Robin Williams’ autopsy found no alcohol or illegal drugs were in his body when he killed himself at his Northern California home in August, sheriff’s officials said Friday. The autopsy results released by the Marin County sheriff’s office found that the actor had taken prescription medications, but in “therapeutic concentrations.” The coroner ruled Williams’ death a suicide that resulted from asphyxia due to hanging. Williams’ wife, Susan Schneider, has said the actor and comedian was struggling with depression, anxiety and a recent Parkinson’s diagnosis. Williams had publicly acknowledged periodic struggles with substance abuse. He had entered a substance abuse rehabilitation program shortly before his death.