A systematic review of the persistence of childhood mental health problems into adulthood

Highlights

• Many adult mental disorders have their origins in childhood, but previous studies have been limited by retrospective recall.

• In this systematic review we identified 40 studies that assessed mental health prospectively in childhood and adulthood.

• Experiencing mental health problems before 14 years of age was associated with elevated risk for adult mental disorders.

• Prevention and early interventions should be targeted to primary school age children.

Abstract

Many adult mental disorders have their origins in childhood yet our knowledge about this largely comes from studies assessing adults utilising retrospective recall of age of onset. In this systematic review we evaluate the current state of knowledge of how childhood exposure to mental health problems is associated with adult mental disorders using data from prospective longitudinal studies. We identified 40 studies that assessed mental health in childhood or adolescence and reassessed adults for mental disorders. Although there was substantial heterogeneity across studies in terms of methodology and findings, there was a clear pattern that experiencing mental health problems prior to 14 years of age increases risk of adult mental disorder. Importantly, elevated symptoms rather than diagnosis in childhood were generally more strongly associated with adult disorder. These findings provide strong support for the argument that prevention needs to be targeted to children in the primary school years and early intervention efforts to those who are beginning to experience elevated symptoms rather than waiting until a diagnosable disorder is evident.

Introduction

In the 2010 Global Burden of Disease study, mental disorders were the leading cause of years lived with disability and the 4^th leading cause of disability-adjusted life years (DALYs) (Whiteford et al., 2013). Effective prevention and early intervention strategies for mental disorders therefore has the potential to significantly reduce the burden of disease globally as well as improve lives for individuals with mental disorders. In order to develop such strategies, it is crucial to properly understand the continuities and discontinuities of mental health disorders across development and to use this information to decide with whom we should intervene, and when this should happen.

Many mental disorders have their origins in childhood. For example, in a nationally representative sample of 9282 US adults, approximately 50 % of mental disorders began before the age of 14 years, with 75 % having an onset by 24 years (Kessler et al., 2005). Further support for this view comes from a review of the World Health Organisation’s World Mental Health Surveys, whereby the age of onset of mental disorders typically occurs in childhood and adolescence (Kessler et al., 2007). A key methodological limitation of these studies is that age of onset was estimated by retrospective recall of participants and as such, participants may be unable to recall symptoms with an earlier onset, for example in primary school years (Moffitt et al., 2010).

An accurate understanding of the extent to which early-onset mental disorders are associated with potentially lifelong mental disorders is critical for prevention and intervention efforts. Mental health problems in childhood are known to have adverse impacts across the lifespan including a more severe course of disorder and poorer prognosis (Copeland et al., 2015; Erskine et al., 2016). Crucially, the majority of mental health treatment services are targeted at adults (Jorm, 2014) and few children receive treatment for mental health problems (Mulraney et al., 2020). Having a greater understanding of the developmental trajectories of the major mental health disorders from childhood to adulthood is critical to inform the timing of treatment and intervention efforts. Such efforts have the potential to reduce the burden of mental health problems in childhood and also promote greater educational attainment, improved social functioning and prevent the development of new disorders in adulthood (Costello and Maughan, 2015).

An important question in understanding the course of mental health disorders is the degree of continuity between child and adult mental health problems and, whether the problems experienced in adulthood resemble those presenting in childhood (homotypic continuity) or whether they differ (heterotypic continuity). It is generally believed that homotypic (e.g. adult anxiety is preceded by anxiety in childhood) is more common than heterotypic continuity (Chiba et al., 1986). However, there is also evidence for heterotypic continuity for example, oppositional defiant disorder (ODD) in childhood is not only associated with disruptive behaviours in adults, but also with increased rates of mood disorders (Althoff et al., 2014). The identification of key childhood predictors and risk factors for adult mental disorder would provide important information about potential causes and preventative strategies for adult mental disorders.

This systematic review therefore evaluates the current state of knowledge about how mental health problems experienced prior to 14 years of age are associated with adult mental disorders (i.e., > 18 years). This review addresses the bias of retrospective recall of age of onset used in previous studies by reviewing studies employing prospective designs whereby children who had their mental health assessed prior to 14 years of age were followed into adulthood. To provide an in depth understanding of the current state of knowledge about homotypic versus heterotypic continuity, the review includes papers reporting on exposure to any mental health problem in childhood and a broad range of adult mental disorders.