Sympathetic reactivity to emotional stress in women with major depressive disorder.

Young women, who suffer from major depressive disorder (MDD) at twice the rate as young men, are particularly vulnerable to cardiovascular events triggered by emotional stress, an association that may be partially explained by excessive sympathetic activation. However, no studies have directly measured sympathetic activity during acute emotional stress in young women with MDD. We hypothesized that the muscle sympathetic nerve activity (MSNA) response to acute emotional stress would be greater in young women with MDD (18-30 yrs) compared to healthy non-depressed young women. MSNA (peroneal microneurography) and beat-to-beat blood pressure (BP; finger photoplethysmography) were measured at rest and during acute emotional stress evoked by viewing negative images selected from the International Affective Picture System in 17 healthy young women and in 30 young women with MDD of mild-to-moderate severity (unmedicated). There were no group differences in either the peak increase in MSNA (Δ0.1 ± 2.9 healthy vs. Δ2.0 ± 4.9 bursts/min MDD; p = 0.45) or the peak increase in mean arterial pressure (Δ0.6 ± 3.5 healthy vs. Δ1.4 ± 2.1 mmHg MDD; p = 0.67) in response to viewing negative images. However, in young women with MDD, MSNA reactivity to viewing negative images was positively related to current depressive symptom severity (r = 0.49; p = 0.04). Although these data indicate only minor MSNA responses to viewing negative images, they also highlight that sympathetic-cardiovascular reactivity to an acute, passive emotional stress stimulus is not exaggerated in young women with MDD. However, more severe current depressive symptoms may amplify emotional stress-induced sympathetic activation, thereby increasing cardiovascular risk.