Twenty-five intervention studies were meta-analytically examined regarding the effect of including relatives in schizophrenia treatment. The studies investigated family intervention programs to educate relatives and help them cope better with the patient's illness. The patient's relapse rate, measured by either a significant worsening of symptoms or rehospitalization in the first years after hospitalization, served as the main study criterion. The main result of the meta-analysis was that the relapse rate can be reduced by 20 percent if relatives of schizophrenia patients are included in the treatment. If family interventions continued for longer than 3 months, the effect was particularly marked. Furthermore, different types of comprehensive family interventions have similar results. The bifocal approach, which offers psychosocial support to relatives and schizophrenia patients in addition to medical treatment, was clearly superior to the medication-only standard treatment. The effects of family interventions and comprehensive patient interventions were comparable, but the combination did not yield significantly better results than did a treatment approach, which focused on either the patient or the family. This meta-analysis indicates that psychoeducational interventions are essential to schizophrenia treatment.