A group of patients, initially 67 individuals, with chronic schizophrenia were studied on repeated occasions during 1 year and followed up after 3 years. The patients were given depot neuroleptics, either fluphenazine decanoate or pipotiazine palmitate, at intervals of 1 month. The symptom scores from three rating scales were subjected to factor analysis. Four factors were found to explain the variance satisfactorily: one comprising psychopathological symptoms specific for schizophrenia, one relating to contact disturbances, one psychomotor activity and one representing neurotic symptoms. Analysis of these factors revealed certain differences between the treatment groups over time and demonstrated the effect of combination of psychotherapy and neuroleptic drugs in a subgroup of patients. This type of analysis of treatment results might contribute to improving our knowledge of rehabilitation of schizophrenic patients and help us to draw up giudelines for selection of suitable measures.