AUSTIN, Texas -- Lawyers who used an "affluenza" defence for a Texas teenager in a fatal 2013 drunken-driving wreck have failed to secure his release from jail.

The Texas Supreme Court denied the request Thursday for 20-year-old Ethan Couch, who was 16 when his crash killed four people near Fort Worth.

Couch received 10 years' probation after pleading guilty to intoxication manslaughter and other juvenile charges. A defence expert used the term "affluenza" during trial, suggesting Couch was coddled into a sense of irresponsibility by his wealthy parents.

After an online video appeared to show Couch at a party where people were drinking, Couch and his mother briefly fled to Mexico in December 2015. A judge then moved the case to adult court, ruled Couch violated his probation and imposed the jail sentence that Couch's attorneys challenged.