Neuroscience of Addiction

This is the fourth in a series of blogs contributed by our PM clinician Gregory Rennie, who will introduce you to various aspects of addiction and its treatment using psychotherapy.  Gregory provides access to collaborative care with PM psychiatrists via the Psychotherapy Matters Virtual Clinic (PMVC) for his clients.

Today, we know that addiction or chemical dependence is a disease of the brain.  It is more accurately known as substance use disorder according to the Diagnostic and Statistical Manual of Mental Disorders 5 (1). Much progress over the past decade has led to increased acceptance for the fact that substance use disorder is an illness affecting the brain like asthma is an illness affecting the lungs. However, sufferers of addiction continue to face discrimination and stigma.

In 1784, Dr. Benjamin Rush, an American physician, made the counterintuitive statement about addiction: “this condition is a disease that physicians should be treating” in his book entitled “Inquiry into the Effects of Ardent Spirits on the Human Mind and Body”(2).  In 2011, the American Society of Addiction Medicine (ASAM) redefined chemical dependence as “a primary, chronic disease of brain reward, motivation, memory and related circuitry. Dysfunction in these circuits leads to characteristic biological, psychological, social and spiritual manifestations. This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors” (3).

Through the technological advancement in brain scans we now see what is behind this potentially deadly disease.  It is not a lack of character, bad morals or bad choices but a brain that has been hijacked.  The person becomes powerless over their drug of choice.

Neuroscience is helping us to understand more about chemical dependency than ever before. In his 2007 book The Science of Addiction: From Neurobiology to Treatment  Dr. Carlton K. Erickson, a researcher and professor of pharmacology at the University of Texas noted “It is most helpful for recovering people and those who treat them to fully understand that powerlessness is not a mental or moral weakness, but rather a disease involving brain chemistry and in most cases a genetic vulnerability”(4) .

Unfortunately, in early recovery, relapse is common. It is known that the disease is most active when the person quits.  Relapse is a return to past behavior that results in using their drug of choice again. This could happen a few weeks, months or years after the person has abstained. The use of alcohol, cocaine, opiates or gambling is always preceded by behaviour that is often oblivious to the individual.

A trained and experienced therapist can help the person become aware of their behaviour. Addiction counselling is successful in providing the person tools and awareness to act on changes in behavior.  Relapses can be prevented. It often takes professional intervention.

Support after quitting or completing treatment is often minimized and overlooked by the individual. A 28 day program in a treatment centre (rehab) often is not enough. The person needs to know that treatment is not recovery. Recovery is a lifelong process.

Many people believe when they have quit using drugs, they don’t need further help. Early recovery can be freeing and even euphoric. Confidence runs high. Unfortunately, issues float to the surface that can lead to using their “solution” to escape, to numb or to feel good. Often times, the person needs further help to find out what the “problem” is. Without ongoing support, old behaviours can return. Relapse prevention is a learned skill. To be proficient, the person needs to learn how to use and practice these skills.

In relapse behavior, there is a functional disconnect between two parts of the hijacked brain, the limbic system and the frontal cortex that assists us in decision-making and whether to act on a reward. It is described by Dr. Anna Rose Childress, a psychology researcher at the University of Pennsylvania, as the “go” and “stop” system. She described it “as though [the systems] have become functionally disconnected. It is as though the ‘go’ system is sort of running off on its own, is a rogue system now, and is not interacting in a regular, seamless, integrated way with the ‘stop’ system”(5). 

In their first two years of abstinence, the person is biologically vulnerable to the “go” system. Their brain is slowly restructuring during this period. They are bombarded daily by cues and associations that could lead to the activation of the disease and relapse. Unfortunately, this does not occur on a conscious level but a biological one.

The good news, is that with diligent work, successful recovery is attainable and is observed by psychiatrists, physicians and addiction counsellors every day. In “From Treatment to Sustained Recovery,” William White stated “There are millions of individuals and their families in long-term recovery from the effects of severe substance use problems. Recovering people can go on to lead lives of significant achievement and community service”(6).

Through current research, we are discovering new medications that may help with craving and withdrawal symptoms and the results are promising. Not unlike the recommendations for clinical depression, a combination of medication and counselling would be more effective than either method alone.

For those struggling with a substance use disorder, knowledge that their alcohol or drug “problem” is in fact a brain disease is enlightening and encourages them to continue seeking support in early recovery.

It is through imaging technology such as fMRI, PET and SPECT scans that we now can see what is going on inside the brain of an alcoholic and addict. We are living in a time of technological change that will provide improved insight into the mystery of the behaviour of an alcoholic, addict or problem gambler.

For more information, I strongly recommend the following resources:

  1. Centre for Addiction and Mental Health in Toronto, Ontario at
  2. National Institute on Drug Abuse in the USA at

In my experience, it is possible to recover from the impact of chemical dependence/abuse or substance use disorder.


1.     American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.

2.     Smith, David E. (2011). The Evolution of Addiction Medicine as a Medical Specialty. AMA Journal of Ethics, 13(12): 900-905. Retreived from:

3.     American Society of Addiction Medicine, April 2011, Retrieved from:

4.     Erickson, C.K. (2007). The Science of Addiction: From Neurobiology to Treatment. New York, NY: W.W. Norton & Company Inc, ISBN 978-0-393-70463-1

5.     Childress, A.R. (2007). From treatment to sustained recovery. Retrieved from:

6.     White, W. (2007). From treatment to sustained recovery. Retrieved from:



The views expressed in these blogs are the author’s own and not necessarily reflective of those of Psychotherapy Matters.  Information provided here and anywhere else on is for learning purposes only and should not be used to guide treatment of clients/patients. Copyright © 2016

Gregory Rennie
Gregory Rennie

Gregory Rennie has been an addiction therapist since 2005 and has also worked at agencies in Southern Ontario as an addiction therapist and concurrent disorders specialist.

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