Medial temporal structures and memory functions in adolescents with heavy cannabis use
M. Ashtari, B. Avants, L. Cyckowski, K. Cervellione, D. Roofeh, Philip A Cook, J. Gee, S. Sevy, S. Kumra
Journal of Psychiatric Research February 5, 2011 DOI: 10.1016/j.jpsychires.2011.01.004 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case-control study Peer reviewed |
|---|---|
| Sample size | 28 |
| Population | Treatment-seeking adolescents aged 18-20 with prior heavy cannabis use and demographically matched normal controls |
| Duration | Average of 6.7 months of drug abstinence prior to assessment |
| Measures | California Verbal Learning Test (CVLT) |
| Topics | Cannabis |
| Key findings | Heavy-cannabis users showed significantly smaller right and left hippocampal volumes than controls, with no significant amygdala difference, and the normal correlation between hippocampal volume and verbal learning and memory was absent in users. The authors argue these findings support a hypothesis that heavy cannabis use may adversely affect hippocampal development, while noting the alternative that smaller hippocampi may be a pre-existing risk factor for cannabis dependence. |
Abstract
Converging lines of evidence suggest an adverse effect of heavy cannabis use on adolescent brain development, particularly on the hippocampus. In this preliminary study, we compared hippocampal morphology in 14 “treatment-seeking” adolescents (aged 18-20) with a history of prior heavy-cannabis use (5.8 joints/day) after an average of 6.7 months of drug abstinence, and 14 demographically matched normal controls. Participants underwent a high-resolution 3D MRI as well as cognitive testing including the California Verbal Learning Test (CVLT). Heavy-cannabis users showed significantly smaller volumes of the right (p< .04) and left (p< .02) hippocampus, but no significant differences in the amygdala region compared to controls. In controls, larger hippocampus volumes were observed to be significantly correlated with higher CVLT verbal learning and memory scores, but these relationships were not observed in cannabis users. In cannabis users, a smaller right hippocampus volume was correlated with a higher amount of cannabis use (r= - .57, p< .03). These data support a hypothesis that heavy-cannabis use may have an adverse effect on hippocampus development. These findings, after an average 6.7 month of supervised abstinence, lend support to a theory that cannabis use may impart long-term structural and functional damage. Alternatively, the observed hippocampal volumetric abnormalities may represent a risk factor for cannabis dependence. These data have potential significance for understanding the observed relationship between early cannabis exposure during adolescence and subsequent development of adult psychopathology reported in the literature for schizophrenia and related psychotic disorders.
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 31
- The neuropsychopharmacology of cannabis: A review of human imaging studies Pharmacology & Therapeutics October 20, 2018
- Cannabis Use during Adolescent Development: Susceptibility to Psychiatric Illness Frontiers in Psychiatry 2013
- Long-term consequences of adolescent cannabinoid exposure in adult psychopathology Frontiers in Neuroscience November 10, 2014
- Grey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in Adolescence Journal of Neuroscience January 14, 2019
- Cannabis‐related deficits in real‐world memory Human Psychopharmacology: Clinical and Experimental March 1, 2012
and 26 more in the library
Cites 8
- The influence of recency of use on fMRI response during spatial working memory in adolescent marijuana users. Journal of Psychoactive Drugs September 2010
- Chronic use of cannabis and poor neural efficiency in verbal memory ability. Psychopharmacology May 2010
- Cannabis use and memory brain function in adolescent boys: a cross-sectional multicenter functional magnetic resonance imaging study. Journal of the American Academy of Child and Adolescent Psychiatry April 14, 2010
- Changes in hippocampal morphology and neuroplasticity induced by adolescent THC treatment are associated with cognitive impairment in adulthood. Hippocampus August 2009
- Abstinent adolescent marijuana users show altered fMRI response during spatial working memory. Psychiatry Research May 30, 2008
and 3 more in the library