The dose-dependent psychomotor effects of intravenous delta-9-tetrahydrocannabinol (Δ9-THC) in humans.
Douglas L Boggs, Jose A Cortes-Briones, Toral Surti, Christina Luddy, Mohini Ranganathan, John D Cahill, Andrew R Sewell, Deepak C D'Souza, Patrick D. Skosnik
Journal of Psychopharmacology December 2018 DOI: 10.1177/0269881118799953 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Randomized, double-blind, within-subject, cross-over, counterbalanced study Peer reviewed |
|---|---|
| Sample size | 23 |
| Population | Former cannabis users abstinent for a minimum of three months |
| Intervention | delta-9-tetrahydrocannabinol |
| Dose | placebo, 0.015 mg/kg, and 0.03 mg/kg |
| Measures | Cambridge Neuropsychological Test Automated Battery Motor Screening Task, Lafayette Instrument Grooved Pegboard task, Paced Finger-Tapping Task, Cambridge Neuropsychological Test Automated Battery Rapid Visual Processing Task |
| Topics | Cannabis |
| Keywords | Psychomotor |
| Key points | Intravenous delta-9-tetrahydrocannabinol caused dose-dependent impairments in fine motor control and motor timing, but not gross motor performance or sustained attention. Despite greater motor impairment and higher blood delta-9-tetrahydrocannabinol at the higher dose, participants reported similar levels of intoxication across the two active drug conditions, suggesting subjective feelings of intoxication are dissociable from cannabinoid-induced psychomotor effects. |
Abstract
Binding studies have demonstrated that levels of the cannabinoid receptor type-1 are highest in the basal ganglia and cerebellum, two areas critical for motor control. However, no studies have systematically examined the dose-related effects of intravenous delta-9-tetrahydrocannabinol, the primary cannabinoid receptor type-1 partial agonist in cannabis, on broad domains of psychomotor function in humans. Therefore, three domains of psychomotor function were assessed in former cannabis users (cannabis abstinent for a minimum of three months; n=23) in a three test-day, within-subject, double-blind, randomized, cross-over, and counterbalanced study during which they received intravenous delta-9-tetrahydrocannabinol (placebo, 0.015 mg/kg, and 0.03 mg/kg). Gross motor function was assessed via the Cambridge Neuropsychological Test Automated Battery Motor Screening Task, fine motor control via the Lafayette Instrument Grooved Pegboard task, and motor timing via a Paced Finger-Tapping Task. In addition, the Cambridge Neuropsychological Test Automated Battery Rapid Visual Processing Task was utilized to determine whether delta-9-tetrahydrocannabinol-induced motor deficits were confounded by disruptions in sustained attention. Delta-9-tetrahydrocannabinol resulted in robust dose-dependent deficits in fine motor control (Grooved Pegboard Task) and motor timing (Paced Finger-Tapping Task), while gross motor performance (Motor Screening Task) and sustained attention (Rapid Visual Processing Task) were unimpaired. Interestingly, despite the observed dose-dependent increases in motor impairment and blood levels of delta-9-tetrahydrocannabinol, subjects reported similar levels of intoxication in the two drug conditions. These data suggest that while several domains of motor function are disrupted by delta-9-tetrahydrocannabinol, subjective feelings of intoxication are dissociable from cannabinoid-induced psychomotor effects. Results are discussed in terms of the potential neural mechanisms of delta-9-tetrahydrocannabinol in motor structures.
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 6
- Understanding cannabis use and car crashes: Insights from a randomized trial using a driving simulator on THC blood levels and subjective measures of sleepiness and performance. Journal of safety research December 1, 2025
- Clinical, Cognitive, and Neurobiological Correlates of Impaired Timing Abilities Associate to Cannabis Use: a Systematic Review International Journal of Mental Health and Addiction August 29, 2023
- Sex differences in the acute effects of intravenous (IV) delta-9 tetrahydrocannabinol (THC). Psychopharmacology May 2022
- Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: a systematic meta-review of meta-analyses. Addiction January 19, 2022
- The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review Frontiers in Psychiatry February 16, 2021
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- Sex differences in the subjective effects of oral Δ9-THC in cannabis users. Pharmacology, Biochemistry, and Behavior January 2017
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- Separate and combined effects of the GABAA positive allosteric modulator diazepam and Δ⁹-THC in humans discriminating Δ⁹-THC. Drug and Alcohol Dependence October 1, 2014
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