Age-neutrality of DSM-IV Axis II criteria over the life-span:
Drs. Inge Debast (VUB), Prof. Dr. Gina Rossi (VUB), Prof. Dr. Bas Van Alphen (Mondriaan/VUB), & Prof. Dr. Dierckx (VUB/Alexianen).
Self-report questionnaires are regularly used to assess personality, and are a tool in diagnosing personality pathology over the life span. However, reliability of self-report in older compared to younger age groups can be limited due to aspects of aging. Furthermore, the life context is barely considered in the formulation of DSM-IV personality disorder criteria. This lack of age neutral criteria hampers a valid assessment of personality pathology when applied to older age groups. Therefore we examined the age-neutrality of the Assessment of DSM-IV Personality disorders (ADP-IV; Schotte & De Doncker, 1994). Although this instrument is well validated, the validity for use across different age groups is not empirically examined up to now. In search of potential age bias, we conducted Differential Item Functioning (DIF) analyses on the dimensional trait scales and items of the ADP-IV. We examined whether subjects from different age groups, but with a comparab
le level of pathology, have different probabilities of endorsing an item (=measurement bias). Initial results suggested that the vast majority (97%) of the trait items are measured equally well across age, which is a considerable better result than a previous study which showed a bias of 29% in the DSM-IV criteria on basis of interviews. Differential Test Functioning (DTF) analyses confirmed no significant impact of DIF results on scale level. Methodological and conceptual issues concerning the clinical use of the APP-IV across younger and older age groups will be discussed, as well as implications for research regarding age differences in personality disorder prevalence rates.