Young people aged 10–24 years represent 27% of the world’s population. Important health issues and risk factors for disease occurrence in later life emerge in those years, and their contribution to the global incurrence of disease is relevant. Using data from WHO’s 2004 Global Burden of Disease study, Gore et al. (2011) calculated cause-specific disability-adjusted life-years (DALYs) for young people aged 10–24 years on the basis of available estimates for incidence, prevalence, severity, and mortality. They estimated DALYs attributable to specific global health risk factors using the comparative risk assessment method, and they divided DALYs into years of life lost because of premature mortality (YLLs) and years lost because of disability (YLDs). The total number of incident DALYs in those aged 10–24 years was about 236 million, representing 15·5% of total DALYs for all age groups. The eight main causes of DALYs in this age group were all psychiatric and behavioural in nature: unipolar depressive disorders (8.2%); road traffic accidents (5.4%); schizophrenia (4.1%); bipolar disorder (3.8%); violence (3.5%); alcohol use (3.0%); HIV/AIDS (3.0%); and self-inflicted injuries (2.8%). In high-income countries neuropsychiatric disorders were the main cause of burden in those aged 15–24 years (50 DALYs per 1,000 males and 52 DALYs per 1,000 females).
This data show that, although this age group has generally been perceived as healthy, young people suffer from a relevant neuropsychiatric morbidity as well (de Girolamo et al., 2012; . Many large-scale prospective epidemiological studies, carried out in Europe, confirm this situation with regard to the psychological ill-health of adolescents and young people (Odelhinkel et al., 2011, Wasserman et al., 2010, Ford et al., 2003); moreover, cross-sectional studies have shown that the exposure to risk-factors in childhood and adolescence increases the probability of developing mental health disorders in adulthood (Scott et al, 2011; Bruffaerts et al., 2010; Kessler et al., 2007, 2010). 2
Moreover, temporal trends in incidence rates of mental disorders among adolescents and young people are a highly debated area. There is evidence of increased rates of substance abuse (Degenhardt et al., 2013) and suicide (Patel, 2012) over the last decades; on the contrary, more controversial is the case of depression, since some authors have stated that rates of depression did not increase in the last 30 years (Costello et el., 2006). Rates of schizophrenia have not decreased, and there has been an increase of substance-induced psychosis over time (Kirkbirde et al., 2009). These data again highlight the need for improved mental health care in these ‘transition to adult years’.