Patterns of adaptation in obsessive-compulsive disorder: Multivariate indicators of greater variability and linear change compared to controls

Patterns of adaptation to conflict in persons with Obsessive-Compulsive Disorder were assessed with the Serial Color-Word Test. Obsessive-Compulsive patients (n=50) were compared with an age-and sex-matched group of nonclinical volunteers. Measures of linear and nonlinear change in reading times during each of the five consecutive trials of the test were compared between groups by means of a multivariate model with doubly repeated measures. The multivariate analysis yielded a significant between-groups result (Wilks Lambda=.76, p<.001), mainly supported by higher values of nonlinear change in the Obsessive-Compulsive group. Thus, the discriminative ability of the Serial Color-Word Test was confirmed when individual differences were removed from the error term.