Cerebrovascular Reactivity in Major Depression: A Pilot Study

OBJECTIVE: There are a growing number of reports that depression may increase the risk of stroke. Little is known, however, about the pathophysiologic mechanisms underlying this association. Cerebrovascular reactivity (CVR) reflects the compensatory dilatory capacity of cerebral arterioles to a dilatory stimulus and is an important mechanism to provide constant cerebral blood flow. We hypothesized that CVR is reduced in patients with major depression, thus contributing to the association between depression and stroke. METHODS: We assessed CVR in 33 patients with unipolar depression and 26 healthy controls by calculating the increase in cerebral blood flow velocity after stimulation with acetazolamide. Blood flow velocities were measured by transcranial Doppler ultrasound. RESULTS: Cerebrovascular reactivity was significantly reduced in depressed patients. Smoking was also associated with a significant reduction in CVR, whereas age and gender had no significant influence. CONCLUSIONS: Cerebrovascular reactivity appears to be impaired in major depression. Further studies should clarify the mechanisms leading to this reduced CVR.