Adult Mental Disorders

Mental disorders are a diverse group of conditions that primarily impair cognition, emotion, and behavioral control; occur early in life; and have a high aggregate prevalence in all countries where epidemiology has been investigated (Demyttenaere and others 2004; Kessler, Berglund, and others 2005; WHO 1992). The combination of high prevalence, early onset, clinical course that is either chronic or remitting and relapsing, and impairment of critical brain functions makes mental disorders a major contributor to the global disease burden discussed in chapter 2 in this volume (Whiteford and others 2015). The greatest fraction of the burden results from years lived with disability (YLDs), particularly for ages 15–49 years—a critical life interval for completing education, starting a family, and increasing productivity at work (figure 4.1) (WHO 2014b). The global cost of mental health conditions is projected to be as high as US$6 trillion by 2030, of which 35 percent would be contributed by low- and middle-income countries (LMICs) (Bloom and others 2011).