LSD, a semi-synthetic hallucinogen first synthesized in 1938, was briefly used in psychiatry for alcoholism, neurosis, and psychosomatic disorders before its international prohibition in the 1970s. This non-systematic review found evidence that LSD may help treat drug and alcohol dependence and anxiety associated with life-threatening diseases. Modern neuroimaging shows LSD alters brain blood flow, electrical activity, and network communication patterns. Preclinical evidence indicates psychedelics affect neuroplasticity after both acute and chronic administration. When administered safely in a supervised psychotherapeutic setting, LSD may have potential for certain psychiatric conditions, warranting larger controlled studies.
Ayahuasca, a hallucinogenic tea containing monoamine oxidase inhibitors and DMT, shows potential benefits for psychiatric symptoms such as depression, anxiety, and drug addiction. In a randomized placebo-controlled trial, ayahuasca had a significant antidepressant effect compared to placebo. Long-term use was associated with structural brain alterations in medial regions, with no evidence of increased psychopathology or impaired neuropsychological functioning. Prolonged psychotic reactions among users are rare, and causal links to ayahuasca are difficult to establish. More controlled double-blinded studies with larger populations are needed to clarify therapeutic potentials and side effects.