Research on the neurobiology of drug addiction is informing new and better ways to treat addiction. Volkow and other researchers have shown that after a period of abstinence from drugs, the dopamine system can repair itself–but it generally takes longer than a year. And while studies have shown that functional skills such as short-term memory and motor control do come back, it’s not clear whether they come back completely.
Given the nature of many of the drug-induced brain changes, experts now see addiction as a chronic disease. Like heart disease or diabetes, diseases for which patients require long-term treatment, patients with addictions require long-term treatment plans. And the occasional relapse is only a predictable setback, not a failure of the treatment, says Volkow.
Experts also now know that the best treatments should target addictive behaviors in several ways. They should, for example, decrease the reward value of the drug, according to Volkow, perhaps by counseling addicts to seek out other pleasurable experiences and to repeat them to reinforce their value in the brain. Avoiding the drug and focusing on other pleasurable experiences will, over time, weaken conditioned memories of the drug and drug-related stimuli.
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Research on the neurobiology of drug addiction is informing new and better ways to treat addiction.
A better understanding of the effects on the brain of substance abuse is also informing efforts to develop medications that can help a person kick the habit. Two popular antismoking drugs, Chantix and Zyban, for example, work by competing with nicotine for binding sites on neurons. By partially activating dopamine release, the drugs help reduce nicotine cravings while a person is trying to quit smoking. They also make smoking less pleasurable because nicotine from cigarettes cannot bind to nicotine receptors while the drugs are present. As a result, smoking becomes much less enjoyable, and therefore easier to stop. Research has shown these medications to be two to three times more effective at aiding smoking cessation compared to placebo. However, there have also been reports of serious side effects of these drugs, such as suicidal thoughts, so use of the medications should be considered carefully.
Scientists are also studying medications that work in different ways. For example, Nabi Biopharmaceuticals, based in Rockville, Maryland, is testing a nicotine vaccine in late-stage clinical trials. According to Nabi, this inhalable vaccine stimulates the immune system to produce antibodies that bind to nicotine, preventing nicotine from reaching receptors in the brain. Smoking then no longer feels pleasurable and smokers should more easily be able to quit. The vaccine has side effects, however, and preliminary results suggest that it is no more effective than Chantix at smoking cessation. Despite these setbacks, researchers haven’t yet given up hope for this approach.
In the end, a combination of behavioral strategies and medications that target specific neurotransmitters or brain circuits will likely work the best to help addicts kick the habit, says Frascella, of NIDA.