Inter-rater reliability of family history information on psychiatric disorders in relatives

The family history method in psychiatric family studies is an important and necessary way of obtaining information on family members who are not available for personal interview. Studies on the validity of this method have shown that family history information on psychiatric disorders in relatives is neither accurate nor sensitive but highly specific. However, its inter-rater reliability has rarely been assessed, even though this is a prerequisite for adequate validity. In the present investigation we examined the inter-rater reliability of family history information obtained with a semi-structured and symptom-oriented interview. Forty informants were interviewed twice by two different raters within 3 and 20 days. The inter-rater reliability was found to be good for dementia (kappa=0.82, 95% CI=0.61-1.00), alcohol related disorders (kappa=0.93, 95% CI=0.80-1.00), for depressive disorders (kappa=0.72, 95% CI=0.42-1.00), anxiety disorders (kappa=0.75, 95% CI=0.41-1.00) and any psychiatric disorder (kappa=0.79, 95% CI=0.66-0.91). We concluded that the family history interview is a useful family study instrument that can be applied reliably by different raters for frequent psychiatric disorders.