Elucidating the acute effects of medically prescribed oral and vaporised delta-9-tetrahydrocannabinol on cognitive functions important for driving.
Kayla B Stefanidis, Carla Schiemer, Taren Mieran, Andrew Hill, Mark S Horswill, Mathew J Summers
Drug and Alcohol Review May 2025 DOI: 10.1111/dar.14060 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Within-subject experimental study with counterbalanced baseline and post-cannabis sessions Peer reviewed |
|---|---|
| Sample size | 78 |
| Population | Medicinal cannabis patients: 41 oral cannabis oil users (Study 1) and 37 cannabis flower users (Study 2) |
| Dose | one dose |
| Duration | Baseline and post-cannabis sessions approximately 1 week apart; cognitive battery 90 min after oral oil or 15 min after vaporised flower |
| Measures | Trail Making Test Part B (TMT B), TMT ratio |
| Topics | Cannabis |
| Keywords | Cognition Delta‐9‐tetrahydrocannabinol Neuropsychology |
| Key findings | Acute cannabis oil or flower use did not change information processing speed, divided or sustained attention, or inhibitory control in medicinal cannabis patients after excluding those with a positive drug indication at session start, which the authors say highlights tolerance. However, TMT B performance dropped significantly, and the TMT ratio fell after cannabis oil, suggesting TMT B may be sensitive to acute cannabis use. |
Abstract
This program of research investigated the acute effects of orally ingested (Study 1) and vaporised (Study 2) cannabis containing delta-9-tetrahydrocannabinol (THC) on cognitive functions relevant for driving in two samples of medicinal cannabis patients (Study 1 N = 41 oral users; Study 2 N = 37 flower users). Participants completed counterbalanced baseline (no cannabis) and cannabis consumption (post-cannabis) appointments scheduled approximately 1 week apart. During each session, participants were administered a cognitive battery assessing information processing speed, sustained and divided attention, inhibitory control and mental flexibility. In the post-cannabis condition, the battery was completed 90 min after consuming one dose of cannabis oil (Study 1) or 15 min after vaporising one dose of cannabis flower (Study 2). In both samples, acute cannabis oil and flower administration did not induce a change in information processing speed, divided and sustained attention, or inhibitory control performance (after excluding participants with a positive drug indication at the start of either session), highlighting the moderating role of tolerance. However, significant reductions in TMT B performance were observed. Further, TMT ratio was significantly reduced post consumption of cannabis oil. TMT B may be sensitive to acute cannabis consumption in medicinal cannabis patients. However, further research is needed to determine the nature and duration of these effects, and whether such effects vary depending on the population studied (e.g., regular vs. new users).
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
Cites 5
- Neurophysiological functioning of occasional and heavy cannabis users during THC intoxication Psychopharmacology October 5, 2011
- The why behind the high: determinants of neurocognition during acute cannabis exposure. Nature Reviews Neuroscience July 1, 2021
- Determining the magnitude and duration of acute Δ9-tetrahydrocannabinol (Δ9-THC)-induced driving and cognitive impairment: A systematic and meta-analytic review. Neuroscience and biobehavioral reviews January 23, 2021
- Effect of intrapulmonary tetrahydrocannabinol administration in humans. Journal of Psychopharmacology September 2008
- Effects of acute smoked marijuana on complex cognitive performance. Neuropsychopharmacology November 2001