Bidirectional analysis of the association between migraine and post-traumatic stress disorder in Nurses' Health Study II.

Aims: Migraine and post-traumatic stress disorder (PTSD) are both twice as common in women as men. Cross-sectional studies have shown associations between migraine and several psychiatric conditions, including PTSD. PTSD is disproportionally common among patients in headache clinics, and individuals with migraine and PTSD report greater disability from migraines and more frequent medication use. To further clarify the nature of the relationship between PTSD and migraine, we conducted bidirectional analyses of the association between (1) migraine and incident PTSD and (2) PTSD and incident migraine.

Methods: We used longitudinal data from 1989-2020 among the 33,327 Nurses' Health Study II respondents to the 2018 stress questionnaire. We used log-binomial models to estimate the relative risk of developing PTSD among women with migraine and the relative risk of developing migraine among individuals with PTSD, trauma-exposed individuals without PTSD, and individuals unexposed to trauma, adjusting for race, education, marital status, high blood pressure, high cholesterol, alcohol intake, smoking, and body mass index.

Results: Overall, 48% of respondents reported ever experiencing migraine, 82% reported experiencing trauma and 9% met the Diagnostic and Statistical Manual of Mental Disorders-5 criteria for PTSD. Of those reporting migraine and trauma, 67% reported trauma before migraine onset, 2% reported trauma and migraine onset in the same year and 31% reported trauma after migraine onset. We found that migraine was associated with incident PTSD (adjusted relative risk [RR]: 1.26, 95% confidence interval [CI]: 1.14-1.39). PTSD, but not trauma without PTSD, was associated with incident migraine (adjusted RR: 1.20, 95% CI: 1.14-1.27). Findings were consistently stronger in both directions among those experiencing migraine with aura.

Conclusions: Our study provides further evidence that migraine and PTSD are strongly comorbid and found associations of similar magnitude between migraine and incident PTSD and PTSD and incident migraine.