Actor Robert Downey Jr has thanked US authorities for arresting his 20-year-old son on suspicion of cocaine possession and says the family is determined to get him the help he needs.
Indio Falconer Downey was taken into custody on Sunday afternoon after a car he was riding in was pulled over in West Hollywood, authorities said.
"Unfortunately, there's a genetic component to addiction and Indio has likely inherited it," Robert Downey Jr, who had a series of high-profile drug-related arrests in the late 1990s, said in a statement.
"We're grateful to the Sheriff's Department for their intervention, and believe Indio can be another recovery success story instead of a cautionary tale."
Robert Downey's drug use sent him to prison and rehab and cost him acting roles.
He is now one of the industry's most bankable stars after appearing in Marvel's Iron Man trilogy and The Avengers.
Indio Downey was booked on suspicion of possession of a controlled substance, believed to be cocaine, and possession of drug paraphernalia, sheriff's Sergeant Dave Valentine said.
He was later released after posting US$10,250 (NZ$11,700) bail.
A court date was set for August 29.
Two other people were in the car, but only Downey was arrested.
He appeared in the 2005 movie Kiss Kiss Bang Bang, which starred his father.