Oscar winning actor Robin Williams had no alcohol or illegal drugs in his body when he killed himself in August, authorities in California said.
The 63-year-old Williams, whose body was found on August 11 by a personal assistant at his home in Tiburon in the San Francisco area, died of asphyxia due to hanging, the Marin County Sheriff's Office said in a statement on Friday. That was the same finding sheriff's officials made in their preliminary conclusion.
The actor had taken prescription medications, but in "therapeutic concentrations." The statement said.
Williams' wife, Susan Schneider, has said the actor and comedian was struggling with depression, anxiety and a recent Parkinson's diagnosis when his personal assistant found him dead.
Williams had publicly acknowledged periodic struggles with substance abuse, and he had entered a substance abuse programme shortly before his death.
According to the autopsy report, his wife told an investigator Williams was having trouble sleeping and had shown increased signs of paranoia before he committed suicide.
Williams, who was one of the world's most famous stand-up comedians, earned an Oscar for his role in the 1997 drama "Good Will Hunting."