Prevalence of dementia in a rural Netherlands population and the influence of DSM-III-R and CAMDEX criteria for the prevalence of mild and more severe forms.

To obtain estimates of the prevalence of mild and moderate/severe dementia among people age 65 and over, applying criteria for severity of both DSM-III-R and CAMDEX, a two-stage community-based study was conducted in a rural area of the Netherlands. In the first stage, 2191 subjects (out of the target population of 2655) participated in an interview which included the Mini-Mental State Examination (MMSE). Based on MMSE score, a non-proportional random sample (n=496) was drawn for the second stage. A total of 421 subjects responded and were subsequently examined using the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX). In determining the severity of dementia, criteria of both DSM-III-R and CAMDEX were applied. Overall prevalence for both classification systems was 6.5%. There was a large discrepancy between the two classification systems with regard to the criteria for rating severity. The prevalence of moderate/severe dementia using DSM-III-R criteria was twice as high as the prevalence using CAMDEX criteria. These findings reflect the differences between DSM-III-R and CAMDEX in descriptions of dementia severity. Rating according to CAMDEX predicts institutionalization in specialized nursing homes somewhat better than staging according to DSM-III-R. Both content analysis and institutionalization data suggest that the CAMDEX operationalization of rating severity seems preferable.