Age at onset as an index of genetic heterogeneity in major psychiatric and substance use disorders
Background Robust clinical indices of etiologic heterogeneity for psychiatric disorders are rare. We investigate whether age at onset (AAO) reflects genetic heterogeneity, utilizing Genetic Risk Ratios (GRR) derived from Family Genetic Risk Scores (FGRS). Methods We examined, in individuals born in Sweden 1940-2003, whether AAO for five primary disorders - drug use disorder (DUD), alcohol use diso