THC Reduced Amphetamine Hyperactivity but Prolonged Stereotyped Movements in Rats
A 1977 rat study found that THC weakened some amphetamine effects while strengthening or prolonging others. Reduced general activity therefore did not mean the combination reduced every stimulant-related behavioral effect.
Activity and stereotypy were different outcomes
THC dose-dependently reduced amphetamine-stimulated movement and opposed an amphetamine-related temperature rise. At higher amphetamine conditions, however, stereotyped movements lasted longer with THC. Those repetitive behaviors should not be merged with an overall activity count.
Other combination effects also persisted
Both compounds reduced food and water intake and body-weight gain, with additive effects in combination. Brainstem dopamine content increased more under the combination than under either reported individual condition. Tissue content is not a direct measure of dopamine release or proof of a particular subjective experience.
Repeated THC did not remove amphetamine effects
Tolerance developed to the tested THC effects, but the study did not find cross-tolerance to amphetamine's pharmacological and biochemical effects. Thus, adaptation to THC did not establish generalized resistance to a stimulant challenge.
The experiment demonstrates why drug interactions need separate behavioral, physiological and biochemical endpoints. It does not establish THC as a way to counter stimulant effects or make combined use safe. Animal doses and tissue measures cannot provide an individual human impairment or toxicity prediction.
Related: interpreting cannabis tolerance claims.
Research cited
Hattendorf C; Hattendorf M; Coper H; Fernandes M. Interaction between delta(9)-tetrahydrocannabinol and d-amphetamine. Psychopharmacology (1977). doi:10.1007/BF00426776. Findings discussed from the study abstract.
