While the initial autopsy proved inconclusive in the death of Heath Ledger, reports that a variety of antianxiety drugs, along with antihistamines and sleep aids, were found near the star's bed raise troubling questions about possible drug interactions.

Coupled with the recent news claiming that empty baggies—perhaps once filled with a narcotic—and a "suspiciously" rolled-up, powder-coated $20 bill were found in Ledger's apartment, it might not be surprising if the actor's death was somehow caused by some terrible combination of drugs gone awry. Radar spoke with Frank Owen, author of No Speed Limit: The Highs and Lows of Meth. Owen wrote a piece in our February issue about the death of nightlife stalwart Dean Johnson, who overdosed in September.

"It reminds me of Anna Nicole Smith's death; there were antianxiety drugs found in her system. It speaks to the fact that people are taking too many drugs these days, and that even combinations of legal drugs can be toxic. People are taking so many drugs—and some of them go to different doctors, so the doctors don't know what other drugs they've been prescribed—it's not surprising that we're seeing a rise in emergency room visits and fatalities.

"It's impossible to say what happened in this case. I've read that Ledger was battling heroin problems as well. Of course, the DEA won't allow tests for reactions to mixtures between legal and illegal drugs, so we can only speculate. But statistics show that most overdoses are rarely from a single drug; they happen because of a combination of drugs, both legal and illegal."