Classic psychedelics like LSD, psilocybin, ayahuasca, and mescaline act mainly on 5-HT2A receptors and are being studied as treatments for psychiatric disorders, including alcohol use problems. This systematic review analyzed 27 studies (20 human, 7 preclinical) published between 2000 and 2021. Human studies generally suggest that classic psychedelics could help reduce alcohol consumption, but many have methodological limitations such as small sample sizes or lack of control groups. Preclinical studies are scarce and show conflicting results. Psilocybin shows the most consistent data as a potential candidate for treating alcohol use disorders. More rigorous studies are needed to understand the underlying mechanisms.
Parkinson's disease involves progressive loss of dopamine-producing neurons in the nigrostriatal pathway, along with brain inflammation. Current medications only manage symptoms. This preclinical study tested N,N-dimethyltryptamine (DMT), the active compound in ayahuasca, which activates serotonin 5-HT2A receptors (causing hallucinogenic effects) and sigma-1 receptors linked to neuroprotection. DMT treatment produced molecular changes in the nigrostriatal pathway indicating reduced neuroinflammation and preserved neurons. Behavioral tests also showed symptom improvement. These results suggest DMT may modify disease progression in Parkinson's disease, supporting further research.