February 14, 2006 -- A research update from the National Institute on Drug Abuse shows that methamphetamine abuse is a significant problem in the United States, however there is hope for the future.

• Approximately 12
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 million people 12 years and older have abused methamphetamine in their lifetimes; in 2004, approximately 600,000 were current users (NSDUH).
• Abuse appears to be increasing in certain areas of the country, especially rural communities.
• According to NIDA’s 2005 Monitoring the Future Survey, there have been significant decreases between 2004 and 2005 in methamphetamine abuse among 10th and 12th graders (Figure 1).
• Methamphetamine’s potent addiction liability and destructive health and social consequences make its abuse particularly dangerous.

Methamphetamine acts by increasing the release of dopamine in the brain, which leads to feelings of euphoria. However, this influx of pleasure is followed by a “crash” that often leads to increased use of the drug and eventually to difficulty feeling any pleasure at all, especially from natural rewards. Long-term methamphetamine abuse also results in many damaging
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 physical and psychiatric effects, such as:

• Addiction
• Violent Behavior
• Anxiety
• Confusion
• Insomnia
• Psychotic features (e.g. paranoia, hallucinations, delusions)
• Cardiovascular problems (e.g. rapid heart rate, irregular heartbeat, increased blood pressure, stroke)


What Does Methamphetamine Do to the Brain?

Methamphetamine’s adverse effects on the brain are clear. In animals, methamphetamine damages nerve terminals in brain regions containing dopamine and serotonin, two chemicals essential for normal functioning of the central nervous system. Similarly, in humans, methamphetamine alters the brain in ways that impair decision-making, memory, and motor behaviors, and causes structural and functional deficits in brain areas associated with depression and anxiety. Dopamine cell death, however, has not been documented
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 in methamphetamine abusers, which could explain why extended abstinence allows for some recovery from methamphetamine-induced deficits in dopamine function (Figure 2). But even though a recent neuroimaging study of methamphetamine abusers showed partial recovery of brain function in some regions following protracted abstinence, function in other regions did not display recovery even after two years of abstinence—suggesting that long-lasting and even permanent brain changes may result from methamphetamine abuse.
 
Methamphetamine and HIV

In addition to its harmful effects on the brain, methamphetamine is inextricably linked with HIV, hepatitis C, and other sexually transmitted diseases. Its abuse increases the risk of contracting HIV not only through the use of contaminated injection equipment, but also through increased risky sexual behaviors and through physiological changes that may favor HIV transmission.

Methamphetamine abuse may also affect HIV disease progression. For example, clinical studies suggest that current methamphetamine abusers on highly active antiretroviral therapy may be at greater risk of developing AIDS than non-users, possibly due to poor medication adherence or interactions between methamphetamine and HIV medications. Similarly, preliminary studies suggest that interactions between methamphetamine and HIV itself may lead to more severe consequences for HIV-positive patients who abuse methamphetamine, including greater brain damage and cognitive impairment. More research is needed to better understand these interactions.

Treatments for Methamphetamine Addiction

Methamphetamine addiction can be successfully treated. The Matrix Model, a proven effective treatment for methamphetamine addiction, consists of a 16-week intervention that includes intensive group and individual therapy to promote the behavioral changes needed to remain off drugs, prevent relapse, and establish a new lifestyle unrelated to drugs. When applied to methamphetamine abusers, the Matrix Model has been shown to significantly reduce drug use (Figure 3).

Motivational Incentives for Enhancing Drug Abuse Recovery (MIEDAR), an incentive-based method for cocaine and methamphetamine abstinence, is another treatment program that has recently demonstrated efficacy in methamphetamine abusers through NIDA’s National Drug Abuse Clinical Trials Network.

NIDA is also developing medications for methamphetamine addiction. In 2000, NIDA established the Methamphetamine Clinical Trials Group (MCTG) to conduct clinical (human) trials of medications for methamphetamine addiction in geographic areas in which its abuse is particularly high, including San Diego, Kansas City, Des Moines, Costa Mesa, San Antonio, Los Angeles, and Honolulu. For example, modafinil, which is used to treat narcolepsy, has shown promise in cocaine treatment and may aid in methamphetamine treatment. Given modafinil’s positive effects on executive function and impulsivity, the MCTG is currently testing the compound’s ability to complement behavioral counseling in treating methamphetamine abuse. Another potential treatment is the anti-epileptic medication, gamma-vinyl GABA (GVG). Studies have demonstrated the efficacy of GVG in helping methamphetamine addicts remain drug free for more than a month, despite living in their normal home environment with ready access to drugs. To treat methamphetamine overdose, NIDA is also developing antibodies to methamphetamine that will bind the drug in the bloodstream and prevent its deleterious effects.

For further information please visit NIDA.