Douglas had a history of drink and drug problems

Eric Douglas' death was caused by an "acute intoxication" by the effects of alcohol, tranquilisers and painkillers, the medical examiner's office said.

Douglas, who had suffered from drink and drug problems, was found dead in a Manhattan apartment on 6 July.

A spokesman for the Douglas family declined to comment.

The 46-year-old was an aspiring actor and comedian, but did not find the success his father or his half-brother, Michael Douglas, had enjoyed.

He appeared in television shows and movies such as Delta Force 3, and also worked as a stand-up comedian.

But he admitted finding it difficult to follow in the footsteps of his famous family, and struggled with drug and alcohol addiction while suffering from legal troubles.

In 1997, he pleaded guilty to cocaine possession after being arrested for accepting a package of more than 1,000 anti-depressant pills.

In 2000, he admitted spending eight days in a coma after a drug overdose the previous year, which had affected his speech.