Die deutschsprachige Fassung des Muscle Dysmorphia Inventory: Evaluation der psychometrischen Kennwerte in männlichen Stichproben

To assess central aspects of muscle dysmorphia, classified as a subtype of body dysmorphic disorder, the Muscle Dysmorphia Inventory (MDI) is available for the English-speaking areas. The aim of the present study was to evaluate the psychometric properties of the German-language version of the MDI. Therefore, male participants from two separate samples (sample 1: n=143; sample 2: n=71; N=214) completed a questionnaire battery, including the MDI. Using confirmatory factor analysis, the factor structure postulated by the authors of the English-language original version could not be replicated. However, the fit indices were broadly adequate when the model was altered based on the modification indices. The MDI subscales showed acceptable to excellent internal consistencies. The test-retest reliability of approximately 14 days was high. Significant positive correlations of the MDI subscales with other body image and psychopathology measures, and the weight-training frequency per week indicated good convergent and criterion validity. Furthermore, the MDI differentiated between subgroups of men with muscle dysmorphia, weight-training, and non-weight-training men. With the exception of the subscale Pharmacological Use (PU), which showed lower reliability and validity, and the insufficient model fit, the German-language version of the MDI generally displayed adequate psychometric properties. Hence, with restrictions concerning the subscale PU, the administration in clinical-psychological research and a psychotherapeutic context seems to be recommendable.