychotropic drugs prescribed in the 12 months preceding the first self-harm or suicide event. Based on research conducted in other countries, we expect elevated risk for self-harm (including death from suicide) among individuals diagnosed with a mental illness. In particular, we expect the risk for self-harm to be highest in individuals with eating disorders and conduct disorder, relative to other mental illnesses. Based on previous research that we have conducted using CPRD data(1) on self-harm risk among adults, we also expect number of prescribed psychotropic medications, diagnoses, consultations to positively correlate with self-harm, whilst we expect a positive association between rising levels of deprivation and self-harm risk. Finally, we will estimate the 5 most prevalent comorbid combinations of mental illnesses (e.g., ADHD and anxiety disorder) to examine if some combinations of mental illnesses are more strongly associated with self-harm than others.
Study 3:
i) To estimate the frequency of referrals to mental health services and prescription of psychotropic medication among 6 to 19 year olds 36 months before after being diagnosed with an anxiety disorder or having symptoms of anxiety. Frequency counts will be stratified by age, gender, and practice level IMD quintile, and also whether individuals have a record indicating a categorical diagnosis of an anxiety disorder or symptoms of anxiety and other comorbid mental illnesses (ADHD, autism, conduct disorder, depression, eating disorders and learning disabilities)
Rationale:
By addressing these aims we will describe the incidence of mental illnesses of children and adolescents in the UK in the past 16 years. Because studies that report on mental illness incidence are dated, the current understanding of child and adolescent mental illness epidemiology is limited. This is problematic because there is increasing proximal evidence that mental illnesses at a very young age have become considerably more prevalent in recent years. By presenting data for multiple illnesses at the same time and from the same data source, we will provide researchers, clinicians, policymakers and patient groups and other relevant stakeholders with a contemporary and comparative overview that currently is not available (Study 1). Recent evidence shows that some adolescent populations have rising incidence of self-harm. To identify individuals at increased risk we will identify precursors and markers for fatal and non-fatal self-harm among children and adolescents who are registered in primary care. Very little is known about precursors for suicide in younger populations. (Study 2). Finally, we will examine how GPs treat young individuals with anxiety disorders, as currently no primary care clinical treatment guidelines exist, and gaining this new knowledge may usefully inform the development of new evidence-based guidelines. (Study 3).
Roger Webb - Chief Investigator - University of Manchester
Lukasz Cybulski - Corresponding Applicant - University of Manchester
Carolyn Chew-Graham - Collaborator - Keele University
Darren Ashcroft - Collaborator - University of Manchester
Matthew Carr - Collaborator - University of Manchester
Navneet Kapur - Collaborator - University of Manchester
Shruti Garg - Collaborator - University of Manchester
HES Accident and Emergency;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation