Posts tagged Diagnosis

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 these are able to do this: (1) by imitating the brain’s natural chemical messengers, and/or (2) by over stimulating 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 are able to “fool” the brain’s receptors and activate nerve cells to send abnormal messages.

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 behaviours that are linked to survival (eating, spending time with loved ones, etc), produces euphoric effects in response to these. This reaction sets in motion a pattern that “teaches” people to repeat the behaviour 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 these and the things that previously brought pleasure. This decrease compels those addicted to it to keep abusing it 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, decision-making, learning and memory, and behaviour control. Together, these changes can drive an abuser to seek out and take these compulsively despite adverse consequences—in other words, to become addicted to drugs.

Drug addiction is a preventable disease. Results from NIDA-funded research have shown that prevention programs that involve the family, schools, communities, and the media are effective in reducing drug abuse. Although many events and cultural factors affect drug abuse trends, when youths perceive drug abuse as harmful, they reduce their drug taking. It is necessary, therefore, to help youth and the general public to understand the risks of drug abuse and for teachers, parents, and healthcare professionals to keep sending the message that drug addiction can be prevented if a person never abuses drugs.