Assessment of cerebrovascular reactivity during major depression and after remission of disease

BACKGROUND: There are a growing number of studies suggesting that depression may increase the risk of stroke. Impaired autoregulation of vascular tone may contribute to a higher risk of developing cerebrovascular diseases. Cerebrovascular reactivity (CVR) reflects the compensatory dilatory capacity of cerebral arterioles to a dilatory stimulus and is an important mechanism that ensures constant cerebral blood flow. There is a hypothesis that CVR is reduced in major depression, which would explain the association between depression and stroke. OBJECTIVES: The aim of this study was to investigate the effect of depression on CVR in cerebral vessels by comparing CVR during the depression phase with that during remission. MATERIAL AND METHODS: Using the apnea test, we assessed CVR in 16 patients with unipolar depression during disease and after remission of disease by calculating the increase in cerebral blood flow velocity after breath-holding (the apnea test). Blood flow velocities were measured by transcranial Doppler ultrasound (TCD). RESULTS: CVR was significantly reduced in the depression phase in comparison to that in the remission phase. However, this change was not seen in all the patients. CONCLUSION: CVR was reduced in most of the depressed patients. The decreased CVR, as indicated by the changes in peak systolic velocity (PSV) and mean flow velocity (MFV) of the middle cerebral artery, in depressed patients was more marked on the right side, which could point to a vascular basis for some kinds of depression. We recommend that other studies, with larger samples, be done; future studies should assess whether the changes in the CVR varies with the severity and type of depression.