How Does Addiction Affect the Brain?

The Link Between Dopamine and Addiction

The effect of substance abuse or addictive behaviours on the brain is truly a complex issue.

Neurons (nerve cells) are responsible for the sending and receiving of neurotransmitters (chemical messengers) to other neurons. Dopamine is a neurotransmitter, and our bodies naturally produce this. Our bodies are responsible for maintaining a bio-chemical balance (equilibrium) of dopamine and other chemicals.

The brain consists of several dopamine pathways, which are commonly known as reward systems. Most types of reward increase the amount of dopamine in the brain. For example: When people eat, or sleep, they generally feel good. Dopamine also influences movement, memory, cognition, attention, sleep, mood and learning.

Substances and pleasurable behaviours increase dopamine in the brain. When we introduce substances to the body, the bio-chemical balance is thrown off, and different lobes in the brain are affected. In other words, movement, memory, cognition, attention, sleep, mood and learning are altered. The system becomes flooded with dopamine. The substance causes us to feel high and euphoric. It also allows us to feel pleasure. We learn to make associations with the things that make us feel good, and as a result, we are likely to continuing doing (or do more) of what makes us feel good.

This helps to explain why pleasurable activities such as winning (or believing you may win) at a casino or engaging in sexual activity can become addictions in themselves. When substances are added to the mix they also affect other neurotransmitters in the brain aside from dopamine.

These other neurotransmitters are responsible for some of the individual physical effects of substances on the brain and body. However, dopamine is either directly or indirectly involved in all addiction.

Sources: cmah.ca and drugabuse.gov