A famous experiment studied the effect of methamphetamine use on lab animals, who were given a dose of methamphetamine every time they pushed a lever. In spite of the fact that food and water bowls were within easy reach, these lab animals ignored eating and drinking, ultimately dying of starvation. (Sanello: 32)
Why is it used?
As with many other drugs including cocaine, methamphetamine works by releasing large amounts of dopamine into the section of the brain that controls the feeling of pleasure. In fact, it is suggested that methamphetamine produces the equivalent of 600 times the normal amount of dopamine normally released by the brain during pleasurable events. (Sanello: 32) The effects of meth, which include increased activity, decreased appetite, and a general sense of well-being, can last up to 12 hours and users often engage in a "binge and crash" pattern where they will continue to use the drug for days, "sketching" or "tweaking" until they "crash". (Sanello: 33)
In addition to the pleasurable effects users may experience, methamphetamine has a number of other short-term effects and even a single high dose of the drug has been shown to damage nerve terminals in the dopamine-containing regions of the brain. Meth also effectively shuts down your brain's sleep, hunger, and thirst centers. (Sanello: 31) Dehydration, in addition to increased respiration and elevated body temperatures (sometimes to lethal levels) may also result. Other side effects can include irritability, confusion, nervousness, nonstop talking, tremors, convulsions, anxiety, paranoia, and aggressiveness. (Sanello: 38)
Less serious side effects can also include pupil dilation, dizziness, teeth grinding, impaired speech, dry or itchy skin, acne, numbness, and sweating. (Sanello: 38)
"Chasing the Dragon"
As with other addictive drugs, chronic use of methamphetamine can cause a tolerance to develop within the user. As the user "crashes" they can become anxious and depressed, and may continue to use increasing amounts of the drug in search of the original rush. (Sanello: 34)
Methamphetamine use can result in rapid heart rate, irregular heartbeat, increased blood pressure, and irreversible blood vessel damage that may result in stroke. Chronic users may also suffer from inflammation of the heart lining. (NIDA: 5)
Users who inject methamphetamine may damage their blood vessels, in addition to causing skin abscesses known as "speed bumps" by accidentally injecting the drug under the skin. (Sanello: 38)
Continued methamphetamine use can damage the brain's ability to produce dopamine. Chronic use may also result in violent behavior, anxiety, confusion, and insomnia. Psychotic features including paranoia, auditory hallucinations, mood disturbances, delusions, and homicidal/suicidal thoughts. These behaviors can even persist after the drug use has ceased, sometimes for months or even years afterwards. (Sanello: 55)
Methamphetamine has been known to cause premature osteoporosis, whereby teeth and bones become more brittle and prone to breaking. (Sanello: 43)
Though research indicates that methamphetamine can often have the effect of increasing the libido in users, long-term use may also be associated with decreased sexual functioning in men. (NIDA: 6)
One side effect of long-term use is the delusion that one's skin is infested with insects. (Sanello: 66) The feeling that these "crank bugs" are crawling under their skin will cause users to scratch their skin sometimes to the point of developing sores. (Lloyd: 1)