toms worsen. Symptoms cease after menopaus e, although cyclical hormone replacement
can trigger the re-expression of symptoms.
Risk and Prognostic Factors 
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 prem enstrual dysphoric disorder is unknown.
However, for premenstrual sy mptoms, estimates for heritability range between 30% and
80%, with the most stable component of premenstrual symptoms es timated to be about
50% heritable. 
Course modifiers. Women who use oral contraceptiv es may have fewer premenstrual
complaints than do women who do not use oral contraceptives. 
Culture-Related Diagnostic Issues
Premenstrual dysphoric disord er 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, fr equency, intensity, and expres sivity of symptoms and help-
seeking patterns may be significantl y influenced by cultural factors. 
Diagnostic Markers
As indicated earlier, the diagnosis of premenstrual dysphoric disorder is appropriately
confirmed by 2 months of pros pective symptom ratings. A number of scales, including the