SUBJECT AND INFORMANT VARIABLES AFFECTING FAMILY HISTORY DIAGNOSES OFDEPRESSION AND DEMENTIA

The aim of the present study was to evaluate subject and informant fac tors affecting the validity of the family history for dementia and dep ression. Relatives of patients and control subjects (n = 531) were int erviewed directly. At least one 'significant' other provided family hi story information on every interviewed relative. The detection of deme ntia or depression based on the family history increased with the seve rity of the respective disorder. The likelihood of detecting dementia based on the family history increased in proportion to the subject's a ge. A lifetime diagnosis of depression in the informant improved the d etection of this disorder in a relative. The presence of another psych iatric disorder in either the interviewed relative or the informant si gnificantly increased the risk for false-positive diagnoses of depress ion. The present results demonstrate that family history information o n depression and dementia is influenced by different proband and infor mant variables. On the basis of these results, we cannot recommend red ucing thresholds for family history diagnoses. (C) 1997 Elsevier Scien ce Ireland Ltd.