The autopsy of actor Robin Williams found no alcohol or illegal drugs in his system when he killed himself in his California home in August. The results were released by the Marin County sheriff's office Friday.

The sheriff's office did say that the comedian had taken prescription medications, but only in "therapeutic concentrations." The coroner had ruled that Williams' death was a suicide and the cause of death was asphyxia due to hanging.

Officials said Williams was found in a bedroom in his home in Tiburon on August 11. He was 63 years old.

Sheriff's deputy Stewart Cowan said that no further information from the report would be released from his office.

His wife, Susan Schneider, said the actor was struggling with anxiety, depression and a recent Parkinson's diagnosis. He was found dead by his personal assistant in his Marin County home.

"Robin spent so much of his life helping others," Schneider said in a statement. "Whether he was entertaining millions on stage, film or television, our troops on the front lines, or comforting a sick child-Robin wanted us to laugh and to feel less afraid."

Williams had publicly said he had previous periodic struggles with substance abuse and had entered a rehabilitation program shortly before he died. Reports that he had been suffering from "a recent increase in paranoia" from his diagnosis and said he was sleeping in a stepson's room because of insomnia and anxiety.

His death certificate, which was obtained by CNN on Aug. 21, said that his ashes were scattered off the coast the day after his death.

The results of this autopsy, including toxicology testing, have been repeatedly delayed. They were originally scheduled to be released on Sept. 20. Marin County officials later pushed the date back to Nov. 3, but was again late. Typically, toxicology reports take around six weeks to complete.