Is there any negative side-effects from using marihuana and percocet together? I have a rare genetic condition that causes me to be in extreme pain at times. My doctor was prescribing percocet to me for the pain, but after a routine urine test she descovered that I had been using marihuana and now refuses to continue the percocet. She still believes that marihuana is physically as well as psychologically addicting. And, with some people it my be psychologically addictive but physically addictive? I seriously don't beleive so.