Tolerance, Dependence, and WithdrawalAs with most long-term drug consumption, users tend to develop a tolerance to the meth, requiring higher and higher dosages to experience the desired effects. This condition occurs because of the brain’s tendency to reduce the impact of a psychoactive substance in response to repeated exposure. Tolerance increases the risk of overdose and further intensifies an addiction. Also, over time, users can become dependent on meth, meaning that the brain has become so accustomed to the drug’s presence that it can no longer function properly without it. This condition results in highly unpleasant withdrawal symptoms when the user attempts to quit or cut back, including depression, anxiety, irritability, fatigue, and intense cravings. Research has revealed that long-term meth users’ brains are altered to the point that they find it difficult to experience pleasure other than that produced by the drug, which encourages further drug abuse. Chronic methamphetamine abusers may also experience symptoms such as the following:
- Mood swings
- Violent outbursts
Psychotic EffectsExcessive meth use can also produce psychotic features that include paranoia and delusions, as well as visual, auditory, and tactile hallucinations. For example, some chronic meth abusers report the feeling of insects crawling under their skin. Unfortunately, some of these psychotic features can continue for months or years after the user stops taking meth. In fact, recurrence of these symptoms can be triggered by stressful situations long after the person has discontinued use.
Emotion and MemoryNeuroimaging research has found that meth abuse significantly interferes with dopaminergic activity, leading to reduced motor function and impaired verbal learning. Others studies have shown that meth users exhibit severe damage in the region of the brain linked to memory and emotion. Meth abuse can also adversely impact brain cells known as microglia, which support the brain by eliminating damaged neurons and defending against infections. However, excessive microglial activity in the brain can damage healthy neurons. Imaging studies have revealed that the brains of former meth abusers have double the quantity of microglial cells compared to people who were never exposed to meth.
Some Long-Term Effects of Meth are IrreversibleStudies have also shown that some of the brain damage induced by chronic meth abuse is partly reversible. Motor and verbal memory have shown some improvement after prolonged abstinence from meth – but this reversal may take more than a year. One study, however, revealed that other brain functions damaged by meth use did not recover even after 14 months, and other research has found that meth use increases the risk of stroke and leads a higher incidence of Parkinson’s disease – conditions that are irreversible. There are other physical effects that meth users can encounter including severe weight loss, skin sores and rampant tooth decay, tooth loss, and gum disease, a condition also known as “meth mouth.”
Other DamageChronic users can also experience an overall increase in heart rate and blood pressure, and arrhythmia – an irregular heartbeat that can result in cardiovascular collapse or death, as well as liver, kidney and lung damage. Other irreversible long-term effects of meth include the following:
- Irreparable damage to blood vessels in the brain and heart
- Deterioration of tissues in the nasal cavity if snorted
- Respiratory problems if smoked
- Infections and abscesses if injected
- Damage to the brain similar to Alzheimer’s disease