The Grass Might Be Greener: Medical Marijuana Patients Exhibit Altered Brain Activity and Improved Executive Function after 3 Months of Treatment
Staci A Gruber, Kelly A. Sagar, M. Dahlgren, A. Gonenç, Rosemary T. Smith, Ashley M. Lambros, Korine B. Cabrera, S. Lukas
Frontiers in Pharmacology January 17, 2018 DOI: 10.3389/fphar.2017.00983 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Longitudinal study Peer reviewed |
|---|---|
| Population | Medical marijuana patients seeking treatment for various documented medical conditions |
| Intervention | Medical marijuana |
| Duration | 3-month treatment period |
| Topics | Cannabis |
| Key findings | After 3 months of MMJ treatment, patients demonstrated improved task performance and changes in brain activation patterns, with activation appearing more similar to healthy controls, along with improvements in clinical state and reduced prescription medication use. |
Abstract
The vast majority of states have enacted full or partial medical marijuana (MMJ) programs, causing the number of patients seeking certification for MMJ use to increase dramatically in recent years. Despite increased use of MMJ across the nation, no studies thus far have examined the specific impact of MMJ on cognitive function and related brain activation. In the present study, MMJ patients seeking treatment for a variety of documented medical conditions were assessed prior to initiating MMJ treatment and after 3 months of treatment as part of a larger longitudinal study. In order to examine the effect of MMJ treatment on task-related brain activation, MMJ patients completed the Multi-Source Interference Test (MSIT) while undergoing functional magnetic resonance imaging (fMRI). We also collected data regarding conventional medication use, clinical state, and health-related measures at each visit. Following 3 months of treatment, MMJ patients demonstrated improved task performance accompanied by changes in brain activation patterns within the cingulate cortex and frontal regions. Interestingly, after MMJ treatment, brain activation patterns appeared more similar to those exhibited by healthy controls from previous studies than at pre-treatment, suggestive of a potential normalization of brain function relative to baseline. These findings suggest that MMJ use may result in different effects relative to recreational marijuana (MJ) use, as recreational consumers have been shown to exhibit decrements in task performance accompanied by altered brain activation. Moreover, patients in the current study also reported improvements in clinical state and health-related measures as well as notable decreases in prescription medication use, particularly opioids and benzodiapezines after 3 months of treatment. Further research is needed to clarify the specific neurobiologic impact, clinical efficacy, and unique effects of MMJ for a range of indications and how it compares to recreational MJ use.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |
Citations in the library
Cited by 15
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- Coming off cannabis: a cognitive and magnetic resonance imaging study in patients with multiple sclerosis Brain July 3, 2019
- Cannabis Use and Neuroadaptation: A Call for Δ9-Tetrahydrocannabinol Challenge Studies Frontiers in Psychiatry April 14, 2022
- The effects of orally ingested Delta-9-Tetrahydrocannabinol on drivers' hazard perception and risk-taking behaviours: A within-subjects study of medicinal cannabis users. Psychopharmacology March 1, 2026
- Prolonged incubation with Δ9-tetrahydrocannabinol but not with cannabidiol induces synaptic alterations and mitochondrial impairment in immature and mature rat organotypic hippocampal slices. Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie February 1, 2025
and 10 more in the library
Cites 17
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- Cannabidiol in medical marijuana: Research vistas and potential opportunities. Pharmacological Research July 2017
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- Evidence for the Risks and Consequences of Adolescent Cannabis Exposure. Journal of the American Academy of Child & Adolescent Psychiatry March 2017
- Acute and Chronic Effects of Cannabinoids on Human Cognition-A Systematic Review. Biological Psychiatry April 1, 2016
and 12 more in the library