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Relapse and Craving

Scientists and medical experts now consider the disease of addiction to be chronic and relapsing. It requires long-term work to recover from addiction, and relapse is common. In this respect, medically, addiction is more like hypertension -- which may require long-term treatment with medication and lifestyle changes, and which often recurs -- than a broken bone, which is set, heals, and is forgotten.


Craving in the Brain

When addicted people are shown cues related to their cocaine use, and they experience craving, PET scans show that specific areas of their brains are activated.

Alan Leshner, Ph.D., director of the National Institute on Drug Abuse (NIDA), says that it is not reasonable to expect that drug addicts will obtain lifelong abstinence with the first treatment experience. "Just like the diabetic, [an addict] can be given tools to manage the craving, to manage the compulsion; but every once in a while another treatment may be needed," he says. "Even if [addicts] are treated successfully, often there will be occasional relapses." Neuropharmacology professor George Koob, M.D., of the Scripps Research Institute in La Jolla, California, agrees. He estimates that 80 percent of addicts who get off drugs in detoxification go back to drugs within a year. Only 20 percent achieve a stable abstinence from a given detoxification.

Figuring out why addicts are so prone to relapse is a major area of research. One culprit is the phenomenon of craving, or the powerful "hunger" for drugs that can linger months or years after an addict quits using. Scientists have discovered evidence that this craving may be partly a physiological phenomenon, related to the long-term changes in brain function that addiction causes. Now accustomed to functioning in the presence of drugs, the addicted brain, in essence, has become unable to function normally in their absence.

Craving is also partly a conditioned response to powerful cues to use drugs that the (recovering) addict may encounter, such as people, places, and things that are associated with drug use, Leshner says. These cues evoke powerful emotional memories of the "high," and can trigger near-irresistible urges to use. "Even in the absence of drugs, associated stimuli become capable of producing drug craving," he adds. People recovering from addiction usually are therefore advised to avoid friends and locations that have previously been associated with using drugs. "When something is highly rewarding, we are likely to remember it vividly and also to remember the circumstances under which we encountered it," says Steven Hyman, M.D., director of the National Institute of Mental Health. "Even after years of abstinence, people may experience profound cravings and risk relapse if placed in the surroundings of their former drug use."

Charles O'Brien, M.D., Ph.D., a professor and chief of psychiatry at the University of Pennsylvania Veterans Medical Center, says studies have shown the precise effect of environmental cues in triggering physical "anticipatory reactions" in addicts, such as changes in heart rate, blood pressure, and pupil size. (These physical reactions before the drug is even ingested are specific to the type of drug the particular addict used, O'Brien says: Cocaine addicts don't react to stimuli associated with heroin use, and vice versa.)

Conical Regions Activated By Cocaine Cues

Computer imaging of drug craving in the brain of an addict.

Anna Rose Childress, Ph.D., a psychologist who directs the VA Addiction Research Center at the University of Pennsylvania School of Medicine, has used positron emission tomography (PET) scans to see the system of the brain that is involved when craving occurs in cocaine abusers. (See craving animation above.) She has found that particular areas of the limbic system -- the part of the brain, including the hypothalamus and the amygdala, that is linked to emotion and motivation -- "light up" during scans, showing these areas are being activated.

But relapse is usually preceded by other problems that make a recovered addict vulnerable. Most relapses among addicts occur when they are in a "negative mood state," says Leshner. In other words, other things are impacting their lives that lead them back to using drugs, such as the death of someone close, a loss of a job, or other economic or social stresses. A recovering addict isn't likely to relapse simply by reconnecting with their drug-using past or seeing someone get high, says Leshner.

If not halted, however, relapse can plunge addicts back to former levels of drug use. When alcoholics relapse, they often overdrink almost as if they are making up for lost time, experts say. Koob has discovered that when alcohol is removed from addicted rats for three or four days and then returned, the rats will drink 50 percent more than they did before. This phenomenon is not well understood.

However, if caught in time, relapse can be merely a stumble on the pathway to recovery. If the addict identifies why a relapse has occurred, he or she may be better able to avoid it the next time. Part of the recovery process is learning how to avoid, or "talk back to," these urges, situations, and cues, and wait out the cravings until they recede again. The search to identify where and how in the brain drug cravings are produced may also enable scientists to develop useful medical treatments for the phenomenon. Childress says it's important to understand what stimulates these cravings, in order to develop strategies or medications that help recovering addicts avoid relapse.

-- Janet Firshein

Top: PET scans for animation courtesy of Addiction Research Center of the University of Pennsylvania
Bottom: Courtesy of NIDA Brain Imaging Center

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ANIMATIONS | Differences | Crossing the Line | Relapse | Why Drugs? | Similar Effects | Dependence | Vulnerability | Changing Back | Interviews




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