Long-Term Effects Prolonged use of amphetamines can lead to malnutrition and vitamin deficiencies, skin disorders, ulcers, lack of sleep, weight loss and depression. Frequent use of large amounts of amphetamines can cause brain damage that results in speech and thought disturbances. Users of large amount of amphetamines over a long period of time can develop an amphetamine psychosis, which is a mental disorder similar to paranoid schizophrenia. The psychosis is manifested by hallucinations, delusions, and paranoia. Bizarre, sometime violent, behavior is exhibited by those with amphetamine psychosis.
Symptoms usually disappear within a few weeks after drug use stops.
Amphetamines have the potential to produce tolerance, which means that increased amounts of the drug are needed to achieve the desired effects. Withdrawal symptoms can occur when use of amphetamines is stopped abruptly. The length and severity of the depression is related to how much and how often amphetamines were used. Since withdrawal from prolonged amphetamine use is accompanied by physical and mental depression, and usually not life threatening or physically painful symptoms, the majority of amphetamine users who want to stop can be treated by encouraging abstinence. In fact, users should avoid all stimulants, including caffeine and tobacco.