Cerebrovascular reactivity is blunted in young adults with major depressive disorder: The influence of current depressive symptomology

Background: In middle-aged adults with depression, cerebral vasodilatory reactivity is blunted; however, this has not been examined in treatment-naive young adults with major depressive disorder (MDD). We tested the hypothesis that cerebrovascular reactivity would be blunted in young adults (18-30 yrs) with MDD compared to healthy non-depressed adults (HA) and would be attenuated to a greater extent in adults with symptomatic MDD (sMDD) compared to adults with MDD in remission (euthymic MDD; eMDD). Methods: Sixteen adults with MDD [21 +/- 3yrs; n = 8 sMDD (6 women); n = 8 eMDD (5 women)] and 14 HA (22 +/- 3yrs; 9 women) participated. End-tidal carbon dioxide concentration (PETCO2; capnograph), beat-to-beat mean arterial pressure (MAP; finger photoplethysmography), middle cerebral artery blood velocity (MCAv; transcranial Doppler ultrasound), and internal carotid artery (ICA) diameter and blood velocity (Doppler ultrasound) were continuously measured during baseline and rebreathing-induced hypercapnia. Cerebrovascular reactivity was calculated as the relative increase in vascular conductance during hypercapnia. Results: In adults with MDD, cerebrovascular reactivity in the MCA (.39 +/- 9 HA vs..31 +/- 13% MDD, p = 0.04), but not the ICA (.36 +/- 24 HA vs..34 +/- 18% MDD, p = 0.84), was blunted compared to HA. In the MCA, cerebrovascular reactivity was reduced in adults with sMDD compared to adults with eMDD (.36 +/- 11 eMDD vs..25 +/- 13% sMDD, p = 0.02). Limitations: The cross-sectional nature approach limits conclusions regarding the temporal nature of this link. Conclusion: These data indicate that MCA cerebrovascular reactivity is blunted in young adults with MDD and further modulated by current depressive symptomology, suggesting that the management of depressive symptomology may secondarily improve cerebrovascular health.