Sex differences in the prevalence of mental disorders have long been established. 2 , 3 , 4 , 5 Irrespective of the absolute rates of disorders, the sex ratio for specific classes of mental disorders is quite consistent in community surveys of both youth and adults. Table 1 presents sex differences in lifetime prevalence, onset, and severity or clinical manifestations of psychiatric disorders. As described in Table 1, there is a female preponderance of mood disorders (male:female ratio [M:F] 0.8), anxiety disorders (M:F 0.7) and eating disorders (M:F 0.3), and males have greater rates of alcohol (M:F 2.2) and substance use (M:F 1.7) disorders, and behavior disorders (ie, attention deficit hyperactivity disorder [ADHD], oppositional defiant disorder [ODD] and conduct disorder [CD]). 6 , 7 Not all disorders exhibit these disparities in prevalence between males and females. The sex ratio is approximately equal for bipolar disorder and for schizophrenia. 8 Studies of childhood conditions show that the rates of neurodevelopmental disorders (eg, autism spectrum disorder (ASD, M:F 4.0), ADHD (M:F 1.5) and CD) are substantially greater in males than females. Rates
