Addiction is a chronic, often relapsing brain disease that causes
compulsive drug seeking and use despite harmful consequences to the
individual that is addicted and to those around them.
Drug addiction is
a brain disease because the abuse of drugs
leads to changes in the structure and function of the brain. Although
it is true that for most people the initial decision to take drugs is
voluntary, over time the changes in the brain caused by repeated drug
abuse can affect a person?s self control and ability to make sound
decisions, and at the same time send intense impulses to take drugs.
It is because of these changes in the brain that it is so challenging
for a person who is addicted to stop abusing drugs. Fortunately, there
are treatments that help people to counteract addiction?s powerful
disruptive effects and regain control. Research shows that combining
addiction treatment medications, if available, with behavioral therapy
is the best way to ensure success for most patients. Treatment
approaches that are tailored to each patient?s drug abuse patterns and
any co-occurring medical, psychiatric, and social problems can lead to
sustained recovery and a life without drug abuse.
Similar to other chronic, relapsing
diseases, such as diabetes, asthma, or heart disease, drug addiction
can be managed successfully. And, as with other chronic diseases, it is
not uncommon for a person to relapse and begin abusing drugs again.
Relapse, however, does not signal failure?rather, it indicates that
treatment should be reinstated, adjusted, or that alternate treatment
is needed to help the individual regain control and recover.
Nearly all drugs, directly or indirectly, target the brain?s reward
system by flooding the circuit with dopamine. Dopamine is a
neurotransmitter present in regions of the brain that control movement,
emotion, motivation, and feelings of pleasure. The overstimulation of
this system, which normally responds to natural behaviors that are
linked to survival (eating, spending time with loved ones, etc),
produces euphoric effects in response to the drugs. This reaction sets
in motion a pattern that ?teaches? people to repeat the behavior of
As a person continues to abuse drugs, the brain adapts to the
overwhelming surges in dopamine by producing less dopamine or by
reducing the number of dopamine receptors in the reward circuit. As a
result, dopamine?s impact on the reward circuit is lessened, reducing
the abuser?s ability to enjoy the drugs and the things that previously
brought pleasure. This decrease compels those addicted to drugs to keep
abusing drugs in order to attempt to bring their dopamine function back
to normal. And, they may now require larger amounts of the drug than
they first did to achieve the dopamine high?an effect known as tolerance.
Long-term abuse causes changes in other brain chemical systems and
circuits as well. Glutamate is a neurotransmitter that influences the
reward circuit and the ability to learn. When the optimal concentration
of glutamate is altered by drug abuse, the brain attempts to
compensate, which can impair cognitive function. Drugs of abuse
facilitate nonconscious (conditioned) learning, which leads the user to
experience uncontrollable cravings when they see a place or person they
associate with the drug experience, even when the drug itself is not
available. Brain imaging studies of drug-addicted individuals show
changes in areas of the brain that are critical to judgment,
decisionmaking, learning and memory, and behavior control. Together,
these changes can drive an abuser to seek out and take drugs
compulsively despite adverse consequences?in other words, to become
addicted to drugs.
Source: The National Institute on Drug Abuse (NIDA)