The Science of Addiction and Mental Health


Addiction was always understood by scientists as our brains being like large circuit boards that passed information through electrical signals over a network, however recently research has changed our understanding of the brain.

Everyday living and cumulative life experiences cause changes in our thinking and affect general brain function

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Historically, scientists thought that our brains were like large circuit boards that passed information through electrical signals over a network. The messages told our bodies what to do and how to behave. Recently, research has changed our understanding of the brain. Researchers now look at how everyday living and our cumulative life experiences cause changes in our thinking and affect general brain functioning. We’re learning about what healthy brains look like through tools like brain imaging, brain stimulation, and genetics.

Through evolving research, we are getting a better picture of how stress changes our brains and makes us more vulnerable to brain diseases. Those on the forefront of research are now looking at how our brains react to social interactions and environmental influences. What they’re seeing is how all of these factors shape people’s experiences as they live with addiction and mental illness. The research is pointing to “true underlying causes” allowing scientists to “design precision treatments” addressing the unique and individual needs of many people.

Stress takes its toll

The effects that stress has on our brains and bodies are significant. It sets off reactions that flood our bodies with hormones and neurotransmitters that create exaggerated responses and affect our brain’s ability to self-regulate. Dr. Bessel Van Der Kolk is a psychiatrist who is well known for his research on Post-Traumatic Stress Disorder (PTSD). He talks about how we are hard-wired to stay safe. His studies show that people who have suffered compounded stress and trauma have a hard time relaxing the parts of their brains that monitors for danger. Instead, their threat response is always on. This state of constant activation means that the slightest occurrence can trigger intense over-activated reactions. Living in continuous fear makes it difficult to self-regulate and be able to return to a calm state where we are comfortable with ourselves. With addiction and mental illness, many people learn to “rely on external regulation — from medication, drugs like alcohol, constant reassurance, or compulsive compliance with the wishes of others.” That’s why broadening the scope of therapy and treatment is so critical. No single thing can be pinpointed as a sole cause for addiction and mental illness, and we continue to learn about the multiple influencing factors at play in cycles of addiction.

Neurobiology is helping develop better treatment

At its most basic level, our brains are motivated to do something that creates a reward that makes us feel good: in brain chemistry, that’s dopamine. In theory, we humans, with our big and complex brains, are supposed to be able to make decisions that chase the rewards and avoid punishments. It’s this belief that has created so much of the damaging stigma around addiction and mental illness: that people should be able to “just say no.”

Neuroscientists and clinicians are working together to understand how it’s much more complicated than mere behavioural modification. It has more to do with the way the brain reacts to stress and creates situations where negative emotions, environmental stimulants and learned associations with social situations take over. With addiction, responding to those influencers – smelling something, travelling past a place where someone purchased or used a substance – makes the brain want to return to that pleasurable state.

Recovery is about learning how to respond to those cravings so that the brain is still getting its reward. Instead of using a dangerous and addictive substance, it might mean re-training the brain to appreciate other, “sources of pleasure – say a good conversation with a friend or a beautiful sunset.” That’s also where pharmacological treatment can help, as part of a comprehensive treatment approach. Medications help “stabilize the craving brain while the planning and reasoning processes get back in shape.”

But medication isn’t the only way. There are newer approaches, such as Behavioural therapy which is another crucial part of treatment that needs to be part of a full treatment plan. It’s versatile because it can help individuals, groups and families understand how behavioural choices come into play as part of natural responses to stressors and affect relationships. Participants learn how to be aware of and then change behaviours to help regain control of their lives. For instance, Cognitive Behavioural Therapy (CBT) has been proven as an effective treatment for both addiction and mental illness when it’s combined with medication and other therapies. It helps people identify unproductive patterns of behaviour and thinking, then using those recognition skills to recognize vulnerabilities and redirect towards more productive, positive responses. There are many other therapies that leverage incentives, build positive approaches through community engagement, and encourage motivation through dialogue and reinforcement of positive behaviours. Combinations that include one or more of these techniques plus other treatments and therapies help keep people engaged and interested in recovery.

Are substance abuse issues and mental illness related?

While it’s not a matter of one causing the other or vice versa, there is strong evidence that linkages between the two are more common than people think. When they go undiagnosed, it can make things significantly worse. People often don’t want to believe that it’s possible to have both, however:

•About 50% of people with severe mental health disorders are affected by substance abuse.

•37% of alcohol abusers and 53% of drug abusers also have at least one serious mental illness.

•29% of people diagnosed with mental illness abuse either alcohol or drugs.

Instead, someone may self-medicate to relieve a mental health disorder and deal with difficult emotions, reduce stress and changes in their mood.

Substance use can also increase the risk of developing mental health disorders by inducing psychosis or accelerating and prolonging periods of depression. In effect, it can push someone who has been struggling over the edge. Drug interactions could mean that medications for mental illness could become less effective. The symptoms that were being treated could become worse or new ones could develop.

Symptoms and treatments are often different

When you're trying to understand whether there's a situation where substance abuse and mental illness are happening at the same time, you need to have patience. The symptoms aren't usually the same.

Someone with an addiction might have pretty clear thinking about their need to control their drinking or drug use. They could realize that they are going through prescription medication faster than expected. They might feel ashamed about their actions or have said something they regret. Or they might find that their relationships are strained because they are trying to hide their consumption.

Mental health problems could show up as depression, anxiety or mania without full awareness. Feeling helpless or hopeless; being restless, worried or on-edge; experiencing changes in energy levels, sleep, appetite or weight; having trouble concentrating, being extremely irritable, having racing thoughts and impaired judgement; and feeling nauseous, dizzy and tense can all be signs of more serious mental illness.

Treatment for addiction might include “detoxification, management of withdrawal symptoms, behavioural therapy and support groups,” while mental health therapy could focus on “medication, counselling, lifestyle changes and peer support.”

What to keep sight of in recovery

Knowing the kind of situations that make you feel uncomfortable or vulnerable is a significant first step to managing stress. It could mean avoiding places, people or even particular times of day that trigger feelings associated with drugs and alcohol. Look for ways to meet new people or try a new activity you’ve always been curious about.

Staying in touch with your support network is particularly helpful to be sure you feel well supported during recovery. Doctors, nurses, people in your group sessions, friends and family are all there to help you when you feel lonely, depressed or anxious. Talking with them could help when you think you have nowhere else to turn.

Remember the foundations of good physical and mental health:

•Get regular exercise

•Eat nutritious foods

•Practice mindfulness by focusing on the present

•Participate in activities that make you feel fulfilled

•Explore interests to learn new things

All of these will help you relieve stress and live well.


1.CAMH (n.d.), Understanding the Science of the Brain. Retrieved on July 30, 2019 from

2 Van der Kolk, B. Dr. (2015). The Body Keeps The Score: Brain, Mind, and Body in the Healing of Trauma. Viking Books.

3 Ibid.

4 Bierer, M. MD. (updated 2017, July 25). Is addiction a “brain disease”? Retrieved on July 30, 2019 from

5 Ibid.

6 Ibid.

7 Help Guide (n.d.) Reports published in the Journal of the American Medical Association as cited in Understanding the link between substance abuse and mental health. Retrieved on July 30, 2019 from

8 Ibid. 9 Ibid.