Sibling resemblance for psychiatric disorders in offspring at high and low risk for depression

This study examined sibling resemblance for major depressive disorder, anxiety disorder, and conduct disorder, in offspring at high and low risk for depression by virtue of parental diagnosis. The sample, which ranged in age from 6 to 23 years, included 164 sibling pairs at high risk, and 68 sibling pairs at low risk. Each cohort was assessed at two waves separated by a 2-year period. Sibling resemblance in the high risk cohort was substantially greater than resemblance in the low risk cohort for anxiety disorder (and comorbid conditions including anxiety disorder), but not depression. Discussion focused on the possibility that anxiety disorder may reflect the most pronounced familial influences common to siblings at high risk for depression.