OPEN Foundation

V. Frokjaer

Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers

Abstract

BACKGROUND:

Recent studies have suggested therapeutic benefits of psychedelics for a variety of mental health conditions. The understanding of how single psychedelic administrations can induce long-lasting effects are, in large, still lacking. However, recent studies in both healthy and clinical populations suggest a role for personality changes.

AIM:

To test support for some of these plausible mechanisms we evaluated (cross-sectional) associations between recreational use of psychedelics and 3,4-methylene-dioxymethamphetamine (MDMA) and (a) personality measures and (b) key markers of cerebral serotonergic signalling (serotonin transporter and serotonin-2A-receptor binding).

METHODS:

In 10 psychedelic-preferring recreational users, 14 MDMA-preferring users and 21 non-using controls, personality was assessed using the ‘big five’ instrument Revised NEO Personality Inventory (NEO-PI-R). Frontal serotonin transporter and serotonin-2A-receptor binding potentials were quantified using [11C]DASB and [18F]altanserin positron emission tomography, respectively.

RESULTS:

Of the five NEO-PI-R traits, only openness to experience scores differed between the three groups; psychedelic-preferring recreational users showing higher openness to experience scores when compared with both MDMA-preferring users and controls. Openness to experience scores were positively associated with lifetime number of psychedelic exposures, and among all MDMA-preferring user/psychedelic-preferring recreational user individuals, frontal serotonin transporter binding – but not frontal serotonin-2A-receptor binding – was positively associated with openness to experience.

CONCLUSION:

Our findings from this cross-sectional study support increasing evidence of a positive association between psychedelic experiences and openness to experience, and (a) expands this to the context of ‘recreational’ psychedelics use, and (b) links serotonergic neurotransmission to openness to experience. A modulation of personality induced by psychedelic experiences may have important therapeutic implications via its impact on peoples’ value systems, cognitive flexibility, and individual and social behaviour.

Erritzoe, D., Smith, J., Fisher, P. M., Carhart-Harris, R., Frokjaer, V. G., & Knudsen, G. M. (2019). Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers. Journal of Psychopharmacology., 10.1177/0269881119827891
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Trait Openness and serotonin 2A receptors in healthy volunteers: A positron emission tomography study.

Abstract

Recent research found lasting increases in personality trait Openness in healthy individuals and patients after administration of the serotonin 2A receptor (5-HT2A R) agonist psilocybin. However, no studies have investigated whether 5-HT2A R availability as imaged using positron emission tomography (PET) is associated with this trait. In 159 healthy individuals (53 females), the association between 5-HT2A R binding in neocortex imaged with [18 F]altanserin or [11 C]Cimbi-36 PET and personality trait Openness was investigated using linear regression models. In these models the influence of sex on the association was also investigated. Trait Openness was assessed with the NEO Personality Inventory-Revised. No significant associations between neocortical 5-HT2A R binding and trait Openness were found for [18F]altanserin (p = 0.5) or [11 C]Cimbi-36 (p = 0.8). Pooling the data in a combined model did not substantially change our results (p = 0.4). No significant interactions with sex were found (p > 0.35). Our results indicate that differences in 5-HT2A R availability are not related to variations in trait Openness in healthy individuals. Although stimulation of the 5-HT2A R with compounds such as psilocybin may contribute to long-term changes in trait Openness, there is no evidence in favor of an association between 5-HT2A R and trait Openness.
Stenbæk, D. S., Kristiansen, S., Burmester, D., Madsen, M. K., Frokjaer, V. G., Knudsen, G. M., & Fisher, P. M. (2019). Trait Openness and serotonin 2A receptors in healthy volunteers: A positron emission tomography study. Human brain mapping., 10.1002/hbm.24511
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In Vivo Imaging of Cerebral Serotonin Transporter and Serotonin 2A Receptor Binding in MDMA and Hallucinogen Users

Abstract

Context:
Both hallucinogens and 3,4-methylenedioxy-methamphetamine (MDMA or “ecstasy”) have direct agonistic effects on postsynaptic serotonin 2A receptors, the key site for hallucinogenic actions. In addition, MDMA is a potent releaser and reuptake inhibitor of presynaptic serotonin.

Objective:
To assess the differential effects of MDMA and hallucinogen use on cerebral serotonin transporter (SERT) and serotonin2Areceptor binding.

Design:
A positron emission tomography study of 24 young adult drug users and 21 nonusing control partici-pants performed with carbon 11 (11C)–labeled 3-amino-4-[2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzo-nitrile (DASB) and fluorine 18 (18F)–labeled altanserin, respectively. Scans were performed in the user group after a minimum drug abstinence period of 11 days, and the group was subdivided into hallucinogen-preferring users (n = 10) and MDMA-preferring users (n = 14).

Participants:
Twenty-four young adult users of MDMA and/or hallucinogenic drugs and 21 nonusing controls.

Main Outcome Measures:
In vivo cerebral SERT and serotonin 2A receptor binding.

Results:
Compared with nonusers, MDMA-preferring users showed significant decreases in SERT nondisplaceable binding potential (neocortex, −56%; pallidostriatum, −19%; and amygdala, −32%); no significant changes were seen in hallucinogen-preferring users. Both cortical and pallidostriatal SERT nondisplaceable binding potential was negatively correlated with the number of life-time MDMA exposures, and the time of abstinence from MDMA was positively correlated with subcortical, but not cortical, SERT binding. A small decrease in neocortical serotonin 2A receptor binding in the serotonin 2A receptor agonist users (both user groups) was also detected.

Conclusions
We found evidence that MDMA but not hallucinogen use is associated with changes in the cerebral presynaptic serotonergic transmitter system. Because hallucinogenic drugs primarily have serotonin 2A receptor agonistic actions, we conclude that the negative association between MDMA use and cerebral SERT binding is mediated through a direct presynaptic MDMA effect rather than by the serotonin 2A agonistic effects of MDMA. Our cross-sectional data suggest that subcortical, but not cortical, recovery of SERT binding might take place after several months of MDMA abstinence.

Erritzoe, D., Frokjaer, V. G., Holst, K. K., Christoffersen, M., Johansen, S. S., Svarer, C., … Knudsen, G. M. (2011). In Vivo Imaging of Cerebral Serotonin Transporter and Serotonin 2A Receptor Binding in 3,4-Methylenedioxymethamphetamine (MDMA or “Ecstasy”) and Hallucinogen Users. Archives of General Psychiatry, 68(6), 562-576. http://dx.doi.org/10.1001/archgenpsychiatry.2011.56
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