The diagnosis of substance-induced mental disorder lacks specificity. Understanding how ayahuasca acts on the brain—its pharmacodynamic properties—enables a more physiology-based approach to diagnosing a patient's condition.
Classic psychedelics such as LSD, psilocybin, mescaline, and ayahuasca are being studied again for treating unipolar and bipolar depression. They alter sensory perception, emotion, and self-processing by stimulating serotonin 2A receptors in the brain. Psychedelic-assisted psychotherapy integrates a safe psychedelic experience into ongoing therapy. Early randomized trials with psilocybin show promising results for unipolar depression, but classic psychedelics may also trigger mania. Atypical psychedelics like MDMA and ketamine work through different mechanisms; esketamine is approved for treatment-resistant unipolar depression, and ketamine shows early evidence for bipolar depression. Larger trials and careful legal frameworks will determine their broader clinical use.