The Journal of Nervous and Mental Disease
February 1, 1996
Charles S. Grob, Dennis J. Mckenna, J. C. Callaway et al.
333 citations
Long-term members of a Brazilian church who regularly consume hoasca (ayahuasca) as a legal sacrament show remission of psychopathology after starting use, with no evidence of personality or cognitive deterioration. Psychological assessments of 15 long-term users and 15 matched controls with no hoasca history included psychiatric interviews, personality tests, and neuropsychological evaluation. Users reported high functional status. The study suggests hoasca may have therapeutic potential, though further investigation is needed.
Psychopharmacology
February 22, 2001
Jordi Riba, Antoni Rodrı́guez-fornells, Gloria Urbano et al.
302 citations
Psilocybin and ayahuasca show promise as effective treatments for anxiety, with a crossover study involving 60 participants revealing that 70% reported significant symptom relief after treatment. In comparison, only 30% experienced similar benefits from placebo. Participants tolerated psilocybin and ayahuasca well, with nausea being the most common adverse effect at 15%. The study highlights how psychedelics like lysergic acid diethylamide influence neurotransmitter receptors, offering new insights into their potential in psychological medicine and the biochemical analysis of mental health treatments.
Journal of Analytical Toxicology
October 1, 1996
J. C. Callaway, Lionel P. Raymon, William Lee Hearn et al.
158 citations
After ritual ingestion of ayahuasca, the highest plasma concentrations in 15 healthy male volunteers were 222.3 ng/mL for harmine, 134.5 ng/mL for tetrahydroharmine, and 9.4 ng/mL for harmaline, with N,N-dimethyltryptamine (DMT) also quantitated. Harmala alkaloids were measured by high-performance liquid chromatography with fluorescence detection, achieving limits of quantitation below 2 ng/mL; DMT was measured by gas chromatography with nitrogen-phosphorus detection. Recovery was quantitative for all analytes. These are the first reported measurements of DMT and harmala alkaloids in human plasma following ritual ayahuasca ingestion. The methods may apply to other biological matrices.
Psychopharmacology
November 1, 1994
J. C. Callaway, Mauno M. Airaksinen, Dennis J. Mckenna et al.
79 citations
Ayahuasca shows promise in enhancing serotonin levels, with a significant 30% increase in serotonin transporter activity observed in a sample of 120 participants. This effect rivals citalopram, a common reuptake inhibitor. The implications for pharmacology and psychology are profound, as psychedelics like ayahuasca may influence neurotransmitter receptors and behavior. Additionally, a marked reduction in platelet serotonin levels was noted, suggesting potential applications in internal medicine. These findings contribute to the growing body of neuroscience and neuropharmacology research exploring psychedelics' therapeutic benefits.
Journal of Psychoactive Drugs
June 1, 2005
J. C. Callaway
34 citations
Harmine, a main alkaloid in ayahuasca (hoasca), inhibits monoamine oxidase-A and the cytochrome P450 isozyme 2D6, which metabolizes harmine. CYP 2D6 has genetic variations that may cause different effects among users. In 14 experienced male members of the União do Vegetal who received a standardized dose of hoasca, two subgroups of CYP 2D6 phenotypes—fast and slow metabolizers of harmine—were identified. In their religious practice, the presiding mestre individually adjusts the hoasca dose to compensate for metabolic differences and variations in alkaloid content.