Purpose of review The aim of this article is to review recent epidemiological research on age-of-onset of mental disorders, focusing on the WHO World Mental Health surveys. Recent findings Median and inter-quartile range (IQR; 25th–75th percentiles) of age-of-onset is much earlier for phobias (7–14, IQR 4–20) and impulse–control disorders (7–15; IQR 4–35) than other anxiety disorders (25–53, IQR 15–75), mood disorders (25–45, IQR 17–65), and substance disorders (18–29, IQR 16–43). Although less data exist for nonaffective psychosis, available evidence suggests that median age-of-onset is in the range late teens through early 20s. Roughly half of all lifetime mental disorders in most studies start by the mid-teens and three quarters by the mid-20s. Later onsets are mostly secondary conditions. Severe disorders are typically preceded by less severe disorders that are seldom brought to clinical attention. Summary First onset of mental disorders usually occur in childhood or adolescence, although treatment typically does not occur until a number of years later. Although interventions with early incipient disorders might help reduce severity-persistence of primary disorders and prevent secondary disorders, additional research is needed on appropriate treatments for early incipient cases and on long-term evaluation of the effects of early intervention on secondary prevention.

Research from JAMA Psychiatry — Long-Chain ω-3 Fatty Acids for Indicated Prevention of Psychotic Disorders — A Randomized, Placebo-Controlled Trial

To provide an update of the recent studies on the age of onset of the major mental illnesses, with a special focus on the prospects for prevention and early intervention. The studies reviewed here confirm previous reports on the age of onset of the major mental disorders. While the behaviour disorders, and certain anxiety disorders, emerge during childhood, most of the high prevalence disorders (anxiety, mood and substance use) emerge during adolescence and early adulthood, as do the psychotic disorders. Early age of onset has been shown to be associated with a longer duration of untreated illness and poorer clinical and functional outcomes. Although the onset of most mental disorders usually occurs during the first three decades of life, effective treatment is typically not initiated until a number of years later. Although there is increasing evidence to suggest that intervention during the early stages of a disorder may help reduce the severity and/or the persistence of the initial or primary disorder and prevent secondary disorders, additional research is needed into appropriate treatment for early stage cases as well as the long-term effects of early intervention, and to appropriate service design for those in the early stages of a mental illness. This will mean not only the strengthening and re-engineering of existing systems but also, crucially, the construction of new streams of care for young people in transition to adulthood.

Research from JAMA Psychiatry — Heterogeneity of Psychosis Risk Within Individuals at Clinical High Risk — A Meta-analytical Stratification