Grey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in Adolescence
Catherine Orr, Philip A. Spechler, Zhipeng Cao, Matthew D. Albaugh, Bader Chaarani, Scott Mackey, Deepak Cyril D’souza, Nicholas A. Allgaier, Tobias Banaschewski, Arun L.w. Bokde, Uli Bromberg, Christian Büchel, Erin Burke Quinlan, Patricia Conrod, Sylvane Desrivières, Herta Flor, Vincent Frouin, Penny Anne Gowland, Andreas Heinz, Bernd Ittermann, Jean-Luc Martinot, Marie-Laure Paillère Martinot, Frauke Nees, Dimitri Papadopoulos Orfanos, Tomáš Paus, Luise Poustka, Sabina Millenet, Juliane Hilde Fröhner, Rajiv Radhakrishnan, Michael N. Smolka, Henrik Walter, Robert Whelan, Günter Schumann, Alexandra S. Potter, Hugh P Garavan
Journal of Neuroscience January 14, 2019 DOI: 10.1523/jneurosci.3375-17.2018 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational case-control study with longitudinal follow-up Peer reviewed |
|---|---|
| Sample size | 46 |
| Population | 14-year-old adolescents (males and females) with one or two instances of cannabis use and matched THC-naive controls |
| Measures | Perceptual Reasoning Index |
| Topics | Cannabis |
| Citations | 100 |
| Key findings | Adolescents who had used cannabis just once or twice showed greater gray matter volume in bilateral medial temporal lobes, posterior cingulate, lingual gyri, and cerebellum compared with non-users. Longitudinal data suggested these differences were unlikely to precede cannabis use. In users, temporal-lobe volume was associated with Perceptual Reasoning Index performance and later generalized anxiety symptoms, with the authors proposing a role for the endocannabinoid system. |
Abstract
Rates of cannabis use among adolescents are high, and are increasing concurrent with changes in the legal status of marijuana and societal attitudes regarding its use. Recreational cannabis use is understudied, especially in the adolescent period when neural maturation may make users particularly vulnerable to the effects of Δ-9-tetrahydrocannabinol (THC) on brain structure. In the current study, we used voxel-based morphometry to compare gray matter volume (GMV) in forty-six 14-year-old human adolescents (males and females) with just one or two instances of cannabis use and carefully matched THC-naive controls. We identified extensive regions in the bilateral medial temporal lobes as well as the bilateral posterior cingulate, lingual gyri, and cerebellum that showed greater GMV in the cannabis users. Analysis of longitudinal data confirmed that GMV differences were unlikely to precede cannabis use. GMV in the temporal regions was associated with contemporaneous performance on the Perceptual Reasoning Index and with future generalized anxiety symptoms in the cannabis users. The distribution of GMV effects mapped onto biomarkers of the endogenous cannabinoid system providing insight into possible mechanisms for these effects. SIGNIFICANCE STATEMENTAlmost 35% of American 10th graders have reported using cannabis and existing research suggests that initiation of cannabis use in adolescence is associated with long-term neurocognitive effects. We understand very little about the earliest effects of cannabis use, however, because most research is conducted in adults with a heavy pattern of lifetime use. This study presents evidence suggesting structural brain and cognitive effects of just one or two instances of cannabis use in adolescence. Converging evidence suggests a role for the endocannabinoid system in these effects. This research is particularly timely as the legal status of cannabis is changing in many jurisdictions and the perceived risk by youth associated with smoking cannabis has declined in recent years.
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 |