Is cerebral blood flow altered by anxiety and depression in a sex-dependent manner?
Authors: Rogers Emily , Didier Kaylin D , Muer Jessica , Banks Nile F , Haley Travis , Wannebo Brett , Khademi Motlagh Hedyeh 
Published: May 2024

Background: It is well-known that premenopausal females have greater cerebral blood flow (CBF) than age-matched males. People with anxiety and/or depression (A/D) have altered CBF compared to those without A/D. For example, males with depression may have greater CBF, and females with depression may have lower CBF, than their healthy counterparts. In contrast, anxiety may be correlated with higher CBF in certain brain regions such as the amygdala and hippocampus in both sexes. However prior studies assessing the effect of sex and A/D on CBF did not control for the menstrual cycle, something which is known to influence CBF in females. Objective: To determine if A/D is linked to CBF alterations in young healthy adults, in a sex-specific pattern, while controlling for menstrual cycle and hormonal contraception (HC). Hypothesis: As most of our subjects had depression, we hypothesized that CBF would be higher in control (CON) females than CON males and this difference will be abolished in A/D subjects, due to a greater CBF in A/D males compared to CON males and a lower CBF in A/D females compared to CON females. Methods: Twenty females (4 A/D) and 21 males (8 A/D) had their CBF (ml/100gm/min) measured using magnetic resonance imaging (MRI, 3T) with arterial spin labelling (ASL). A/D was diagnosed by a physician. Subjects in all 4 groups were matched for age (mean ± SD; 21 ± 2 y). Females were studied during days 1-5 of the menstrual cycle and were not taking HC. CBF data were tested using 2-way mixed effects analyses (sex*group (i.e., CON vs. A/D)) in: grey matter (GM), white matter (WM), and 8 emotional/memory regions of the brain, including the accumbens, amygdala, caudate, anterior cingulate, hippocampus, entorhinal, parahippocampus, and precuneus. Results: A trend for significant sex*group interaction (all p ≥ 0.052) but not group main effects (all p ≥ 0.100) was observed. CBF in GM and WM as well as in the 8 emotional/memory regions was higher in females compared to males (main effect of sex, p ≤ 0.004). This sex effect appeared to be driven by the CON groups ( p < 0.0001 for all areas), as there were no CBF differences in any area between males and females in the A/D group (all p ≥ 0.089).Exploratory analyses showed significantly greater CBF in A/D males compared to CON males in GM as well as the accumbens, caudate, hippocampus, precuneus, and anterior cingulate gyrus (all p ≤ 0.049). No differences were observed for any outcome. Conclusion: These data suggest that while CON females have greater CBF than CON males at rest, this sex difference may be abolished in those with A/D. Albeit preliminary, these data are in line with previous findings whereby CBF appears to decrease more in females with depression and either remain unchanged or increase in males with depression. The higher CBF in certain regions in A/D males is interesting and in line with previous research showing increased CBF in the hippocampus with anxiety. As our sample size was small and included a mix of people with either anxiety or depression, future research should be conducted to assess the differential effects of these conditions in young adults. Support by NIH (HL150361). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.