Additional Study Information: We are currently enrolling individuals with significant and distressing body image concerns to participate in a research study that will assess whether a single dose of psilocybin may be a safe and effective treatment to improve appearance-related worries. Individuals may be eligible if they are not currently on psychiatric medications and have tried an anti-depressant (SSRI, SNRI, or Clomipramine) in the past. For eligible participants, the research study will involve 1 visit that is around 8 hours during which they will receive psilocybin with the support of a therapist. Participants will then return for follow-up visits over the course of 12 weeks. The study will also assess the effect of the treatment on brain activity using a scan called magnetic resonance imaging (MRI). Participants will receive compensation for completing the study.