The interplay between risk for schizophrenia and developmental factors in determining antisocial behavior are clarified. Those variables which distinguished high-risk criminal behavior from high-risk non-criminal behavior were irritability and shortened attention span in infancy, paternal absence during ages 15 to 17, lower WAIS Verbal IQ, impoverished neighborhood, family discord and negative attitude towards father. In a multiple regression analysis, paternal absence in adolescence, shortness of attention span, and low Verbal IQ each contributed a portion of the variance in antisocial behavior. A block of interaction terms (Stressor X Risk) did not contribute a significant portion of the variance in antisocial behavior, suggesting that those factors which predict antisocial behavior in the high-risk group are the same factors that predict antisocial behavior in the low-risk group. In addition, a significant portion of the variance in phenotypic outcome (criminal vs. schizophrenic) was accounted for by passivity in infancy (predictive of schizophrenia) and low Verbal IQ (more common in high-risk criminals). Shortened attention spans in infancy were found to precede both criminal behavior and schizophrenia that may indicate a genetic vulnerability to schizophrenia. (Author abstract modified)