A small open-label trial tested low doses of psilocybin (5, 7.5, and 10 mg) with psychological support in four patients with chronic short-lasting unilateral neuralgiform headache attacks (SUNHA), a severe headache disorder. The study was terminated early due to recruitment difficulties; three participants completed all sessions. No significant adverse events occurred. Cognitive testing during the acute drug experience was not possible because participants reported high subjective dose intensity. Headache impact remained severe throughout the trial. Mean daily attack frequency decreased by more than 50% in two participants at final follow-up. Thematic analysis of clinical notes suggested psychological insights, including reconfigured relationships to headache pain, were key features of participants' experience. The clinical results provide no conclusive evidence for psilocybin in SUNHA.
Functional neurological disorder (FND) is a common, debilitating condition linked to abnormal brain networks, dissociation, interoception, and motor agency. This open-label neuroimaging protocol will administer 25 mg of oral psilocybin with psychological support to 24 people with chronic FND. Resting-state and task-based functional MRI sequences will be compared before and after psilocybin. Additional measures include interoception, somatisation, illness perceptions, suggestibility, and dissociation. Participants will be followed for three months. The study aims to probe mechanisms underlying FND and assess the safety and feasibility of psychedelic administration with psychological support in this population.