Research suggests psilocybin may have potential as a treatment for OCD. Psilocybin interacts with different serotonin receptors in the brain, including those which appear to regulate certain brain regions with increased activity in individuals with OCD1 . Multiple doses of psilocybin may change the binding activity of serotonin receptors in such a way that OCD symptoms are reduced.
Psilocybin may also alleviate doubt and rumination, two key elements underlying obsessions, which may be measured through assessment of a specific brainwave pattern that increases in those with symptomatic OCD. Recent research shows that psilocybin alters functional connectivity between and within different brain regions2 . One particular brain region, known as the Default Mode Network (DMN), is highly involved in self-referential thinking and is shown to increase connectivity and activity in individuals with OCD. Psilocybin treatments may dramatically change and reset functional connectivity in DMN structures and lead to reduced OCD symptoms.
While research is still limited, one 2006 study looking at psilocybin as a possible treatment for OCD assessed nine patients with moderate-to-severe OCD. Patients received three escalating doses of psilocybin ranging from 7mg to 21mg each separated by at least a week. A very low dose of 1.75mg of psilocybin was inserted randomly in a double-blind manner at any point after the first dose. After a 24-hour window of monitoring post-administration, all patients experienced marked relief from symptoms after one psilocybin session. Two patients reported symptomatic relief lasting nearly a week, with one patient remaining in remission at a 6-month follow-up3 .