Neurophysiological and cognitive effects of smoked marijuana in frequent users.
Carl L. Hart, Aaron B Ilan, Alan Gevins, Erik W. Gunderson, Kemi Role, Jana Colley, Richard W Foltin
Pharmacology, Biochemistry, and Behavior September 2010 DOI: 10.1016/j.pbb.2010.06.003 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized controlled trial Peer reviewed |
|---|---|
| Sample size | 24 |
| Population | Daily marijuana smokers reporting approximately 24 marijuana cigarettes per week |
| Intervention | 1.8% |
| Dose | 0%, 1.8%, or 3.9% Δ9-THC w/w |
| Duration | Sessions separated by at least 72 hours |
| Measures | slow wave evoked potential amplitude, P300 amplitude, EEG power in the alpha band |
| Topics | Cannabis |
| Key findings | Marijuana did not significantly alter overall performance accuracy but increased response times and induced a response bias toward labeling new words as previously seen in the episodic memory task. It reduced slow wave evoked potential amplitude and decreased P300 amplitude and alpha band EEG power, while increasing heart rate and positive subjective effects in a THC concentration-dependent manner. |
Abstract
Previously, we reported that acute marijuana intoxication minimally affected complex cognitive performance of daily marijuana smokers. It is possible that the cognitive tests used were insensitive to marijuana-related cognitive effects. In the current study, electroencephalographic (EEG) signals were recorded as daily marijuana users performed additional tests of immediate working memory and delayed episodic memory, before and after smoking marijuana. Research volunteers (N=24), who reported smoking approximately 24 marijuana cigarettes/week, completed this study. Participants completed baseline computerized cognitive tasks, smoked a single marijuana cigarette (0%, 1.8%, or 3.9% (9)-THC w/w), and completed additional cognitive tasks; sessions were separated by at least 72-hours. Cardiovascular and subjective effects were also assessed throughout sessions. Overall performance accuracy was not significantly altered by marijuana, although the drug increased response times during task performance and induced a response bias towards labeling "new" words as having been previously seen in the verbal episodic memory task. Marijuana reduced slow wave evoked potential amplitude in the episodic memory task and decreased P300 amplitude and EEG power in the alpha band in the spatial working memory task. Heart rate and "positive" subjective-effect ratings were increased in a (9)-THC concentration-dependent manner. Relative to previous findings with infrequent marijuana users, the frequent users in the current study exhibited similar neurophysiological effects but more subtle performance effects. These data emphasize the importance of taking into account the drug-use histories of research participants and examining multiple measures when investigating marijuana-related effects on cognitive functioning.
Comparable studies
Other randomized controlled trials on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Healthy participants | 2012 | Randomized controlled trial | n = 48 |
| Distinct Effects of Δ9-Tetrahydrocannabinol and Cannabidiol on Neural Activation During Emotional Processing Healthy, English-native, right-handed men who had used cannabis 15 times or less in... | 2009 | Double-blind, randomized, placebo-controlled crossover trial | n = 15 |
| Acute Effects of a Single, Oral dose of d9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) Administration in Healthy Volunteers Healthy male subjects | 2012 | Randomized controlled trial | n = 16 |
| Modulation of Mediotemporal and Ventrostriatal Function in Humans by Δ9-Tetrahydrocannabinol Healthy, native English-speaking, right-handed men of white race/ethnicity who had used... | 2009 | Randomized controlled trial | n = 15 |
| Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition Healthy volunteers with a history of light cannabis use | 2019 | Randomized, double-blind, within-subjects crossover | n = 14 |
Citations in the library
Cited by 27
- Traditional marijuana, high‐potency cannabis and synthetic cannabinoids: increasing risk for psychosis World Psychiatry September 22, 2016
- Smoked Cannabis' Psychomotor and Neurocognitive Effects in Occasional and Frequent Smokers Journal of Analytical Toxicology March 4, 2015
- Acute memory and psychotomimetic effects of cannabis and tobacco both ‘joint’ and individually: a placebo-controlled trial Psychological Medicine May 30, 2017
- Acute effects of ayahuasca on neuropsychological performance: differences in executive function between experienced and occasional users Psychopharmacology June 20, 2013
- Cannabis and tolerance: acute drug impairment as a function of cannabis use history Scientific Reports May 26, 2016
and 22 more in the library
Cites 9
- Neurophysiological and subjective profile of marijuana with varying concentrations of cannabinoids Behavioural Pharmacology September 1, 2005
- Auditory mismatch negativity deficits in long-term heavy cannabis users. European Archives of Psychiatry and Clinical Neuroscience September 2010
- Sensory Gating Impairments in Heavy Cannabis Users are Associated with Altered Neural Oscillations Behavioral Neuroscience August 1, 2009
- Neurocognitive performance during acute THC intoxication in heavy and occasional cannabis users. Journal of Psychopharmacology May 2009
- Blunted psychotomimetic and amnestic effects of delta-9-tetrahydrocannabinol in frequent users of cannabis. Neuropsychopharmacology September 2008
and 4 more in the library