Altered brain tissue composition in heavy marijuana users.
John A Matochik, Dana A Eldreth, Jean Lud Cadet, Karen I Bolla
Drug and Alcohol Dependence January 7, 2005 DOI: 10.1016/j.drugalcdep.2004.06.011 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case-control neuroimaging study Peer reviewed |
|---|---|
| Sample size | 19 |
| Population | 11 heavy marijuana users and 8 non-users, all male |
| Topics | Cannabis |
| Key findings | Heavy marijuana users showed lower gray matter density in the right parahippocampal gyrus and greater density near the precentral gyrus bilaterally and the right thalamus, plus lower white matter density in the left parietal lobe and higher density around the left parahippocampal and fusiform gyri. Longer duration of use correlated with higher white matter density in the left precentral gyrus. The authors suggest these preliminary findings indicate possible structural brain differences warranting further investigation. |
Abstract
Marijuana is the most widely used illicit substance in the United States; however, previous imaging studies have not detected altered brain structure in marijuana users compared to non-users. Voxel-based morphometry was used to investigate possible differences in brain tissue composition in a group of 11 heavy marijuana users and a group of 8 non-users. All participants were male. Statistical comparisons were made at the voxel level on T1-weighted magnetic resonance images to determine differences in gray matter and white matter tissue density. Compared to non-users, marijuana users had lower gray matter density in a cluster of voxels in the right parahippocampal gyrus (P = 0.0001), and greater density bilaterally near the precentral gyrus and the right thalamus (P < 0.04). Marijuana users also had lower white matter density in the left parietal lobe (P = 0.03), and higher density around the parahippocampal and fusiform gyri on the left side compared to non-users (P < 0.002). Longer duration of marijuana use (in years) was significantly correlated with higher white matter tissue density in the left precentral gyrus (P = 0.045). Our preliminary results suggest evidence of possible structural differences in the brain of heavy marijuana users, and localize regions for further investigation of the effects of marijuana in the brain.
Comparable studies
Other experimental studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Smoked Cannabis' Psychomotor and Neurocognitive Effects in Occasional and Frequent Smokers Occasional (<2x/week) and frequent (≥4x/week) cannabis smokers | 2015 | Controlled within-subjects study | n = 25 |
| Dissociable effects of cannabis with and without cannabidiol on the human brain’s resting-state functional connectivity Healthy volunteers experienced with cannabis but not regular users | 2019 | Within-subjects experimental design | n = 17 |
| Which biological and self-report measures of cannabis use predict cannabis dependency and acute psychotic-like effects? Young cannabis users | 2018 | Observational study (naturalistic, within-subject counterbalanced design) | n = 410 |
| Cannabis Essential Oil: A Preliminary Study for the Evaluation of the Brain Effects Healthy volunteers | 2018 | Experimental study | n = 5 |
| Coming off cannabis: a cognitive and magnetic resonance imaging study in patients with multiple sclerosis Patients with multiple sclerosis who began using cannabis after disease onset, used it... | 2019 | Quasi-experimental study with odd-even allocation | n = 40 |
Citations in the library
Cited by 44
- The neuropsychopharmacology of cannabis: A review of human imaging studies Pharmacology & Therapeutics October 20, 2018
- Neuroimaging in cannabis use: a systematic review of the literature Psychological Medicine July 23, 2009
- Effects of Cannabis on Impulsivity: A Systematic Review of Neuroimaging Findings Current Pharmaceutical Design May 10, 2014
- The effect of cannabis on the brain: can it cause brain anomalies that lead to increased risk for schizophrenia? Current Opinion in Psychiatry March 1, 2008
- Impact of cannabis use on brain metabolism using 31P and 1H magnetic resonance spectroscopy Neuroradiology September 22, 2023
and 39 more in the library