A 28-year-old female reports severe irritability, mood lability, anxiety, and difficulty concentrating that consistently begin approximately 7 days before menses onset and resolve within a few days after menses begins. She has tracked her symptoms with a daily rating chart for 3 consecutive menstrual cycles at the request of her gynecologist. She reports that symptoms significantly impair her work performance and interpersonal relationships during the luteal phase. She denies symptoms during the follicular phase and has no history of a mood or anxiety disorder. Which factor is most critical to confirm a diagnosis of premenstrual dysphoric disorder (PMDD)?