Head size in relation to schizophrenia and schizotypy

Cranial breadth and length on DSM-III schizophrenic probands (n = 16) and their nonpsychotic siblings (n = 34) were measured using standard anthropometric calipers. Siblings were divided into those with and those without DSM-III schizotypal personality disorder based on Baron et al.'s Schedule for Schizotypal Personalities interview (1981). These siblings provide controls for prenatal and childhood nutritional status, which could affect head size, and for genetic contributors to head size. Contrary to previous reports (Andreasen et al. 1986; and Pearlson et al. 1989), in the present sample schizophrenic patients did not have smaller heads. The relationship between height and head size for schizophrenic subjects, schizotypal siblings, and nonschizotypal siblings was also examined. As in Andreasen et al. (1986), the regression slope of head size on height was lower in schizophrenic patients than in their siblings, but here this difference was not significant. The data do not support a conjectured relationship between small or dysmorphic head size and schizophrenia or schizotypy.