Before the opening of "A Merry Friggin' Christmas," Robin Williams's autopsy revealed that he did not take alcohol or illegal drugs when he hanged himself in August at his Northern California home, Yahoo reported.
According to the autopsy report the Marin County sheriff's office released, the prescription medications the late actor had taken were in "therapeutic concentrations." Marin County coroner Robert Doyle ruled his death a suicide caused by "asphyxia due to hanging."
"Toxicological evaluation revealed the absence of alcohol or illicit drugs. Prescription medications were detected in therapeutic concentrations. His prior medical history reportedly included depression, Parkinson's Disease and a recent increase in paranoia," the report stated.
The report added that before Williams committed suicide, he was having trouble sleeping and showed increased signs of paranoia.
His wife Susan Schneider confirmed to an investigator that shortly before his death, he entered a substance-abuse program to reaffirm the principles of his rehabilitation and not because of alcohol or drug abuse, Washington Post reported.
Before his death, Williams filmed "A Merry Friggin' Christmas," which premiered at the Carmel International Film Festival in October and recently hit select theaters in the United States.
Directed by Tristram Shapeero and written by Michael Brown, "A Merry Friggin' Christmas" also stars Joel McHale, Lauren Graham, Wendi McLendon-Covey, Jeffrey Tambor, Matt Jones, Pierce Gagnon, Candice Bergen and Oliver Platt.
"If someone said to me, 'You're going to be in a Robin Williams movie and are going to be playing his son,' I'd say, 'I must have won some sort of lottery.' It was something I always dreamed of and when I got to do it," McHale told ABC News.
"I think the way the world loved him was pretty rare. I went to his funeral and it was one of the sadder things I've been to in a long time. I will miss him terribly," Hale said of Williams, whom he described as amazing, giving, kind and cool.