Inter-informant agreement on diagnoses and prevalence estimates of anxiety disorders: Direct interview versus family history method

The aims of the present study were to: (1) assess agreement for diagnoses of specific anxiety disorders between direct interviews and the family history method; (2) compare prevalence estimates according to direct interviews and family history information; (3) test strategies to approximate prevalence estimates according to family history reports to those based on direct interviews; (4) test covariates of inter-infomant agreement; and (5) test the likelihood of reporting disorders by informants. Analyses were based on family study data which included 1625 distinct informant (first-degree relatives and spouses)-index subject pairs. Our main findings were: (1) inter-informant agreement was satisfactory for panic disorder, agoraphobia, social phobia and obsessive-compulsive disorder; (2) the family history method provided lower prevalence estimates for all anxiety disorders (except for generalized anxiety disorder and obsessive-compulsive disorder) than direct interviews; (3) the lowering of diagnostic thresholds and the combination of multiple family history reports increased the accuracy of prevalence estimates according to the family history method; (4) female gender of index subjects was associated with poor agreement; and (5) informants, who themselves had a history of an anxiety disorder, were more likely to detect this disorder in their relatives which entails the risk of overestimation of the size of familial aggregation. (c) 2006 Elsevier Ireland Ltd. All rights reserved.