Dementia-Linked Hallucinations Drove Robin Williams' Suicide According to TMZ's sources By Evann Gastaldo, Newser Staff Posted Nov 11, 2014 8:40 AM CST 17 comments Comments In this Nov. 5, 2011 file photo, actor Robin Williams poses for a portrait during the "Happy Feet" Press Junket in Beverly Hills, Calif. (Photo by Dan Steinberg/Invision/AP) (Newser) – TMZ says it has uncovered what was behind Robin Williams' suicide: a disease called Lewy Body Dementia, which can cause hallucinations. Lewy Body Dementia is commonly associated with Parkinson's, which Williams had, and Radar Online reported last week that Williams' autopsy report revealed that he suffered from it. One symptom is abnormal protein deposits that affect brain function, and people with both Lewy Body Dementia and Parkinson's often experience side effects—like the aforementioned hallucinations—from Parkinson's drugs. Sources connected to Williams' family say that Lewy Body Dementia was the "key factor" behind his suicide, and that his doctors agree. Williams' wife, Susan, reportedly told authorities he'd been complaining about side effects from his medications before his death. According to Radar, Williams didn't know about his Lewy Body Dementia diagnosis when he died, but he was having difficulty sleeping and was "restless due to his Parkinson’s and anxiety issues, which is why he was sleeping in a separate bedroom" from Susan, according to the autopsy report. He was sleeping in his stepson's room while his stepson was away, and Susan saw him the night before his death. The next day, concerned when he hadn't come out of the room, she slipped a note under the door, the report says, then eventually popped the lock with a paper clip and found Williams. There was nothing found on his iPhone or iPad to suggest he'd been thinking of suicide, but his iPad had "several tabs open to websites discussing medications, including lyrica and propranolol," the report reads. There was no alcohol or illegal drugs in his system.