One of the negative consequences of long-time meth abuse is developing an addiction to the drug. Methamphetamine addicts will continue compulsive drug seeking and drug use in spite of negative consequences. This is due to changes in the brain that changes the user's reward system.
Tolerance and WithdrawalAs with other drug addictions, meth addicts develop a tolerance to the drug, requiring higher dosages to get the same effect, and they experience withdrawal symptoms if they try to quit.
National Institute on Drug Abuse research has shown that long-term meth abusers' brains are changed to the point that they may find it difficult to experience any pleasure other than that provided by the drug. This provokes even further drug abuse.
When methamphetamine addicts try to quit, withdrawal symptoms can include:
- Intense craving
Other Psychiatric SymptomsChronic methamphetamine abusers can also experience other symptoms, including:
Psychotic FeaturesMeth abuse can also produce a variety of psychotic features that can include paranoia, visual and auditory hallucinations, and delusions. Some chronic methamphetamine abusers report the sensation of insects creeping under the skin.
Unfortunately, some of these psychotic symptoms can persist for months or years after the abuser quits using meth. Reoccurrence of these symptoms can be triggered by stress long after the person has stopped using.
Emotion and MemoryNIDA-sponsored neuroimaging studies have found that meth use alters the dopamine system associated with reduced motor speed and impaired verbal learning. Others studies have found that meth abusers show severe damage in the region of the brain associated with emotion and memory.
Methamphetamine abuse can also negatively affect non-neural brain cells called microglia, which support the brain by removing damaged neurons and defending the brain against infectious agents. But, too much microglial activity can damage healthy neurons in the brain.
Imaging studies have detected double the levels of microglial cells in the brains of former methamphetamine abusers, compared with people who never used meth.
Some Reversible, Some NotSome studies have found that some of the brain damage caused by chronic methamphetamine abuse is partially reversible. Motor and verbal memory have shown to improve after extended abstinence from methamphetamine (14 months, but not six months).
However, other brain functions damaged by meth abuse did not recover even after 14 months, one study found.
Other studies have discovered that methamphetamine use increases the risk of stroke and can lead to a higher incidence of Parkinson's disease. These conditions are irreversible.
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National Institute on Drug Abuse. "Methamphetamine." Research Report Series Updated September 2013
The Partnership at DrugFree.org. "Methamphetamine." Drug Guide. Accessed March 2014.