CCH attack frequency reduction after psilocybin correlates with hypothalamic functional connectivity.

OBJECTIVE: To evaluate the feasibility and prophylactic effect of psilocybin as well as its effects on hypothalamic functional connectivity (FC) in patients with chronic cluster headache (CCH). BACKGROUND: CCH is an excruciating and difficult-to-treat disorder with incompletely understood pathophysiology, although hypothalamic dysfunction has been implicated. Psilocybin may have beneficial prophylactic effects, but clinical evidence is limited. METHODS: In this small open-label clinical trial, 10 patients with CCH were included and maintained headache diaries for 10 weeks. Patients received three doses of peroral psilocybin (0.14 mg/kg) on the first day of weeks five, six, and seven. The first 4 weeks served as baseline and the last 4 weeks as follow-up. Hypothalamic FC was determined using functional magnetic resonance imaging the day before the first psilocybin dose and 1 week after the last dose. RESULTS: The treatment was well tolerated. Attack frequency was reduced by mean (standard deviation) 31% (31) from baseline to follow-up (pFWER = 0.008). One patient experienced 21 weeks of complete remission. Changes in hypothalamic-diencephalic FC correlated negatively with a percent change in attack frequency (pFWER = 0.03, R = -0.81), implicating this neural pathway in treatment response. CONCLUSION: Our results indicate that psilocybin may have prophylactic potential and implicates the hypothalamus in possible treatment response. Further clinical studies are warranted.

Blood-brain barrier permeable ß-blockers linked to lower risk of Alzheimer's disease in hypertension.

Alzheimer's disease is a neurodegenerative disorder in which the pathological accumulation of amyloid-ß and tau begins years before symptom onset. Emerging evidence suggests that ß-blockers (ß-adrenergic antagonists) increase brain clearance of these metabolites by enhancing CSF flow. Our objective was to determine whether ß-blocker treatments that easily cross the blood-brain barrier reduce the risk of Alzheimer's disease compared to less permeable ß-blockers. Data from the Danish national registers were used to identify a retrospective cohort of individuals with hypertension, and those treated with ß-blockers were included in the analysis. People with indications for ß-blocker use other than hypertension (e.g. heart failure) were only retained in a sensitivity analysis. ß-blockers were divided into three permeability groups: low, moderate and high. We used multivariable cause-specific Cox regression to model the effect of ß-blocker blood-brain barrier permeability on time to dementia outcomes, adjusting for baseline comorbidities, demographics and socioeconomic variables. Death was modelled as a competing risk. The 10-year standardized absolute risk was estimated as the averaged person-specific risks per treatment. In a cohort of 69 081 (median age = 64.4 years, 64.8% female) people treated with ß-blockers for hypertension, highly blood-brain barrier-permeable ß-blockers were associated with reduced risk of Alzheimer's disease versus low permeability ß-blockers (-0.45%, P < 0.036). This effect was specific to Alzheimer's diagnoses and did not extend to dementia in general. Propensity score analysis matching high and low blood-brain barrier-permeable patients also detected a decreased Alzheimer's risk (-0.92%, P < 0.001) in the high permeability group compared to the low, as did a 1-year landmark analysis (-0.57%, P < 0.029) in which events within the first year of follow-up were ignored as likely unrelated to treatment. Our results suggest that amongst people taking ß-blockers for hypertension, treatment with highly blood-brain barrier permeable ß-blockers reduces the risk of Alzheimer's disease compared to low permeability drugs. Our findings support the hypothesis that highly permeable ß-blockers protect against Alzheimer's disease by promoting waste brain metabolite clearance.