Disorders of this nature are often caused by a mix of both environmental and biological factors. Environmental stressors have also been found to prospectively increase risk for PMDD symptoms. Genetics do not operate in a vacuum: environmental components such as stress, hormonal fluctuation, and epigenetics play a key role in the pathology and onset of the disorder. Some studies have noted evidence of interpersonal trauma (domestic violence, physical or emotional trauma, or substance abuse) or seasonal changes (making PMDD potentially comorbid with Seasonal Affective Disorder) having an impact on PMDD risk. But the most common pre-existing disorder found in those diagnosed with PMDD is major depression, wherein they either actually had it or were misdiagnosed when they should have only been diagnosed with PMDD. The last environmental factor is primarily sociological: the sociocultural aspects of being female, performing female gender roles, and stress from engaging in female sexual activity.