Assessed the severity of indices of burden among relatives of 75 schizophrenics and 20 major affective disorder cases (aged 15-75 yrs), to identify the factors associated with burden, to assess the relationship between caregiver burden and patients' perception of social support, and to compare these with equivalent data for cancer patients' relatives. Caregivers were assessed, using a burden questionnaire and Goldberg's General Health Questionnaire (GHQ-12). Patients were assessed for perception of social support from the extended family. Results found that clinical severity and burden indices were similar for the psychiatric illness groups. However, relatives of patients with psychotic symptoms, uncooperative behaviour, marital instability and unemployment had significantly higher GHQ scores; while patients from such families perceived a wider social support network. Disruption of family routines, GHQ scores and (inversely) size of family network patient expected support from, predicted global rating of burden. Although clinical severity and disruption of family routines for cancer patients were higher; relatives of psychiatric patients had higher GHQ scores, more family disharmony and greater social stigma.