This sub-study of the WHO Determinants of Outcome of Severe Mental Disorders research project was aimed at characterizing the behavioral and expressive qualities of schizophrenia in two highly diverse cultures. Early research has indicated that the core elements involving affect, perceptual and cognitive dysfunction in schizophrenia are highly similar in form in most cultures of the world. Much of the cross-cultural literature emphasizes, however, strong differences in the ways in which schizophrenia is actually expressed and manifested in different settings. The basic methodology for psychiatric description and diagnosis in the WHO program was the Present State Examination. In five of the field centers a method for investigating the expressive quality and the social behavior of patients in their own communities through the eyes of significant others was applied. This method was then subjected to psychometric tests of cross-cultural applicability and found to be valid for comparing behavior across settings. The expressive patterns of the Indian and Nigerian patients were studied from two perspectives. Indian schizophrenics were described by family members as manifesting a more affective and "self-centered" orientation; the Nigerian patients presented with a highly suspicious, bizarre, anxious quality to the basic behavioral pattern. The main features of pathology were in general accord with the descriptions of indigenous psychiatrists. The special qualities of the psychosis in the two cultures were interpreted against the background of traditional psychopathological and anthropologic theories concerning the psychodynamics and the influence of differing social conflictual themes in the two cultures. Analysis of psychopathology in this manner was found to enhance understanding of underlying mechanisms and the role of cultural conflicts in its expression.