Medications offer modest help; vaccines are in development.
Illegal stimulants include cocaine, methamphetamine (also known as speed, meth, ice, or crank), and methylenedioxymethamphetamine (often called MDMA or ecstasy). These are among the most commonly abused drugs in the world — and also some of the toughest for addicts to quit.
The Substance Abuse and Mental Health Services Administration estimates that in 2007, about 22 million Americans 12 and older met the criteria for substance abuse or dependence as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Of that total, 1.6 million were dependent on cocaine, while 406,000 were dependent on other types of stimulants. High rates of stimulant abuse have also been reported in Europe.
Prescription stimulants such as methylphenidate (Ritalin, Concerta) and dextroamphetamine (Adderall) are used to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy, but they can also be abused. Some people crush, snort, or inject these drugs, which creates a euphoric sensation. In 2007, about 1 million Americans reported using prescription stimulants for such nonmedical purposes.
Current treatment options
Addicts who want to quit using cocaine or other stimulants face a formidable task. Psychotherapy remains a foundation for treatment of addiction to cocaine or other stimulants. In addition, clinicians may prescribe medications marketed for other health problems. As yet, no medication is FDA-approved for cocaine or stimulant addiction, although new compounds are always being tested.
Behavioral therapies. Various psychosocial interventions offer techniques to help addicts "unlearn" an addiction, learn ways to resist cravings, and slowly build a drug-free life. Options include:
cognitive behavioral therapy, which helps patients to recognize and avoid drug triggers, and then learn new ways of coping without drugs
contingency management, which uses tangible rewards and incentives — such as vouchers that can be exchanged for movies or dinner — to encourage abstinence
the Matrix Model, which combines behavioral therapy, family education, individual counseling, a 12-step self-help program, and drug testing.
Disulfiram. This medication is approved for treating alcohol dependence, but six randomized clinical studies suggest that disulfiram (Antabuse) may also help reduce cocaine use. Patients who use cocaine while taking disulfiram report anxiety, paranoia, and lack of euphoria. Although some clinicians are concerned about side effects, a review concluded that disulfiram is generally safe as long as it is prescribed at doses of 250 mg or less per day. The most common side effects included headaches, fatigue, sleepiness, and anxiety. The authors recommend against using disulfiram to treat cocaine addiction in patients with serious cardiovascular or liver problems, or in those with multiple mental disorders.
Baclofen. One randomized placebo-controlled study reported that the muscle relaxant baclofen (Lioresal), combined with drug abuse counseling sessions, reduced cocaine use in patients. The most dramatic reductions were achieved in patients who had reported the highest levels of cocaine use upon entry into the study. This medication is also being investigated for treating methamphetamine addiction. Another randomized placebo-controlled study has been published, reporting that baclofen provided a slight, but not statistically significant, advantage over placebo in reducing methamphetamine use.
Topiramate. Two preliminary studies reported that the anticonvulsant topiramate (Topamax) helped patients addicted to cocaine remain abstinent or reduce cravings while participating in behavioral therapy. But a review of studies of topiramate and other anticonvulsants conducted by the Cochrane Collaboration concluded that there was not enough evidence to support the use of these medications in treating cocaine addiction.
Modafinil. Preliminary research suggested that the stimulant modafinil (Provigil), which is approved for treating narcolepsy and other sleep disorders, reduced cravings for amphetamines or cocaine. Other research suggests that the drug may help delay the type of impulsive reaction that underlies addiction. But a 2007 review of randomized studies of modafinil and other stimulants concluded modafinil had not performed better than placebo — although the authors recommended further research.
Vaccines in development
Researchers have been working on anti-addiction vaccines since 1974. Four formulations — three for nicotine addiction and one for cocaine addiction — have reached phase I and phase II clinical trials. Phase III trials are planned; other vaccines are in development.
Drug vaccines are designed to enable immune system antibodies to recognize and bind to drug molecules, so that they become too large to penetrate the blood-brain barrier. The hope is that this may help to reduce the pleasurable effects of drug use and subsequent cravings.
The cocaine vaccine, TA-CD, combines an inactivated cholera toxin B protein with an inactivated cocaine molecule, so that a patient's antibodies learn to recognize both, but the person injected with the vaccine is not in danger of becoming ill from cholera. Although the approach holds promise, it is still unproven and the research is in the early stages.
Researchers are also investigating passive immunization by injection of drug-specific monoclonal antibodies, rather than trying to stimulate the immune system to make its own antibodies. Monoclonal antibodies to methamphetamine are being tested in laboratory cell lines and in animals.
Given the pace of drug discovery, it is unlikely any of these vaccines will reach the market soon. In the meantime, behavioral therapies combined with medication trials offer the best hope of recovery.
Orson FM, et al. "Substance Abuse Vaccines," Annals of the New York Academy of Sciences (Oct. 2008): Vol. 1141, pp. 257–69.
Vocci FJ, et al. "Medication Development for Addictive Disorders: The State of the Science," American Journal of Psychiatry (Aug. 2005): Vol. 162, No. 8, pp. 1432–40.
For more references, please see www.health.harvard.edu/mentalextra.
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