What are the long-term effects
of methamphetamine abuse?
Long-term methamphetamine abuse results in many damaging effects,
including addiction. Addiction is a chronic, relapsing disease,
characterized by compulsive drug-seeking and drug use which is accompanied
by functional and molecular changes in the brain. In addition to
being addicted to methamphetamine, chronic methamphetamine abusers
exhibit symptoms that can include violent behavior, anxiety, confusion,
and insomnia. They also can display a number of psychotic features,
including paranoia, auditory hallucinations, mood disturbances,
and delusions (for example, the sensation of insects creeping on
the skin, called "formication"). The paranoia can result
in homicidal as well as suicidal thoughts.
With chronic use, tolerance for methamphetamine can develop. In
an effort to intensify the desired effects, users may take higher
doses of the drug, take it more frequently, or change their method
of drug intake. In some cases, abusers forego food and sleep while
indulging in a form of binging known as a "run," injecting
as much as a gram of the drug every 2 to 3 hours over several days
until the user runs out of the drug or is too disorganized to continue.
Chronic abuse can lead to psychotic behavior, characterized by intense
paranoia, visual and auditory hallucinations, and out-of-control
rages that can be coupled with extremely violent behavior.
Although there are no physical manifestations of a withdrawal syndrome
when methamphetamine use is stopped, there are several symptoms
that occur when a chronic user stops taking the drug. These include
depression, anxiety, fatigue, paranoia, aggression, and an intense
craving for the drug.
In scientific studies examining the consequences of long-term methamphetamine
exposure in animals, concern has arisen over its toxic effects on
the brain. Researchers have reported that as much as 50 percent
of the dopamine-producing cells in the brain can be damaged after
prolonged exposure to relatively low levels of methamphetamine.
Researchers also have found that serotonin-containing nerve cells
may be damaged even more extensively. Whether this toxicity is related
to the psychosis seen in some long-term methamphetamine abusers
is still an open question.
Source: National Institute on Drug Abuse
NIH Publication Number 97-3859