Age of Onset in Familial Schizophrenia

Abstract

The age of onset of schizophrenia chatacteristically peaks in early adulthood, although spanning at least four decades of life among unrelated individuals, and on average, it peaks a few years earlier in males than females.^1,2 It also has been previously shown that the age of onset, rather than the time of onset, is highly correlated among affected sibling pairs, thus suggesting a genetic determination of the age of on set. There recently have been reports of a curious lack of gender differences in the age of onset when only schizophrenic individuals with a positive family history of schizophrenia (ie, multiplex families) are examined.^4-6 However, L. S. Penrose, in a large cohort of familial mental illness, previously observed that the age of onset for males was lower than for females (mean difference, 3.7 years), with a wider scatter in male ages at first admission than in female and a