Acute effects of THC on time perception in frequent and infrequent cannabis users.
Level 2 - randomized trial
Randomized, double-blind, counterbalanced, placebo-controlled crossover trial
PubMed 23179965 · doi:10.1007/s00213-012-2915-6
What was done
Forty-four participants completed visual time estimation and production tasks in the seconds range during double-blind, randomized, counterbalanced, crossover, placebo-controlled trials. Subjects received intravenous delta-9-tetrahydrocannabinol (THC) at doses ranging from 0.015 to 0.05 mg/kg or placebo, with tasks presented three times per test day. The study evaluated the acute effects of THC across doses and examined whether response differed between frequent and infrequent/non-cannabis users.
What was found
The abstract reports directions of effect without numerical values, effect sizes, or confidence intervals. Intravenous THC induced overall time overestimation and underproduction, but the effects were not dose-related across the 0.015 to 0.05 mg/kg range. Chronic cannabis use did not alter baseline time perception. Infrequent/non-smokers demonstrated temporal overestimation at medium and high doses and temporal underproduction at all doses, whereas frequent cannabis users showed no significant alterations in time perception after THC administration.
Why it matters
This study provides experimental human evidence that acute THC speeds internal clock processing in infrequent cannabis users, while demonstrating behavioral tolerance to these acute temporal distortions in frequent users.
Limits
The abstract provides no numerical data, standard deviations, or p-values. The sample size was modest (n = 44) and pooled across several separate crossover studies. The use of intravenous THC administration excludes the pharmacokinetics of inhaled cannabis and the potential modifying effects of other whole-plant cannabinoids.
Cited by
- supports Cannabis consumption causes people to perceive that a long period of time has passed when only a short period has elapsed.