The coroner in Marin County, California has officially ruled actor Robin Williams' death a suicide by asphyxia due to hanging.

No alcohol or illegal drugs were involved, according to the statement released on Friday, reports variety.com.

Williams was found dead Aug 11 at his home in the Northern California town of Tiburon. According to the autopsy report, prescription drugs for Parkinson's disease, anxiety and depression were found at normal levels.

The late actor's family revealed shortly after his death that Williams had been suffering from all three conditions.

"It is our hope in the wake of Robin's tragic passing, that others will find the strength to seek the care and support they need to treat whatever battles they are facing so they may feel less afraid," his wife Susan said at the time.