Whitney Houston's Death: Substance Abuse May Have Played Role

Feb. 13, 2012— -- Although full details surrounding Whitney Houston's death are not yet known, forensic experts not involved with the case speculate that the singer may have died from an accidental overdose.

According to TMZ, officials said the singer had water in her lungs at the time of her death, but they haven't determined how much water was present before they can say whether or not she drowned. The singer's body was found in a bathtub, reportedly with her face underwater.

Dr. Cyril Wecht, a forensic pathologist and former coroner of Allegheny County, Penn., said if Houston did drown, she would likely have been heavily under the influence of numerous drugs to not wake up after she slipped underwater. He explained that the body has a physiologic need to breathe and will respond reflexively if the head is submerged underwater.

"If you are deeply unconscious to the point of a deep stupor, then it is conceivable that there was a heavy concentration of drugs," he said. Wecht said he has performed about 300 autopsies in the past year and a significant percentage of them have involved overdose deaths.

The average number of drugs involved in those cases, he said, was about five or six that were mixed.

And addiction experts also believe that her struggles with substance abuse played role in her death, and although she entered rehab multiple times, she was likely unable to break the cycle of relapse and recovery that traps many addicts.

Relapse is very common, especially with alcohol and cocaine, which Houston admitted abusing.

"Addiction is considered a chronically relapsing disorder," said Warren Bickel, director of the Advanced Recovery Research Center at the Virginia Tech Carilion Research Institute.

There are also reports that Xanax and Valium were found in Houston's hotel room on the night she died. Both drugs are commonly used to treat anxiety and are also used during substance abuse treatment. They belong to the drug class known as benzodiazepines, which can be highly addicting.

"What often happens with illegal drug addiction is that the treatment involves legal drugs which can be even more challenging to quit," said Alesandra Rain, co-founder of Point of Return, an organization that helps with recovery from prescription drug addiction. "Because Xanax is legal, it gives many the false sense that they are safe."

Previous studies looking at relapse rate among addicts found that between one-third and two-thirds of people who sought treatment for cocaine addiction used the drug again. A number of studies also found that most alcoholics who were in treatment programs drank again.

The singer's celebrity status could also have contributed to the challenges she faced staying clean and sober.

"Whitney's recovery was made all the more problematic by the national attention she received when her addiction was exposed in the press, and then greatly complicated by having her relapses publicly revealed," said Scott Basinger, director of the Addiction Scholars Program at Baylor College of Medicine.

Although the cause of death hasn't been announced, chronic cocaine use can exact a damaging physiological toll on the cardiovascular system, said Dessa Bergen-Cico, an assistant professor at Syracuse University.

"There is little question that her years of cocaine use would have caused cardiovascular health problems endemic to heavy cocaine use, notably damage to heart muscles, coronary arteries and blood vessels," she said.

The Los Angeles County Coroner's Office said it is awaiting toxicology reports before determining a cause of death, which could take six to eight weeks.

ABC News' Dan Childs contributed to this report.