An autopsy on actor Robin Williams found no alcohol or illegal drugs in his system when he committed suicide at his northern California home in August.
The Marin County sheriff's office released the autopsy results today. It found Williams had taken prescription drugs, but in "therapeutic concentrations".
The coroner ruled his death a suicide that resulted from asphyxia due to hanging.
Sheriff's officials have said Williams was found in the bedroom of his home on the morning of August 11.
Williams' wife, Susan Schneider, has said the actor and comedian was struggling with depression, anxiety and a recent Parkinson's diagnosis when he was found dead by his personal assistant.
Williams had publicly acknowledged periodic struggles with substance abuse. He had entered a substance abuse rehabilitation programme shortly before his death, and Schneider has said he was sober at the time of his suicide.
Williams' wife was probably at home at the time he killed himself, Marin County sheriff spokesman Keith Boyd has said.
Williams was last seen alive by his wife when she went to bed. She woke up the next morning and left, thinking he was still asleep elsewhere in the house.
Shortly after that, Williams' personal assistant came to the home and became concerned when Williams failed to respond to knocks at a door. The assistant found the 63-year-old actor clothed and dead in a bedroom, according to sheriff's officials.