Classical hallucinogens and neuroimaging: A systematic review of human studies: Hallucinogens and neuroimaging.
Rafael G. Dos Santos, Flávia L. Osório, José Alexandre S. Crippa, Jaime E. C. Hallak
Neuroscience & Biobehavioral Reviews December 2016 DOI: 10.1016/j.neubiorev.2016.10.026 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Peer reviewed |
|---|---|
| Topics | Ayahuasca Default mode network DMT LSD Mescaline Psilocybin |
| Keywords | Hallucinogens Neuroimaging PET Spect FMRI |
| Key findings | The reviewed neuroimaging studies suggest that serotonergic hallucinogens acutely excite frontolateral/frontomedial, medial temporal, and occipital cortex while inhibiting the default mode network, and that long-term use is associated with posterior cingulate thinning, anterior cingulate thickening, and reduced neocortical 5-HT2A receptor binding. The authors propose these changes underlie increased introspection and positive mood, while cautioning about methodological heterogeneity and small samples. |
Abstract
Serotonergic hallucinogens produce alterations of perceptions, mood, and cognition, and have anxiolytic, antidepressant, and antiaddictive properties. These drugs act as agonists of frontocortical 5-HT2A receptors, but the neural basis of their effects are not well understood. Thus, we conducted a systematic review of neuroimaging studies analyzing the effects of serotonergic hallucinogens in man. Studies published in the PubMed, Lilacs, and SciELO databases until 12 April 2016 were included using the following keywords: "ayahuasca", "DMT", "psilocybin", "LSD", "mescaline" crossed one by one with the terms "mri", "fmri", "pet", "spect", "imaging" and "neuroimaging". Of 279 studies identified, 25 were included. Acute effects included excitation of frontolateral/frontomedial cortex, medial temporal lobe, and occipital cortex, and inhibition of the default mode network. Long-term use was associated with thinning of the posterior cingulate cortex, thickening of the anterior cingulate cortex, and decreased neocortical 5-HT2A receptor binding. Despite the high methodological heterogeneity and the small sample sizes, the results suggest that hallucinogens increase introspection and positive mood by modulating brain activity in the fronto-temporo-parieto-occipital cortex.
Comparable studies
Other systematic reviews and meta-analyses on mescaline, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Risk assessment of ritual use of oral dimethyltryptamine (DMT) and harmala alkaloids Humans (ritual ayahuasca use) | 2006 | Systematic review | |
| Drug–drug interactions involving classic psychedelics: A systematic review | 2023 | Systematic review | |
| Psychedelic‐assisted treatment for substance use disorder: A narrative systematic review Participants in studies of psychedelic-assisted treatment for alcohol, tobacco, and... | 2025 | Systematic review | n = 2,035 |
| The immunomodulatory effects of classical psychedelics: A systematic review of preclinical studies Preclinical animal and in vitro studies | 2024 | Systematic review | |
| Drug-drug interactions between classic psychedelics and psychoactive drugs: a systematic review Humans | 2023 | Systematic review |
Citations in the library
Cited by 85
- Psychedelics, Meditation, and Self-Consciousness Frontiers in Psychology September 4, 2018
- Self unbound: ego dissolution in psychedelic experience Neuroscience of Consciousness 2017
- Classical psychedelics for the treatment of depression and anxiety: A systematic review. Journal of Affective Disorders November 1, 2019
- Long-term effects of psychedelic drugs: A systematic review Neuroscience & Biobehavioral Reviews March 16, 2020
- Efficacy, tolerability, and safety of serotonergic psychedelics for the management of mood, anxiety, and substance-use disorders: a systematic review of systematic reviews Expert Review of Clinical Pharmacology August 13, 2018
and 80 more in the library
Cites 83
- Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance Psychopharmacology July 7, 2006
- The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs Frontiers in Human Neuroscience 2014
- Pilot Study of Psilocybin Treatment for Anxiety in Patients With Advanced-Stage Cancer Archives of General Psychiatry September 7, 2010
- Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin Proceedings of the National Academy of Sciences January 23, 2012
- Psilocybin-assisted treatment for alcohol dependence: A proof-of-concept study Journal of Psychopharmacology January 13, 2015
and 78 more in the library