Recurrence risk for the relatives of delusional depressed patients.

The recurrence risks for major depression among the relatives of patients with delusional depression have been calculated using a computer program. The risk tables have been based on the data from the 454 first-degree relatives of 77 probands with delusional depression, the 503 first-degree relatives of 76 non-delusional probands and the 980 first-degree relatives of 153 controls. The results showed that: the familial aggregation of the delusional depression seem to follow the multifactorial pattern of inheritance (segregation analysis), the heritability of the delusional depression was found to be 62, the recurrence risk varies from 0.5% to 36.2% for the various relatives and tables for recurrence risks are provided.