clift's body was taken to the city morgue less than two miles away at 520 first avenue, and autopsied. the autopsy report cited the cause of death as a heart attack brought on by "occlusive coronary artery disease". no evidence was found that suggested foul play or suicide. it is commonly believed that drug addiction was responsible for clift's many health problems and his death. in addition to lingering effects of dysentery and chronic colitis, an underactive thyroid was later revealed during the autopsy. the condition (among other things) lowers blood pressure; it may have caused clift to appear drunk or drugged when he was sober, and also raises cholesterol, which may have contributed to his heart disease.