If Not Drugs, What Killed Amy Winehouse?

Aug. 24, 2011— -- Amy Winehouse's family revealed Tuesday that "no illegal substances" were found in her body at the time of her death.

Their bombshell announcement has many people wondering if drugs didn't kill the "Rehab" singer, what did?

In Tuesday's statement, the family said: "Toxicology results returned to the Winehouse family by authorities have confirmed that there were no illegal substances in Amy's system at the time of her death. Results indicate that alcohol was present, but it cannot be determined as yet if it played a role in her death."

Winehouse was found dead in her London flat July 23. She was 27. The formal cause of death remains unknown and will be not be released until October.

But Pittsburg forensic pathologist Cyril Wecht cautions against reaching a conclusion from the family's statement.

"The fact that the family said no illicit drugs were found does not mean in and of itself other drugs obtained legally were not found," Wecht told ABCNews.com. "Most drug deaths are from legally obtained drugs. That's one caveat I would express in regard to the family's statement."

Bruce A. Goldberger, a toxicology professor at the University of Florida, said some prescription drugs, illicit drugs and "designer" drugs can escape detection.

If drugs weren't directly to blame, they could have played an indirect role in Winehouse's death.

"I think the picture that we get by studying Amy Winehouse and her behavior is so different than some of the other stars that we've lost, including Heath Ledger," Goldberger told ABCNews.com. "This lifestyle that she lived could have resulted in her death, even though drugs were not found at the time of autopsy."

Winehouse's longtime abuse of drugs and alcohol was well documented, though officials reportedly found no drug paraphernalia or sign of drugs in her home.

Around the time of her hit album's release, the singer admitted in several interviews that she suffered from manic depression and would self-medicate.

"I do drink a lot. I think it's symptomatic of my depression," Winehouse said in an interview on the British TV show, "The Album Chart Show." "I'm manic depressive, I'm not an alcoholic, which sounds like an alcoholic in denial."

The years of abuse could have taken their toll.

"The misuse/abuse of illicit drugs as well as prescription drugs can lead to cardiovascular disease and other changes in the body that can lead to death," Goldberger said. "Alcohol abuse can cause similar changes."