Objective: The aim of the present study was to characterize the utility of family history data for predicting psychiatric and functional status in first-episode psychosis (FEP) during the pre-treatment phase of illness, at first presentation, and at 18 months follow up.
Method: An epidemiological study based upon a consecutive file audit of 661 patients admitted to the Early Psychosis Prevention and Intervention Centre between January 1998 and December 2000 using a standardized questionnaire.
Results: In the total sample of FEP patients family history was not significantly associated with psychiatric or functional status pre-treatment, at first presentation, or at 18 months. Male patients with a family history of psychotic illness had a longer duration of prodrome compared to those with no family history of psychiatric illness (mean=481.4 days, SD=678.0 vs mean=383.5 days, SD=524.7; p=0.03). Family history of non-psychotic illness was associated with comorbidity at first presentation in female patients, both for substance-use related comorbidity (p=0.02) and non-substance-use related comorbidity (p=0.03). There was substantial agreement between clinician reports of family history of psychosis and those obtained using a structured interview instrument (kappa=0.69, 95% confidence interval (CI)=0.41-0.86), but agreement for non-psychotic family history was comparatively low (kappa=0.28, 95%CI:=-0.03 to 0.52).
Conclusions: There are gender differences in the association between substance use disorder, duration of prodrome and family history. This supports the hypothesis that psychotic illness manifests differently in men and women. In the present sample, reports of family history of non-psychotic illness had lower convergent validity than reports of psychotic illness. The present reported associations with non-psychotic family history should therefore be interpreted with caution. Information on gender and family history of psychiatric illness may assist clinical diagnosis and determination of treatment in FEP patients, especially if specific familial risk factors can be identified.