The legalization of recreational and medical marijuana in several states has brought about more urgent questions about the potential cognitive and neuropsychiatric effects of cannabis use, particularly related to long-term use. Today we talk with Igor Grant, M.D., F.R.C.P., about contemporary cannabis research and how neuropsychologists should consider cannabis use when completing neuropsychological assessments.
A pdf of the transcript for this episode is available here.
Topics Covered
Cannabis and Cognition
- List the physiological effects of cannabis on cannabis users during or after use
- Review the mechanisms of recreational cannabis use and its effect on cognition
- Discuss the relationship between psychosis and cannabis use
- Consider the risks of cannabis use in adolescence
- Describe evidence for and against long-term effects of cannabis use
- List factors to consider when completing a neuropsychological assessment of a cannabis user
- Review results of neuroimaging studies of cannabis users
- Describe factors that could change the impact of cannabis on cognition
- Discuss driving safety while under the influence of cannabis
- Compare the cognitive, behavioral, and motor effects of cannabis at different THC levels
- Compare the mechanisms of action and effects of THC and CBD
- Review available research involving pain and cannabis use
- Discuss cannabis scheduling as a Schedule 1 drug
- Examine contemporary research involving cancer and THC use
Dr. Grant’s Career
- Discuss how Dr. Grant became involved in neuropsychology research as a psychiatrist
- Review Dr. Grant’s involvement in the International Neuropsychological Society and the founding of the Journal of the International Neuropsychological Society
About Igor
Igor Grant, M.D., F.R.C.P (C), is a Distinguished Professor of the Department of Psychiatry at the University of California, San Diego School of Medicine. He is Director of the HIV Neurobehavioral Research Program (HNRP), which includes the California NeuroAIDS Tissue Network (CNTN), the Translational Methamphetamine AIDS Research Center (TMARC), the HIV Neurobehavioral Research Center (HNRC), the CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER), and the University of California Center for Medicinal Cannabis Research (CMCR). Dr. Grant is the founding Editor of the Journal of the International Neuropsychological Society and founding co-editor of the journal AIDS and Behavior.
Selected References
Colizzi, M., & Bhattacharyya, S. (2017). Does cannabis composition matter? Differential effects of delta-9-tetrahydrocannabinol and cannabidiol on human cognition. Current Addiction Reports, 4(2), 62-74.
Curran, H. V., Freeman, T. P., Mokrysz, C., Lewis, D. A., Morgan, C. J., & Parsons, L. H. (2016). Keep off the grass? Cannabis, cognition and addiction. Nature Reviews Neuroscience, 17(5), 293-306.
Grant, I., Atkinson, J. H., Gouaux, B., & Wilsey, B. (2012). Medical marijuana: clearing away the smoke. The open neurology journal, 6, 18.
Gruber, S. A., Sagar, K. A., Dahlgren, M. K., Gonenc, A., Smith, R. T., Lambros, A. M., Cabrera, K.B., & Lukas, S. E. (2018). The grass might be greener: medical marijuana patients exhibit altered brain activity and improved executive function after 3 months of treatment. Frontiers in pharmacology, 8, 983.
Gobbi, G., Atkin, T., Zytynski, T., Wang, S., Askari, S., Boruff, J., Ware, M., Marmorstein, N., Cipriani, A., Dendukuri, N., & Mayo, N. (2019). Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood: a systematic review and meta-analysis. JAMA psychiatry, 76(4), 426-434.
Hanson, K. L., Winward, J. L., Schweinsburg, A. D., Medina, K. L., Brown, S. A., & Tapert, S. F. (2010). Longitudinal study of cognition among adolescent marijuana users over three weeks of abstinence. Addictive behaviors, 35(11), 970-976.
Humphreys, K., & Saitz, R. (2019). Should physicians recommend replacing opioids with cannabis?. Jama, 321(7), 639-640.
Liang, D., Bao, Y., Wallace, M., Grant, I., & Shi, Y. (2018). Medical cannabis legalization and opioid prescriptions: evidence on US Medicaid enrollees during 1993–2014. Addiction, 113(11), 2060-2070.
Lochte, B. C., Beletsky, A., Samuel, N. K., & Grant, I. (2017). The use of cannabis for headache disorders. Cannabis and Cannabinoid Research, 2(1), 61-71.
Piomelli, D., Cooper, Z., Abrams, D., Grant, I., & Patel, S. (2017). A guide to the national academy of science report on cannabis: an exclusive discussion with panel members. Cannabis and Cannabinoid Research, 2(1), 155-159.
Sagar, K. A., & Gruber, S. A. (2018). Marijuana matters: reviewing the impact of marijuana on cognition, brain structure and function, & exploring policy implications and barriers to research. International Review of Psychiatry, 30(3), 251-267.
Solowij, N., & Pesa, N. (2012). Cannabis and cognition: short and long-term effects. Marijuana and madness, 2, 91-102.
Tyree, G. A., Sarkar, R., Bellows, B. K., Ellis, R. J., Atkinson, J. H., Marcotte, T. D., Wallace, M.W., Grant, I., Shi, Y., Murphy, J.D. & Grelotti, D. J. (2019). A Cost-Effectiveness Model for Adjunctive Smoked Cannabis in the Treatment of Chronic Neuropathic Pain. Cannabis and cannabinoid research, 4(1), 62-72.
Volkow, N. D., Swanson, J. M., Evins, A. E., DeLisi, L. E., Meier, M. H., Gonzalez, R., Bloomfield, M.A., Curran, H.V., & Baler, R. (2016). Effects of cannabis use on human behavior, including cognition, motivation, and psychosis: a review. JAMA psychiatry, 73(3), 292-297.
Wilsey, B., Atkinson, J. H., Marcotte, T. D., & Grant, I. (2015). The medicinal cannabis treatment agreement: Providing information to chronic pain patients via a written document. The Clinical journal of pain, 31(12), 1087.
