Transdiagnostic Assessment of Psychopathology: Psychometric Evaluation of the German Version of the Defense Mechanism Rating Scale (DMRS-SR-30) and Relationship with Personality Functioning and Associated Constructs.

Defense mechanisms are relevant transdiagnostic markers for adaptive and maladaptive personality functioning and psychopathology. This study investigates the factor structure, reliability and convergent and discriminant validity of the German version of the novel Defense Mechanism Rating Scales-Self Report-30 (DMRS-SR-30). Data was collected from a German community-based sample (N = 584) and a second independent sample of clinical (n = 30) and non-clinical (n = 30) participants. Confirmatory factor analysis showed that the three-factor structure proposed by Prout et al. could not be replicated. Subsequent exploratory factor analysis revealed a three-factor solution (Mature, Mental-Inhibition-and-Avoidance, Immature-Depressive) with diverging item loading compared to previous findings. Correlation analyses supported the construct validity of the scale: Mature defenses showed significant negative correlations with impairment in personality functioning (assessed with the Levels of Personality Functioning Scale (LPFS): r = -0.60) and maladaptive personality traits (assessed with the Personality Inventory for DSM-5 (PID5BF + M): r = -0.33 - -0.57). Regarding discriminative validity, the clinical group scored significantly lower on mature defense mechanisms (d = 0.64) and significantly higher on neurotic defense mechanisms (d = 0.55-0.97) compared to the non-clinical group. Implications for the German version of the DMRS-SR-30 and future research are discussed.