Whitney Houston's death at age 48 is reportedly the result of drug and alcohol abuse.

Houston had entered addiction treatment at least three times. Each effort at recovery was followed by relapse.

Why do people with addictions so often relapse? What is addiction, and what does it mean to recover?

WebMD asked two experts in the field: Ihsan Salloum, MD, MPH, professor of psychiatry and chief of the division of alcohol and drug abuse at the University of Miami Miller School of Medicine; and Bruce Goldman, LCSW, director of substance abuse services at Zucker Hillside Hospital, Glen Oaks, N.Y.

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What Is Addiction?

Experts think of addiction as a long-lasting, often relapsing brain disease, Salloum says.

"It is a chronic disease. It is an ongoing illness," Salloum tells WebMD. "People can recover, but they are always at risk of relapse."

Imaging studies document changes in the brains of people addicted to various substances. The brain's pleasure/reward circuit is affected.

"The drug hijacks those circuits," Salloum says.

How Is Addiction Treated?

Most of us are familiar with 12-step programs such as Alcoholics Anonymous. Such programs, which offer intensive community support, can be very effective.

But ultimately, the most effective addiction treatment varies from person to person, says substance abuse treatment expert Goldman.

"Treatment is a very personal choice," Goldman tells WebMD. "Nowadays there are many options: medications, individual psychotherapy, group therapy, family therapy, behavior modification therapy, contingency management, a whole menu of choices, including self-help groups and meetings, that are very helpful to many people."

What works best?

"Addiction treatment can take whatever form is best for an individual," Goldman says. "We understand it is not one size fits all. And the treatment community has worked hard to customize treatment to each person's particular needs."

Salloum says that medications, some targeted to specific addictive substances, can help reduce cravings and make other forms of treatment more effective.

But ultimately, Goldman says, the best predictor of treatment success is how long an addicted person stays in treatment.

"My message is, it is important to get help and stay in help as long as possible," he says. "The longer people stay in treatment, the better their chances."

Salloum notes that even inpatient treatment often is too short. Many insurers reimburse only for a 28-day course of inpatient treatment, but he says a 90-day inpatient treatment course offers better odds of recovery.

Why Is Addiction Relapse So Common?

Addictions are for life. But life isn't always a smooth course. Stress inevitably comes along.

"The whole stress system is linked to the reward system, which has been hijacked by the addiction," Salloum says. "When addicted people are faced with stress they cannot cope with, they are at high risk of relapse."

Why Is Addiction Relapse So Common? continued...

When one thinks of addiction as a chronic disease, such as diabetes or heart disease, relapse is easier to understand.

"The goal is abstinence and long-term recovery, but we understand it may not be a straight line to that goal," Goldman says. "People with diabetes may sometimes have too-high blood sugar, but one high reading does not mean they are failing treatment."

Unfortunately for people battling addiction, any single relapse can be deadly.

If relapse isn't fatal, addicts who go back into recovery can learn from their mistakes.

"Relapse really could be part of this recovery process. It is a fine line," Goldman says. "You don't want to send the message that it is OK to relapse. People die when they relapse. Others never come back to treatment. It is very dangerous. But if people do relapse, we need to take that opportunity to move them forward to the next phase of their recovery."

Is Addiction More Common -- Or More Deadly -- to Celebrities?

Time after time we learn of celebrities who fall victim to addictions. They go into rehab. They relapse. Many -- too many -- die too young.

There are two sides to the issues faced by celebrities with addictions, Goldman says.

Being in the limelight, not having anonymity, having the pressure of every move you make being public has to take its toll," he says. "Expectations are high for each performance, and you have unlimited resources to buy drugs, people to provide them, and doctors to prescribe medications."

On the other hand, celebrities are able to get the best care available.

But in the end, celebrities are people. The unhappy truth is that many people have substance abuse problems.

"Celebrities are visible and public, but at the end of the day, all of us know someone who has suffered from an addictive disease," Goldman says. "And their suffering and that of their families has been equally dramatic as what we see in celebrities."

There is, however, a silver lining to celebrity addiction deaths. Shocked into action, addicts and their families seek help.

"We have to take these public events and translate them into action," Goldman says. "If people we know, maybe ourselves, suffer from chemical dependency, there is help. And with help, people do get better."