Effects of cannabis resin on social behaviour in the laboratory mouse.

The effects of several dose levels of cannabis have been studied by an ethiological analysis of encounters between male mice injected with the drug and partners injected with Tween-saline. The duration of immobility was directly related to the logarithm of the dose of cannabis given. The ratio of flight in the treated animals to aggression in those mice with which they were paired showed a progressive increase as the dose of cannabis was raised from 4-50 mg/kg. A straight line relationship was found to exist between the logarithm of flight/aggression and logarithm of the dose of cannabis administered. Non-social activity and social investigation were decreased by the administration of cannabis; this was due to the time spent by the treated animals in immobility. Aggression was not significantly altered. Many mice given doses of 25-100 mg cannabis/kg showed an ataxic gait and the Straub tail reaction.