The effect of five day dosing with THCV on THC-induced cognitive, psychological and physiological effects in healthy male human volunteers: A placebo-controlled, double-blind, crossover pilot trial

Amir Englund*, Zerrin Atakan, Aleksandra Kralj, Nigel Tunstall, Robin Murray, Paul Morrison

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Citations (Scopus)


Rationale: Cannabis is mostly grown under illegal and unregulated circumstances, which seems to favour a product increasingly high in its main cannabinoid Δ-9-tetrahydrocannabinol (THC). Δ-9-tetrahydrocannabivarin (THCV) is a relatively untested cannabinoid which is said to be a cannabinoid receptor neutral antagonist, and may inhibit the effects of THC. Objectives: To explore the safety and tolerability of repeated THCV administration and its effects on symptoms normally induced by THC in a sample of healthy volunteers. Methods: Ten male cannabis users (<25 use occasions) were recruited for this within-subjects, placebo-controlled, double-blind, cross-over pilot study. 10mg oral pure THCV or placebo were administered daily for five days, followed by 1mg intravenous THC on the fifth day. Results: THCV was well tolerated and subjectively indistinguishable from placebo. THC did not significantly increase psychotic symptoms, paranoia or impair short-term memory, while still producing significant intoxicating effects. Delayed verbal recall was impaired by THC and only occurred under placebo condition (Z=-2.201, p=0.028), suggesting a protective effect of THCV. THCV also inhibited THC-induced increased heart rate (Z=-2.193, p=0.028). Nine out of ten participants reported THC under THCV condition (compared to placebo) to be subjectively weaker or less intense (χ2=6.4, p=0.011). THCV in combination with THC significantly increased memory intrusions (Z=-2.155, p=0.031). Conclusion: In this first study of THC and THCV, THCV inhibited some of the well-known effects of THC, while potentiating others. These findings need to be interpreted with caution due to a small sample size and lack of THC-induced psychotomimetic and memory-impairing effect, probably owing to the choice of dose.

Original languageEnglish
Pages (from-to)140-151
Number of pages12
JournalJournal of psychopharmacology (Oxford, England)
Issue number2
Early online date17 Nov 2015
Publication statusPublished - 1 Feb 2016


  • cannabinoid
  • cannabis
  • human
  • memory
  • psychosis
  • THC
  • THCV
  • Δ9-tetrahydrocannabinol
  • Δ9-tetrahydrocannabivarin

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