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Monday, July 29, 2013

Methamphetamine Effects

What are the long-term effects of methamphetamine abuse?


Long-term methamphetamine abuse has many negative consequences, including addiction. Addiction is a chronic, relapsing disease, characterized by compulsive drug seeking and use, accompanied by functional and molecular changes in the brain.



In addition to being addicted to methamphetamine, chronic abusers exhibit symptoms that can include anxiety, confusion, insomnia, mood disturbances, and violent behavior.

They also can display a number of psychotic features, including paranoia, visual and auditory hallucinations, and delusions (for example, the sensation of insects creeping under the skin).

Psychotic symptoms can sometimes last for months or years after methamphetamine abuse has ceased, and stress has been shown to precipitate spontaneous recurrence of methamphetamine psychosis in formerly psychotic methamphetamine abusers.

With chronic abuse, tolerance to methamphetamine's pleasurable effects can develop. In an effort to intensify the desired effects, abusers may take higher doses of the drug, take it more frequently, or change their method of drug intake.

Withdrawal from methamphetamine occurs when a chronic abuser stops taking the drug; symptoms of withdrawal include depression, anxiety, fatigue, and an intense craving for the drug.

PET images showing damage to Dopamine transporters in a meth abuser after 1 months abstinence,  significant reduction in activity compared to normal brain, but after 24 months abstinence,  transporters have nearly returned to normal  
Recovery of Brain Dopamine Transporters in Chronic Methamphetamine (METH) Abusers
Chronic methamphetamine abuse also significantly changes the brain. Specifically, brain imaging studies have demonstrated alterations in the activity of the dopamine system that are associated with reduced motor speed and impaired verbal learning.


Recent studies in chronic methamphetamine abusers have also revealed severe structural and functional changes in areas of the brain associated with emotion and memory, which may account for many of the emotional and cognitive problems observed in chronic methamphetamine abusers.

Fortunately, some of the effects of chronic methamphetamine abuse appear to be, at least partially, reversible. A recent neuroimaging study showed recovery in some brain regions following prolonged abstinence (2 years, but not 6 months).

This was associated with improved performance on motor and verbal memory tests. However, function in other brain regions did not display recovery even after 2 years of abstinence, indicating that some methamphetamine-induced changes are very long-lasting.

Moreover, the increased risk of stroke from the abuse of methamphetamine can lead to irreversible damage to the brain.

Long-term effects may include:

  • Addiction
  • Psychosis, including:
    • paranoia
    • hallucinations
    • repetitive motor activity
  • Changes in brain structure and function
  • Memory Loss
  • Aggressive or violent behavior
  • Mood disturbances
  • Severe dental problems
  • Weight loss

What are the risks of methamphetamine abuse during pregnancy?


Prenatal exposure to methamphetamine may also be a problem in the United States. Although according to the NSDUH, less than 1 percent of pregnant women aged 15-44 had used methamphetamine in the past year, any use among this population is of concern. Unfortunately, our knowledge of the effects of methamphetamine during pregnancy is limited.

The few human studies that exist have shown increased rates of premature delivery, placental abruption, fetal growth retardation, and heart and brain abnormalities.

However, these studies are difficult to interpret due to methodological issues, such as small sample size and maternal use of other drugs. Ongoing research is continuing to study developmental outcomes such as cognition, social relationships, motor skills, and medical status of children exposed to methamphetamine before birth.

Are methamphetamine abusers at risk for contracting HIV/AIDS and hepatitis B and C?


Increased HIV and hepatitis B and C transmission are consequences of increased methamphetamine abuse, not only in individuals who inject the drug, but also in noninjecting methamphetamine abusers.

Among injection drug users, infection with HIV and other infectious diseases is spread primarily through the re-use of contaminated syringes, needles, or other paraphernalia by more than one person. However, regardless of how it is taken, the intoxicating effects of methamphetamine can alter judgment and inhibition and lead people to engage in unsafe behaviors.

Methamphetamine has become associated with a culture of risky sexual behavior, both among men who have sex with men (MSM) and heterosexual populations. This link may be due to the fact that methamphetamine and related psychomotor stimulants can increase libido.

Paradoxically, long-term methamphetamine abuse may be associated with decreased sexual functioning, at least in men.

The combination of injection and sexual risk-taking may result in HIV becoming a greater problem among methamphetamine abusers than among opiate and other drug abusers, something that already seems to be occurring, according to some epidemiologic reports.

For example, while the link between HIV infection and methamphetamine abuse has not yet been established for heterosexuals, data show an association between methamphetamine abuse and the spread of HIV among MSM.

Methamphetamine abuse may also worsen the progression of HIV and its consequences. In animal studies, methamphetamine increased viral replication; in human methamphetamine abusers, HIV caused greater neuronal injury and cognitive impairment compared with nondrug abusers.

NIDA-funded research has found that, through drug abuse treatment, prevention, and community-based outreach programs, drug abusers can change their HIV risk behaviors. Drug abuse can be eliminated and drug-related risk behaviors, such as needle-sharing and unsafe sexual practices, can be reduced significantly, thus decreasing the risk of exposure to HIV and other infectious diseases. Therefore, drug abuse treatment is HIV prevention.

What treatments are effective for methamphetamine abusers?


At this time, the most effective treatments for methamphetamine addiction are behavioral therapies such as cognitive behavioral and contingency management interventions.

For example, the Matrix Model, a comprehensive behavioral treatment approach that combines behavioral therapy, family education, individual counseling, 12-Step support, drug testing, and encouragement for nondrug-related activities, has been shown to be effective in reducing methamphetamine abuse. Contingency management interventions, which provide tangible incentives in exchange for engaging in treatment and maintaining abstinence, have also been shown to be effective.

There are currently no specific medications that counteract the effects of methamphetamine or that prolong abstinence from and reduce the abuse of methamphetamine by an individual addicted to the drug.

However, there are a number of medications that are FDA-approved for other illnesses that might also be useful in treating methamphetamine addiction.

Recent study findings reveal that bupropion, the anti-depressant marketed as Wellbutrin, reduced the methamphetamine-induced "high" as well as drug cravings elicited by drug-related cues.

This medication and others are currently in clinical trials, while new compounds are being developed and studied in preclinical models.

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