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

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

  • Department of Psychosis Studies, Institute of Psychiatry, King’s College London, London, UK

Amir Englund, Institute of Psychiatry, King’s College London, 16 De Crespigny Park, SE5 8AF, London, UK. Email: [email protected]

Journal of Psychopharmacology 30(2):p 140-151, February 2016. | DOI: 10.1177/0269881115615104

Rationale:

Cannabis is mostly grown under illegal and unregulated circumstances, which seems to favour a product increasingly high in its main cannabinoid [INCREMENT]-9-tetrahydrocannabinol (THC). [INCREMENT]-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.

Copyright ©2016Sage Publications