Psychological factors and premenstrual syndrome: A Spanish case-control study

Objective To assess whether the psychological variables perceived stress, neuroticism and coping strategies, are associated with Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Syndrome (PMDD). Design Case-control study with incident cases using the Spanish public healthcare system. Setting 3 major public hospitals and one family counseling and planning center. Population Women consulting for troubles related to menstruation and for other motives such as screening for uterine cancer, contraception counselling or desire for pregnancy. Methods Logistic regression. Main outcome measures Odds of PMS and PMDD. Results 285 PMS and 285 age-matched controls, as well as 88 PMDD cases and 176 controls participated in the study. Medium and high levels of perceived stress were associated with an increase in the odds of PMS (Odds Ratio (OR) = 2.49; 95% CI: 1.41-4.39 and OR = 4.90; 95% CI: 2.70-8.89, respectively). For PMDD the results were: OR = 2.61; 95% CI: 1.35-5.05 and OR = 5.79; 95% CI: 2.63-12.76, respectively. Subjects with medium and high levels of neuroticism were also at higher odds of suffering from PMS (OR = 2.53; 95% CI: 1.06-6.06 and OR = 8.05; 95% CI: 3.07-2.12, respectively). For PMDD, the results were OR = 3.70; 95% CI: 1.27-10.77 and 5.73: 95% CI: 1.96-16.77, respectively. High levels in the large majority of coping strategies were also associated with increased odds of PMS and PMDD. Conclusions Psychological factors including perceived stress, neuroticism and coping strategies are strongly related to PMS/PMDD. This association is unlikely to be due to confounding or misclassification bias. A reverse causation process cannot be ruled out although its likelihood is remote.