Dopamine is a neurotransmitter responsible for movement, pleasure, motivation, and cognitive processes, such as learning. For the purposes of understanding its role in addiction, let’s concentrate on pleasure and motivation.

Whenever we do something that propagates the advancement of our species, dopamine is released in order to motivate repetition of the action. When we sleep, eat, and have sex dopamine is released in our brain and the message is, “That was great, do it again!” We also release dopamine whenever we find something pleasurable. Be it 18th century poetry, heroin, or Radiohead, our brain will release dopamine to encode the stimulus as something that brings us pleasure.

Dopamine not only serves to categorize the good things we encounter in life, it also programs our pre-frontal cortex (the part of the brain involved in judgement and decision making) to alert us when the pleasurable stimulus is available. If your brain cells could talk, it might sound something like, “OMG! There’s a flyer on that lamppost for a Radiohead concert. Go look at it!” In other words, we become hyperaware of opportunities for engaging in behaviors that bring us pleasure. In fact, a study on people with alcoholism found they were more likely to spot alcoholic beverages in a busy photograph than people who don’t have problems with alcohol.

When we consume substances, it makes us feel good because our brains release dopamine, but drugs elicit a higher amount of dopamine release than is necessary. This is part of what causes experiences of euphoria and feeling high. Sometimes the amount of dopamine released is so great, the chemicals in our brain become unbalanced and we may experience hangover or withdrawal. In time, our brain regains chemical equilibrium. However, if one abuses substances, the brain may develop a tolerance (meaning the person needs to use greater amounts to get high) or dependence on the substance as a source of dopamine. If one becomes dependent on a drug, it may take some time for the brain to regain equilibrium and the person may experience extreme physical discomfort and emotional distress when they aren’t using. The period of re-calibration depends on the amount, type, and frequency of the drug used. It’s always a good idea to be under medical supervision and receive support from friends, family, and a mental health professional if you’re dependent on a drug and want to stop or decrease your use.

The mechanism of tolerance is also evident in impulse control disorders, such as sex addiction, kleptomania, and compulsive gambling. Although it doesn’t appear that persons with an impulse control disorder undergo the same intensity of withdrawal that persons addicted to substances experience, there can certainly be a period of re-calibration of dopamine receptors during which a person feels irritable and agitated after stopping a behavior.

Based on the information presented here, it appears that we are all hard-wired to become addicts and you may be asking yourself, “If this is true, why do some people become addicted and others don’t?” This is a really good question and the answer is “We don’t really know.” We can predict the likelihood of someone becoming an addict based on factors such as first age of substance use and family history of addiction, and we know that a lack of social support and coping strategies (especially when coupled with mental illness) can also lead to addiction, but there is no conclusive answer to date.

The best ways to prevent addiction are to educate yourself about the substances you use (or to abstain from substance use altogether) and to be mindful about the choices you make. If you have a mental illness, ensuring that you are getting appropriate treatment and maintaining social support are good preventative measures.