Cannabis is taken as a painkiller but it causes some unpleasant side effects like delusions and impaired mobility.

It has long been known that THC gives people a high by binding to a molecular anchor on cells called the cannabinoid type-1 (CB1) receptor.
Through experiments on mice, Zhang and his team confirmed that if the glycine receptor is absent or if its activity is blocked by another drug, the animals experienced pain in a standard 'tail-flick' test even when given THC, confirming that the drug's pain-relief and psychotropic effects can be decoupled.
"We found that this glycine receptor could be a primary target for developing non-psychoactive forms of cannabis," New Scientist.quoted Zhang as saying.
Source-ANI