This article uses a version of the vulnerability-stress model to examine psychosocial factors related to the onset, course, and treatment of schizophrenia. High-risk studies, most of which study offspring of a schizophrenic parent, suggest that signs of vulnerability to the disorder may emerge in early to middle childhood in neuromotor integration, attentional and information-processing abilities, and deviant social behavior. It is still not clear that these markers are specific to the subsequent development of schizophrenia. The evidence for stressful family relationships as potentiators of the disorder in vulnerable off-spring is also reviewed. Although few studies are available that bear directly on this issue, the preliminary evidence suggests that further investigation is warranted. Stressors, particularly those arising from within the family, are also examined as they relate to the course of schizophrenia. The data on expressed emotion (EE) have been replicated more often than not, although the origins of high EE attitudes are not precisely understood. These attitudes do not arise as reactions to the form or severity of a relative's disorder, but they may relate to the length of time between initial onset of the disorder and first hospitalization. Family-based intervention programs, overlaid on regular antipsychotic drug treatment, appear to reduce the risk for relapse in the short-term. At least one of the mechanisms of action of these programs is to reduce the negative affective climate in the family.