Psychiatric and sociodemographic predictors of attrition in a longitudinal study: The Netherlands Mental Health Survey and Incidence Study (NEMESIS)

Abstract

This article discusses the effects of sociodemographics and the presence of psychiatric disorders diagnosed in the 12 months before the first interview by using the Diagnostic and Statistical Manual of Mental Disorders: DSM-III-R, third edition, revised, on three types of attrition (failure to locate, refusal to participate, morbidity/mortality) in the second wave (1997-1998) of the Netherlands Mental Health Survey and Incidence Study, a longitudinal, general population survey of psychopathology among 7,076 subjects aged 18-64 years. Compared with those reinterviewed successfully, persons not located at the 1-year follow-up (n = 219) were more often younger, poorly educated, urban, not cohabiting with a steady partner, and born outside the Netherlands. Refusers (n = 923) had a lower educational level. Morbidity/mortality (n = 72) was associated with higher age, lower educational level, not being employed, and somatic disorders. After adjustment for sociodemographics, none of the disorders was positively associated with refusal. Failure to locate was linked to agoraphobia, alcohol abuse, and the categories of mood, substance use, and eating disorders. Morbidity/mortality was linked to dysthymia, agoraphobia, simple phobia, obsessive-compulsive disorder, and the category of anxiety disorders. Overall attrition was only slightly higher among respondents with one or more disorders (odds ratio = 1.20, 95% confidence interval: 1.04, 1.38). Thus, psychopathology has only weak-to-moderate effects on attrition and is mainly related to failure to locate and morbidity/mortality but not to refusal.