Establishing the diagnostic validity of premenstrual dysphoric disorder using rasch analysis.

Premenstrual Dysphoric Disorder (PMDD) has remained in appendices of the last two editions of The Diagnostic and Statistical Manual of Mental Disorders due to lack of empirical study. Items included in its set of research criteria are considered tentative pending evidence of diagnostic validity. The present study attempts to establish the construct validity of the PMDD criteria using the Rasch method to analyze the validity of individual items as contributors to the diagnosis, in contrast to the usual but less precise approach of using an external validator to establish the diagnostic utility of psychiatric conditions. Analysis of which items best differentiate participants with and without PMDD provides an idea of the relative ability of these items to distinguish PMDD. It is recommended that the areas of anger/irritability, depressed mood, and problems in interpersonal functioning be expanded in further studies and corresponding items added to symptom checklists.