Researchers tested whether people with severe depression could take psilocybin (a compound from certain mushrooms) while staying on their antidepressant medications. In this study of 19 people, those who received psilocybin with psychological support while continuing their SSRI showed significant improvement in depression symptoms over three weeks, with response rates of 42%. Side effects were mostly mild and temporary, suggesting this approach may be safe and effective without requiring patients to stop their current antidepressants.