Placebo effect pain perception

This pharmacological evidence obtained in animal models has provided solid experimental support to previous anecdotal, uncontrolled, or prechnical data that suggested a beneficial effect for marijuana when smoked by multiple sclerosis patients to alleviate such symptoms as spasticity, dystonia, tremor, ataxia, and pain (for a review, see Consroe, 1998). In this hne, a clinical trial has recently finalized in the U.K. using oral administration of placebo, cannabis extract, or A -THC in a population of 667 patients with stable multiple sclerosis and muscle spasticity. The results of this trial have suggested that cannabinoids did not have a beneficial effect on spasticity in multiple sclerosis patients but increased the patient s perception of improvement of other signs including pain (Zajicek et al., 2003). 

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