Prevalence of psychotic and non-psychotic disorders in relatives of patients with a first episode psychosis.

Abstract Background Family members of individuals with schizophrenia suffer from elevated rates of schizophrenia-spectrum disorders (SSD) and other forms of psychopathology. However, few studies have examined familial psychopathology in probands with a first episode of psychosis (FEP). We systematically evaluated family history in patients experiencing an affective or non-affective FEP. Methods The Family Interview for Genetic Studies was used to obtain diagnostic information on all first- and second-degree relatives of probands admitted to a specialized FEP program. Probands were 94 previously untreated patients suffering from a first-episode of affective or schizophrenia spectrum psychosis, aged 14 to 30. The interview ascertained diagnoses of psychotic disorders, affective disorders, substance-use disorders (SUD), and schizophrenia-related personality disorders. Results One in five probands (19.1%) had a history of psychosis among their first-degree relatives, while 34.0% had any relative with psychosis. Fewer probands had a family history of SSD (7.4% with a first-degree history and 18.1% with a history among any relatives). Over half (53.2%) of probands had a first-degree relative with Major Depressive Disorder, and 38.3% had a first-degree relative with a SUD. Overall, 69.9% of probands had a first-degree relative with a mental disorder. The proportion of probands with a family history of any of these diagnoses did not vary by proband diagnosis (affective or SS Psychosis), though probands with co-morbid SUD were more likely to have a family history of substance abuse. Conclusions Diverse psychopathology is commonly present in families of FEP patients and may imply a generalized vulnerability to psychiatric disorders to be greater in such families compared to specific vulnerability to SS or affective psychosis. These findings may also have implications for provision of care for the probands.