Roughly half of all Americans will have a psychiatric disorder in their lifetime with most beginning in childhood or adolescence, according to an article in the June issue of the Archives of General Psychiatry.

Ronald C. Kessler, PhD, of Harvard Medical School, and colleagues based their conclusions in an analysis of data from the National Comorbidity Survey Replication (NCS-R). Lifetime prevalence for the different classes of disorders were anxiety disorder, 28.8 percent; mood disorders, 20.8 percent; impulse-control disorders, 24.8 percent; substance use disorders, 14.6 percent and lifetime prevalence for any disorder, 46.4 percent.

Median age of onset was much earlier for anxiety and impulse-control disorders (11 years for both) than for substance use (20 years) and mood disorders (30 years), the researchers found. Half of all lifetime cases started by age 14 years and three fourths by age 24 years.

".the NCS-R results clearly document that mental disorders are highly prevalent, that lifetime prevalence is, if anything, underestimated, that age-of-onset distribution for most of the disorders considered herein are concentrated in a relatively narrow age range during the first two decades of life, and that later onset disorders occur in large part as temporally secondary comorbid conditions," the authors conclude.

"Given the enormous personal and societal burdens of mental disorders, these observations should lead us to direct a greater part of our thinking about public health interventions to the child and adolescent years and, with appropriately balanced considerations of potential risks and benefits, to focus on early interventions aimed at preventing the progression of primary disorders and the onset of comorbid disorders."