Impact of psilocybin on cognitive function: A systematic review

Psychiatry and Clinical Neurosciences, vol. 78, pp. 744–764

Abstract

Psilocybin is a classic psychedelic with demonstrated preliminary clinical efficacy in a range of psychiatric disorders. Evaluating the impact of psilocybin on cognitive function is essential to unravel its potential benefits and risks. In this systematic review, we assessed psilocybin's effect on cognitive function through a comprehensive search of electronic databases from inception to January 2024, identifying 20 articles involving 2,959 participants. While 85% of studies were conducted in healthy volunteers, most of these studies (85%) used macrodoses, ranging from 45 μg/kg to 30 mg/70 kg. Various cognitive aspects were evaluated and yielded mixed results. Global cognitive function, and processing speed remained mostly unchanged in healthy individuals; However, a limited number of studies reported improvements in certain areas such as sustained attention, working memory, and executive function especially in patients with treatment-resistant depression (TRD). Emotional processing was positively modified, particularly in TRD patients. Psilocybin was observed to enhance emotional empathy without significantly altering cognitive empathy and social cognition. Cognitive flexibility and creative cognition were noted to initially decline but could potentially improve over time. Additionally, with respect to learning and memory skills, psilocybin showed promise in improving specific memory types such as semantic associations and associative learning, while its effects on episodic and verbal memory have been less pronounced compared to other cognitive enhancers. The observed mixed findings underscore the complexity of psilocybin's cognitive influence. Further research is essential to provide a clearer understanding of psilocybin's impact on cognitive domains and to guide the development of safe and effective interventions.

Authors 14

1. Shakila Meshkat

   St. Michael's Hospital · Unity Health Toronto

   Affiliation as printed

   Interventional Psychiatry Program St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada

2. Triana Juliana Tello-Gerez

   St. Michael's Hospital · Unity Health Toronto

   Affiliation as printed

   Interventional Psychiatry Program St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada

3. Fatemeh Gholaminezhad

   St. Michael's Hospital · Unity Health Toronto

   Affiliation as printed

   Interventional Psychiatry Program St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada

4. Benjamin Thomas Dunkley

   University of Toronto · Hospital for Sick Children

   Affiliation as printed

   Institute of Medical Science, University of Toronto Toronto Ontario Canada

   Neurosciences and Mental Health Hospital for Sick Children Research Institute Toronto Ontario Canada

5. Amy Claire Reichelt

   Western University · The University of Adelaide

   Affiliation as printed

   Department of Physiology and Pharmacology Western University London Ontario Canada

   School of Biomedicine, Adelaide Medical School, University of Adelaide Adelaide South Australia Australia

6. David Erritzøe

   Imperial College London

   Affiliation as printed

   Centre for Psychedelic Research, Department of Brain Sciences Imperial College London London UK

7. Eric H. G. J. M. Vermetten Aachen Department of Psychiatry Leiden University Medical Center Leiden Netherlands

   Leiden University Medical Center

   Affiliation as printed

   Department of Psychiatry Leiden University Medical Center Leiden Netherlands

8. Yanbo Zhang

   University of Alberta

   Affiliation as printed

   Department of Psychiatry University of Alberta Edmonton Alberta Canada

9. Andrew James Greenshaw

   University of Alberta

   Affiliation as printed

   Department of Psychiatry University of Alberta Edmonton Alberta Canada

10. Lisa Burback

    University of Alberta · Neuroscience and Mental Health Institute

    Affiliation as printed

    Department of Psychiatry University of Alberta Edmonton Alberta Canada

    Neuroscience and Mental Health Institute (NMHI), University of Alberta Edmonton Alberta Canada

11. Olga Winkler

    University of Alberta · Neuroscience and Mental Health Institute

    Affiliation as printed

    Department of Psychiatry University of Alberta Edmonton Alberta Canada

    Neuroscience and Mental Health Institute (NMHI), University of Alberta Edmonton Alberta Canada

12. Rakesh Jetly

    University of Ottawa · Royal Ottawa Mental Health Centre · Institute of Mental Health Research

    Affiliation as printed

    The Institute of Mental Health Research, University of Ottawa, Royal Ottawa Hospital Ottawa Ontario Canada

13. Leah M. Mayo

    University of Calgary · Hotchkiss Brain Institute · Mathison Centre for Mental Health Research and Education

    Affiliation as printed

    Department of Psychiatry Mathison Centre for Mental Health Research and Education, Hotchkiss Brain Institute, University of Calgary Calgary Alberta Canada

14. Venkat Bhat corresponding

    St. Michael's Hospital · University of Toronto · Unity Health Toronto

    Affiliation as printed

    Department of Psychiatry University of Toronto Toronto Ontario Canada

    Interventional Psychiatry Program St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada

    Neuroscience Research Program St. Michael's Hospital, Unity Health Toronto Toronto Ontario Canada