Former methamphetamine users who abstain for extended periods of time may recover some brain function damaged as a result of drug use.
Meth use is known to damage regions of the brain associated with selective attention and memory. However, the study by Thomas E. Nordahl, M.D., Ph.D., of the University of California at Davis and colleagues suggests that the brain may be able to recover from some of the structural and functional neuronal changes wrought by methamphetamine.
The researchers compared brain images of 8 former meth users who had been abstinent for one to five years to scans of 16 people who only recently had quit using meth. Levels of N-acetylaspartate (NAA), a marker for neural activity, were measured to determine the amount of neuron loss in the subjects' brains. Choline (Cho), a substance created when new neural membranes are formed, was measured to estimate neural recovery.
All of those studied had abnormally low levels of NAA; those who had used meth the longest had the lowest NAA levels. The users' length of abstinence did not appear to affect NAA levels.
However, Cho levels did increase with prolonged abstinence. "In the early period following methamphetamine exposure, the brain may undergo several processes leading to increased membrane turnover. The relative Cho normalization across periods of abstinence suggests that when drug exposure is terminated, adaptive changes occur, which may contribute to some degree of normalization of neuronal structure and function," according to the researchers.
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Treatment of addiction to prescription stimulants, such as Ritalin, is often based on behavioral therapies that have proven effective in treating cocaine and methamphetamine addiction. At this time, there are no proven medications for the treatment of stimulant addiction. However, NIDA is supporting a number of studies on potential medications for treating stimulant addiction.
Depending on the patient's situation, the first steps in treating prescription stimulant addiction may be tapering the drug dosage and attempting to ease withdrawal symptoms. The detoxification process could then be followed by one of many behavioral therapies. Contingency management, for example, uses a system that enables patients to earn vouchers for drug-free urine tests. (These vouchers can be exchanged for items that promote healthy living.) Cognitive-behavioral therapy also may be an effective treatment for addressing stimulant addiction. Finally, recovery support groups may be helpful in conjunction with behavioral therapy.
NIDA: National Institute on Drug Abuse |
Cocaine is a powerfully addictive drug. Thus, an individual may have difficulty predicting or controlling the extent to which he or she will continue to want or use the drug. Cocaine's addictive effects are thought to be a result of its ability to inhibit the reabsorption of dopamine by nerve cells. Dopamine is released as part of the brain's system of reward, and is either directly or indirectly involved in the addictive properties of every major drug of abuse.
An appreciable tolerance to cocaine's high may develop, with many addicts reporting that they seek but fail to achieve as much pleasure as they did from their first experience. Some users will frequently increase their doses to intensify and prolong the euphoric effects. While tolerance to the high can occur, users can also become more sensitive (sensitization) to cocaine's anesthetic and convulsant effects, without increasing the dose taken. This increased sensitivity may explain some deaths occurring after apparently low doses of cocaine.
Use of cocaine in a binge, during which the drug is taken repeatedly and at increasingly high doses, leads to a state of increasing irritability, restlessness, and paranoia. This may result in a full-blown paranoid psychosis, in which the individual loses touch with reality and experiences auditory hallucinations.
NIDA: National Institute on Drug Abuse |
