Temperament and psychopathology amongst siblings of probands with depressive and anxiety disorders.

Thirteen (42%) of 31 siblings of 29 probands with depression (n = 21) or anxiety disorders (n = 8) attending a clinic met DSM-IIIR criteria for psychiatric disorder, a rate nearly three times greater than reported from community studies. The diagnoses were heterogeneous. Compared with probands, sibling cases had half the level of comorbidity and significantly lower levels of psychosocial impairment. Comparisons of temperamental characteristics showed that higher levels of emotionality, but no other aspect of temperament, was associated with an increased likelihood of a sibling being a case. Higher emotionally in all cases (sibs and probands) was associated with greater comorbidity in general and the diagnoses of dysthymia and separation anxiety in particular.