Drug Abuse and Addiction
Many people do not understand why individuals become addicted to drugs or how
drugs change the brain to foster compulsive drug abuse. They mistakenly view
drug abuse and addiction as strictly a social problem and may characterize those
who take drugs as morally weak. One very common belief is that drug abusers
should be able to just stop taking drugs if they are only willing to change
their behavior. What people often underestimate is the complexity of drug
addiction—that it is a disease that impacts the brain and because of that,
stopping drug abuse is not simply a matter of willpower. Through scientific
advances we now know much more about how exactly drugs work in the brain, and we
also know that drug addiction can be successfully treated to help people stop
abusing drugs and resume their productive lives.
What is drug addiction?
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.
What happens to your brain when you take drugs?
Drugs are chemicals that tap
into the brain's communication system and disrupt the way nerve cells normally
send, receive, and process information. There are at least two ways that drugs
are able to do this: (1) by imitating the brain's natural chemical messengers,
and/or (2) by overstimulating the "reward circuit" of the brain.
Some drugs, such as marijuana and heroin, have a similar structure to
chemical messengers, called neurotransmitters, which are naturally produced by
the brain. Because of this similarity, these drugs are able to "fool" the
brain's receptors and activate nerve cells to send abnormal messages.
Other drugs, such as cocaine or methamphetamine, can cause the nerve cells to
release abnormally large amounts of natural neurotransmitters, or prevent the
normal recycling of these brain chemicals, which is needed to shut off the
signal between neurons. This disruption produces a greatly amplified message
that ultimately disrupts normal communication patterns.
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 abusing drugs.
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.
Next: Why do some people become addicted, while others do not? »
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