Although these pleasure centers can heal over time, research suggests that damage to users' cognitive abilities may be permanent such as severe impairment in memory, judgment and motor coordination, similar to symptoms seen in individuals suffering from Parkinson's Disease.
Changes in brain chemistry can lead to disturbing, even violent behavior.
“For example, in lab experiments done on animals, sex causes dopamine levels to jump from 100 to 200 units, and cocaine causes them to spike to 350 units. "[With] methamphetamine you get a release from the base level to about 1,250 units, something that's about 12 times as much of a release of dopamine as you get from food and sex and other pleasurable activities," Rawson says. "This really doesn't occur from any normally rewarding activity. That's one of the reasons why people, when they take methamphetamine, report having this euphoric [feeling] that's unlike anything they've ever experienced." Then, when the drug wears off, users experience profound depression and feel the need to keep taking the drug to avoid the crash.”
Meth abuse causes the destruction of tissues and blood vessels, inhibiting the body's ability to repair itself.