Incidence of psychiatric disorder in offspring at high and low risk for depression.

First onsets (incidence) of suicide attempts and DSM-III psychiatric disorders, including major depression, any anxiety disorder, conduct disorder, or substance abuse were determined in a 2-year longitudinal study of 174 offspring at high and low risk for major depression. All of the suicide attempts, the first onsets of major depression, and anxiety disorders were in offspring of depressed parents. Compared with asymptomatic offspring, offspring with subclinical manifestations of major depression, conduct disorder, and substance abuse at the initial interview were significantly more likely to become incident cases of the same disorder over the next 2 years. Either conduct disorder or substance abuse at initial interview were highly predictive of first onset of each other, but not of any other disorders 2 years later. Family risk factors (such as poor marital adjustment, parent-child discord, low cohesion, and affectionless control) at initial interview were associated with increased incidence of substance abuse, or conduct disorder, but not major depression or anxiety disorder. Combining both retrospective and prospective data, the overall suicide attempt rate was 7.8% in the offspring of depressed parents as compared with 1.4% in the offspring of nondepressed parents. By age 20, over 50% of the offspring of depressed patients reported a major depression.