Science, Science and Tech

The science behind addiction

Addiction is defined as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences. The use of the term “brain disease” may sound out of place when used in the context of substance abuse, but even short to medium term drug abuse can change the brain structure and how it works.

In general, most individuals take drugs for the following reasons, and you can see for yourself from Concrete’s Drugs and Alcohol Survey results that those who responded share similar views.

To feel good

Most drugs produce intense feelings of pleasure. This initial sensation of euphoria is followed by other effects, which differ with the type of drug used. For example, with stimulants such as cocaine, the “high” is followed by feelings of power, self-confidence, and increased energy. In contrast, the euphoria caused by opiates such as heroin is followed by feelings of relaxation and satisfaction.

To feel better

Some people who suffer from social anxiety, stress-related disorders, and depression begin using drugs in an attempt to lessen feelings of distress. Stress can play a major role in beginning drug use, continuing drug abuse, or relapse in patients recovering from addiction.

To do better

The increasing pressure that some individuals feel to chemically enhance or improve their athletic or cognitive performance can similarly play a role in initial experimentation and continued drug use.

Curiosity and “because others are doing it”

In this respect adolescents are particularly vulnerable because of the strong influence of peer pressure; they are more likely, for example, to engage in “thrilling” and “daring” behaviours.

Many drug abusers argue that it’s harmless fun and as long as they are still enjoying themselves then how much damage is being done? However, the initial effects that are perceived as being positive, can quickly escalate until users feel they need to take drugs simply to feel “normal”. Consider also how a social drinker can become intoxicated whilst having fun, but can then put themself behind a wheel and quickly turn a pleasurable activity into a tragedy for them and others. It is no longer harmless fun.

But how exactly do drugs affect the brain?

One of the key areas of the brain to look at when considering substance abuse is that of the limbic system. This is the area of the brain that is responsible for controlling the “reward circuit” and regulates our ability to feel pleasure. Pleasure is very important in everyday life as it means we continue to do things that are essential to our survival, such as eating. This system is also responsible for our perception of the emotions we are feeling, which explains the mood altering properties of many drugs. Most drugs achieve this by flooding the reward circuit with dopamine, the same chemical that is used to reward humans after sex, eating and exercise.

Drugs are chemicals and they work in the brain by tapping into the brain’s communication system and interfering with the way nerve cells normally send, receive, and process information. Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter. This similarity in structure “fools” receptors and allows the drugs to lock onto and activate the nerve cells. Although these drugs mimic brain chemicals, they don’t activate nerve cells in the same way as a natural neurotransmitter, and they lead to abnormal messages being transmitted through the network.

Other drugs, such as amphetamine or cocaine, can cause the nerve cells to release abnormally large amounts of natural neurotransmitters or prevent the normal recycling of these brain chemicals. This disruption produces a greatly amplified message, ultimately disrupting communication channels. The difference in effect can be described as the difference between someone whispering into your ear and someone shouting into a microphone.


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