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Addiction: How Does it Affect the Brain?

A person who has an addiction will suffer three main symptoms: intense feelings of need or desire for the object of the addiction (cravings), an inability to control their use of it, and persistence in using it despite negative consequences. A person can become addicted to substances, like drugs and alcohol, and to activities, like gambling or social media use. If you have an addiction, your brain is literally different from those who do not have one. Addictions cause a change in the chemistry of the brain, changing how it perceives pleasurable sensations. As a result, breaking out of an addiction is difficult, but it is by no means impossible. If you are looking for drug addiction therapy then please see here.

A Look Into Addiction

Addiction is a surprisingly common mental issue; it can happen to people of very different backgrounds indiscriminately. Of course, almost nobody sets out to become addicted to a substance or activity, but it can happen to anyone. For one example, consider the United States; nearly one out of every ten Americans (23 million) is addicted to some kind of substance. 70% of those are alcoholics while the other 30% are addicted to drugs, the most common of which are marijuana, narcotics, and cocaine.

How Addiction Affects Pleasure

In the human brain, pleasure is always handled the same way. It starts in the pleasure centre of the brain, an area of the brain known as the nucleus accumbens. It is found just under the cerebral cortex. When a pleasurable activity occurs, be it a high-calorie meal, sexual activity, or drug use, the nucleus accumbens releases a neurotransmitter called dopamine, which reacts with other cells in the brain to cause good feelings. Addictive drugs and activities cause a strong release of this neurotransmitter and therefore result in powerful feelings of pleasure. When combined with another activity that already causes pleasurable feelings, the addictive response is even stronger and develops even faster, because dopamine is released in larger quantities and with more reliability than with the object of the addiction alone.

Memory and Addiction

Scientists used to believe that the experience of pleasure and the corruption of that mechanism in addicts was enough by itself to cause addicts to struggle to break their addiction. But recent studies suggest that addiction and the reasons behind it are much more complex. As an example, research has shown that in addition to causing pleasurable feelings, dopamine also has an important role in memory production and in learning. The interaction between the elevated levels of dopamine and another neurotransmitter, glutamate, essentially takes over the brain’s reward system, which helps it to learn what keeps a person alive. This system connects behaviours that sustain the individual and the species, such as mating and eating, with feelings of happiness. In the case of addiction, the brain instead learns to connect the addictive substance with those same feelings; the brain is acting as if it needs that substance to survive.

The brain also stores the environmental stimuli associated with the use of the addictive substance or the addictive activity. The brain is doing this so it can find the substance again; remember, the brain “believes” it needs this substance for basic survival. This learning process acts as both a driver for addiction and as a cause for relapses after a period of sobriety. An addict (or former addict) will encounter a stimulus that is associated with the addiction, and experience cravings. This could be a hypodermic needle for an intravenous drug user or a bottle of gin for the alcoholic, as well as people or behaviours that were typically encountered in combination with the use of the addictive substance.


Outside of addiction, the brain’s reward system generally only activates after time and effort have been expended (in gathering food or finding a mate). This means that the reward system can continue to provide neurotransmitters in the same amounts regardless of what activated the system. However, with addicts, the brain starts to adapt to the object of the addiction, meaning that the substance or activity becomes less enjoyable at the same doses. More and more of the addictive substance is needed to get the same result. This happens because addictive behaviours flood the brain with neurotransmitters in a way that natural stimuli do not.

This overwhelming amount of neurotransmitters can result in the addict becoming confused or unable to “think straight”. Normal drivers of behaviour, even base ones like the need to obtain food, are basically no longer affecting the individual. The compulsion to obtain more of the addictive substance takes over in place of normal behaviour. ​


Scientists’ and doctors’ understanding of addiction is changing as more research is done. This continued research into a difficult topic will hopefully result in new and better treatments for this horrid mental illness.