Family study of acute and transient psychotic disorders: comparison with schizophrenia

Background: Acute non-organic psychoses, as often described in European and Indian literature, and categorized as 'Acute and transient psychotic disor ders' in ICD-10, lack a clear nosological distinction from schizophrenia. M ethods: A family study of psychiatric disorders in first-degree relatives ( FDRs) of 40 ICD-10-diagnosed probands of acute and transient psychotic diso rders (ATP) was carried out using a semi-structured interview schedule. The results were compared with those of 40 schizophrenic probands. Results: FD Rs of ATP probands had a higher prevalence of ATP than those of schizophren ic probands. FDRs of schizophrenic probands had significantly higher preval ence of schizophrenia than those of ATP probands. ATP subtypes with schizop hrenic symptomatology (ICD-10 codes F 23.1 and F 23.2) had more family hist ory of schizophrenia than the rest of the ATP subtypes. Conclusion: ATP as a group has a differential pattern of risk of illness compared to schizophr enia. Further, the subtypes subsumed under ICD-10 ATP may be genetically he terogeneous, those with schizophrenia-like symptomatology being possibly mo re akin to schizophrenia itself or forming an interface between ATP and Sch izophrenia.