THC Sensitivity Recovered Differently for Food and Shock-Termination Responding

After chronic THC stopped, sensitivity was no longer significantly different from baseline on one response-rate measure but remained reduced on another. Recovery depended on the measured behavior.

Both outcomes came from the same chronic-treatment comparison

McMahon assessed three rhesus monkeys responding for food and stimulus-shock termination. Challenge testing before, during and after repeated THC allowed each response to be compared with its own earlier drug sensitivity.

Recovery was substantial but not uniform

After discontinuation, THC sensitivity in the food component was no longer significantly different from its pre-treatment value. In the shock-termination component, sensitivity remained significantly reduced, with a reported 5.1-fold potency shift, although the shift was much smaller than during treatment.

Nonsignificance is not exact restoration

The food finding does not prove identical sensitivity in every animal or exclude a residual difference in this small sample. The persistent effect on the other component likewise does not establish permanent adaptation. These observations concern injected THC and learned primate responses. They support an outcome-specific account of recovery, not a universal abstinence interval after which cannabis tolerance, cognition or driving performance is guaranteed to reset.

Related: Interpreting cannabinoid tolerance evidence.

Research cited

Lance R. McMahon. Chronic Δ9-tetrahydrocannabinol treatment in rhesus monkeys: differential tolerance and cross-tolerance among cannabinoids (2011).