Alcohol and Xanax, both found in Whitney Houston’s hotel room right after she died, inhibit the central nervous system and depend on the same enzyme for bodily clearance

The mystery of Whitney Houston’s death will not be solved for several weeks, as the Los Angeles County Coroner’s Office awaits a full toxicology report. But many experts speculate that the singer’s tragic demise involved a deadly cocktail of alcohol and prescription drugs, including Xanax.

Houston wouldn’t be the first star to suffer such a fate: Heath Ledger, Michael Jacksonand Anna Nicole Smith are all thought to have died in part from prescription drug overdoses, which can involve painkillers, sedatives and stimulants, often in combination with alcohol. But the problem extends far beyond Hollywood. In 2007 some 27,000 Americans died from unintentional prescription drug overdoses—making prescription drugs a more common cause of accidental death in many states than car crashes are.

A slippery slope
Although sedatives are thought to have played a role in Houston’s death, most prescription drug overuse involves opioid painkillers.Approximately 3 to 5 percent of people who take pain medication eventually end up addicted, according to Nora Volkow, director of the National Institute on Drug Abuse, an arm of the U.S. National Institutes of Health. And “individuals who have a past history of a substance-use disorder—from smoking, drinking or other drugs—are at greater risk,” she says. Addiction to other classes of prescription drugs such as sedatives, stimulants and sleepmedications is thought to be less common—but it occurs, and even users who do not become compulsively addicted can, over time, become physically dependent and experience intense withdrawal symptoms when their prescriptions run out. They might also develop drug tolerance, the need to take higher doses over time to feel the same effects.

Other people start taking prescription drugs just to get high, perhaps in part because they have the (false) notion that prescription drugs are safer to experiment with than are illicit drugs. “They take them for recreational purposes, and then a portion of them find ‘Wow, I can’t stop using this,’” says Jon Morgenstern, director of addiction treatment at the Columbia University Medical Center