• Claudine C Hunault, Koen B E Böcker, R K Stellato, J Leon Kenemans, Irma de Vries, and Jan Meulenbelt.
• National Dutch Poisons Information Center, University Medical Center Utrecht, PO Box 85500, 3508, GA, Utrecht, The Netherlands, c.hunault@umcutrecht.nl.
• Psychopharmacology (Berl.). 2014 Dec 1; 231 (24): 4723-33.

RationaleAn increase in the potency of the cannabis cigarettes has been observed over the past three decades.ObjectivesIn this study, we aimed to establish the impact of Δ9-tetrahydrocannabinol (THC) on the rating of subjective effects (intensity and duration of the effects), up to 23 % THC potency (69 mg THC) among recreational users.MethodsRecreational users (N = 24) smoked cannabis cigarettes with four doses of THC (placebo 29, 49 and 69 mg of THC) on four separate test days in a randomized, double-blind, placebo-controlled, crossover study. The participants filled in three different questionnaires measuring subjective effects during the exposure up to 8 h post-smoking. The 'high' feeling, heart rate, blood pressure and THC serum concentrations were also regularly recorded during these 8 h.ResultsTHC significantly increased the high feeling, dizziness, dry-mouthed feeling, palpitations, impaired memory and concentration, and 'down', 'sedated' and 'anxious' feelings. In addition, THC significantly decreased alertness, contentment and calmness. A cubic relationship was observed between 'feeling the drug' and 'wanting more'. The THC-induced decrease in 'feeling stimulated' and increase in anxiety lasted up to 8 h post-smoking. Sedation at 8 h post-smoking was increased by a factor of 5.7 with the highest THC dose, compared to the placebo.ConclusionsThis study shows a strong effect of cannabis containing high percentages of THC on the rating of subjective effects. Regular users and forensic toxicologists should be aware that the THC-induced increase in 'feeling sedated' continues longer with a 69 mg THC dose than with a 29 mg THC dose.

30 keywords...

hide…