Animal studies suggest that THC has an inhibitory effect on polysynaptic reflexes.
Some spastic patients claim improvement after inhaling cannabis.
We tested muscle tone, reflexes, strength and performed EMGs before and after double-blinded oral administration of either 10 or 5 mg THC or placebo. The blinded examiner correctly identified the trials in which the patients received THC in seven of none cases. Quadriceps EMG interference pattern was reduced in those four patients with primarily extensor spasticity. THC was administered to eight other patients with spasticity and other CNS lesions. No benefit was noted in patients with cerebellar disease.