Women's vulnerability for a first lifetime-onset of major depressive disorder (MDD) during midlife is substantial. It is unclear whether risk factors differ for first lifetime-onset and recurrent MDD. Identifying these risk factors can provide more focused depression screening and earlier intervention. This study aims to evaluate whether lifetime psychiatric and health histories, personality traits, menopausal status and factors that vary over time, e.g. symptoms, are independent risk factors for first-onset or recurrent MDD across 13 annual follow-ups.

Four hundred and forty-three women, aged 42–52 years, enrolled in the Study of Women's Health Across the Nation in Pittsburgh and participated in the Mental Health Study. Psychiatric interviews obtained information on lifetime psychiatric disorders at baseline and on occurrences of MDD episodes annually. Psychosocial and health-related data were collected annually. Cox multivariable analyses were conducted separately for women with and without a MDD history at baseline.

Women without lifetime MDD at baseline had a lower risk of developing MDD during midlife than those with a prior MDD history (28% v. 59%) and their risk profiles differed. Health conditions prior to baseline and during follow-ups perception of functioning (ps < 0.05) and vasomotor symptoms (VMS) (p = 0.08) were risk factors for first lifetime-onset MDD. Being peri- and post-menopausal, psychological symptoms and a prior anxiety disorder were predominant risk factors for MDD recurrence.

The menopausal transition warrants attention as a period of vulnerability to MDD recurrence, while health factors and VMS should be considered important risk factors for first lifetime-onset of MDD during midlife.

Little is known about factors that predict first lifetime episodes of major depression in middle-aged women. It is not known whether health-related factors and life stress pose more or less of a risk to the onset of clinical depression than does the menopausal transition.

The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to assess diagnoses of lifetime, annual and current major depression in a community-based sample of premenopausal or early perimenopausal African American and White women. Menstrual cycle characteristics, psychosocial and health-related factors, and blood samples for assay of reproductive hormones were obtained annually. Two hundred and sixty-six women without a history of major depression at baseline constituted the cohort for the current analyses.

Over 7 years of follow-up, 42 (15.8%) women met criteria for a diagnosis of major depression. Frequent vasomotor symptoms (VMS; hot flashes and/or night sweats) (HR 2.14, p=0.03) were a significant predictor of major depression in univariate analyses. After simultaneous adjustment for multiple predictors in Cox proportional hazards analyses, frequent VMS were no longer significant; lifetime history of an anxiety disorder (HR 2.20, p=0.02) and role limitations due to physical health (HR 1.88, p=0.07) at baseline and a very stressful life event (HR 2.25, p=0.04) prior to depression onset predicted a first episode of major depression.

Both earlier (e.g. history of anxiety disorders) and more proximal factors (e.g. life stress) may be more important than VMS in contributing to a first episode of major depression during midlife.