Scott had no serious medical conditions, including cancer, at the time of his death, the Los Angeles Times said Monday.
Police told the newspaper they still don't have a clear motive for why he killed himself in August at the age of 68.
Rumors circulated after Scott's suicide saying the native Englishman was suffering from a brain tumor, but his family has vehemently denied the speculation.
Therapeutic levels of the sleep aid Lunesta and the anti-depressant mirtazapine were found in his system, the Times said toxicology tests showed.
Scott frequently worked with actors Tom Cruise and Denzel Washington. Among his films were "Top Gun," "Beverly Hills Cop II," "Days of Thunder," "The Last Boy Scout," "True Romance," "Crimson Tide," "Enemy of the State," "Spy Game," "Deja Vu," "The Taking of Pelham 123" and "Unstoppable."