Twelve-month prevalence of premenstrual dysphoric disorder is between 1.8% and 5.8% of menstruating women. Estimates are substantially inﬂated if they are based on retro- spective reports rather than prospective daily ratings. However, estimated prevalence based on a daily record of symptoms for 1—2 months may be less representative, as indi- viduals with the most severe symptoms may be unable to sustain the rating process. The most rigorous estimate of premenstrual dysphoric disorder is 1.8% for women whose symptoms meet the full criteria without functional impairment and 1.3% for women whose symptoms meet the current criteria with functional impairment and without co-oc- curring symptoms from another mental disorder.
Onset of premenstrual dysphoric disorder can occur at any point after menarche. Inci- dence of new cases over a 40-month follow-up period is 2.5% (95% confidence interval = 1.7—3.7). Anecdotally, many individuals, as they approach menopause, report that symp- toms worsen. Symptoms cease after menopause, although cyclical hormone replacement can trigger the re-expression of symptoms.
Environmental. Environmental factors associated with the expression of premenstrual dysphoric disorder include stress, history of interpersonal trauma, seasonal changes, and sociocultural aspects of female sexual behavior in general, and female gender role in par- ticular.
Genetic and physiological. Heritability of premenstrual dysphoric disorder is unknown.
However, for premenstrual symptoms, estimates for heritability range between 30% and 80%, with the most stable component of premenstrual symptoms estimated to be about 50% heritable.
Course modifiers. Women who use oral contraceptives may have fewer premenstrual complaints than do women who do not use oral contraceptives.
Premenstrual dysphoric disorder is not a culture-bound syndrome and has been observed in individuals in the United States, Europe, India, and Asia. It is unclear as to whether rates differ by race. Nevertheless, frequency, intensity, and expressivity of symptoms and help- seeking patterns may be significantly inﬂuenced by cultural factors.
As indicated earlier, the diagnosis of premenstrual dysphoric disorder is appropriately confirmed by 2 months of prospective symptom ratings. A number of scales, including the
Daily Rating of Severity of Problems and the Visual Analogue Scales for Premenstrual
Mood Symptoms, have undergone validation and are commonly used in clinical trials for premenstrual dysphoric disorder. The Premenstrual Tension Syndrome Rating Scale has a self—report and an observer version, both of which have been validated and used widely to measure illness severity in women who have premenstrual dysphoric disorder.
Symptoms must be associated with clinically meaningful distress and/ or an obvious and marked impairment in the ability to function socially or occupationally in the week prior to menses. Impairment in social functioning may be manifested by marital discord and problems with children, other family members, or friends. Chronic marital or job prob- lems should not be confused with dysfunction that occurs only in association with pre- menstrual dysphoric disorder.
Premenstrual syndrome. Premenstrual syndrome differs from premenstrual dysphoric disorder in that a minimum of five symptoms is not required, and there is no stipulation of affective symptoms for individuals who have premenstrual syndrome. This condition may be more common than premenstrual dysphoric disorder, although the estimated prevalence of premenstrual syndrome varies. While premenstrual syndrome shares the feature of symptom expression during the premenstrual phase of the menstrual cycle, it is generally considered to be less severe than premenstrual dysphoric disorder. The pres- ence of physical or behavioral symptoms in the premenstruum, without the required affective symptoms, likely meets criteria for premenstrual syndrome and not for premen- strual dysphoric disorder.