A Texas teenager sentenced to probation for causing a fatal drunken-driving crash was taken into custody late Monday in Mexico, where authorities believe he and his mother fled after he may have violated terms of his probation. Ethan Couch received the light sentence after his attorneys said he suffered from "affluenza," which drew widespread ridicule.

Here's an explanation of the term:

WHAT'S AFFLUENZA?

The term was used by a psychologist testifying for the defense during the sentencing phase of Couch's trial in juvenile court. The expert argued that Couch's wealthy parents had coddled and pampered their son into a sense of irresponsibility — a condition the expert termed "affluenza" — to the point that Couch never developed a sense of right and wrong, or suffered any repercussions for bad behavior.

WHAT DO MEDICAL PROFESSIONALS THINK?

Affluenza is not recognized as a medical diagnosis by the American Psychiatric Association, and its invocation during Couch's trial attracted backlash from some medical experts and families of the four people killed in the crash. The Diagnostic and Statistical Manual of Mental Disorders, published by the association, is widely used by mental health professionals and makes no mention of affluenza.

Dr. Jeffrey Metzner, a forensic psychiatrist and clinical professor at the University of Colorado at Denver, said there are some similarities to the clinical diagnosis of narcissistic personality disorder. A person with that disorder feels entitled and doesn't care about other people's needs, he said.

But he noted that U.S. law doesn't recognize narcissism as a legitimate defense.

WHERE DOES THE TERM COME FROM?

The term "affluenza" was popularized in the late 1990s by Jessie O'Neill, the granddaughter of a past president of General Motors, when she wrote the book "The Golden Ghetto: The Psychology of Affluence." It's since been used to describe a condition in which children — generally from richer families — have a sense of entitlement, are irresponsible, make excuses for poor behavior, and sometimes dabble in drugs and alcohol.

Affluenza appears to have entered the pop culture lexicon as a combination of two words: affluent and influenza. A website called The Affluenza Project bills itself as a resource for understanding the effects of money on relationships. Various books on the subject theorize that affluence often doesn't translate into happiness or that it leads to overconsumption and a growing sense of alienation and distress.

HAS AFFLUENZA BEEN USED IN OTHER LEGAL CASES?

Shortly after Couch's trial, a supervising attorney at the University of Texas at Austin's Criminal Defense Clinic said had never heard of affluenza. Richard Segura, who wasn't involved in the case, told The Associated Press in late 2013 that invoking such a defense likely wouldn't lessen any punishment, but said Couch's defense attorney likely would have looked at all the facts in the case and tailored them in a way that he thought would best influence the judge's decision.