Addiction is a brain disease. This is undeniably a bold and controversial statement and one which usually elicits varied reactions ranging from denial and skepticism to wholehearted agreement. The lack of consensus means that when Canada’s “neuroscientist in chief” is defending this view, people to sit up and pay close attention. During his recent talk as part of our “Neuroethics of Addiction” workshop, Dr. Anthony Phillips, the newly appointed scientific director of the Canadian Institutes for Health Research’s (CIHR) Institute for Neuroscience, Mental Health and Addiction (INMHA), explored how the brain networks and chemistry change as a result of repeated drug abuse. Dr. Phillips explained that people who abuse drugs are in the process of changing their brain chemistry (mainly through fluctuations in dopamine levels), which has semi permanent effects on decision-making processes.
From the data Dr. Phillips presented, it is clear that the brain plays a role in addiction. The ‘reward network’ and dopamine-glutamate system function pathologically such that basic needs such as food are ignored and seeking a particular drug is prioritized. But is addiction only a brain disease? I think it would be shortsighted to conceptualize the condition in that way. In addition to brain activity, socioeconomic, psychological and political factors, among others contribute to onset of the addictive behavior as well as to the disease course itself. This is not to say that investigating the neuroscience of addiction and addictive behavior is not a worthy endeavor. After all, Dr. Phillips expressed hope that research on the neuroplasticity (the brain’s ability to change itself) may have important implications for treatment of addiction. The contributions that science can make towards understanding and managing addiction are undoubtedly valuable. It is important, however, to acknowledge the complexity of the condition and avoid reductionist perspectives on addiction.
Neuroethics at the Core 
Some addictions, or some cases of addictive behavior patterns, at certain stages, are brain diseases or neurological disorders, but others are not. Much depends upon what best explains the behavior (reference to neurobiology/neurochemistry alone or not). Much also depends, similarly, on the forms and limits of voluntary control that an addicted agent may have over his or her behavior, in certain settings and circumstances. I like to put all this by saying that some addictions are not diseases or disorders of the brain even though or if all addictions are based, ultimately, in the brain.
The position outlined above is defended in chapter of a book that I have just written for Routledge and which is entitled THE DISORDERED MIND. The book is scheduled to appear later this year.
From a neuroethical point of view, it is important to be clear about whether this, that, or another feature of addictive behavior is, in certain circumstances or settings, under some degree of voluntary control. Much that many addicted agents do, with respect to their addictions, is voluntary; is the product of decision and deliberation; is governed by their own (as it may be called) cognitive/motivational dynamics; and is not, in the classical sense of this term, compulsive. For analyses of the responsibility of persons for (some forms of) addiction, a book that I am editing for The MIT Press with RISD’s/Brown’s Jeffrey Poland and which is entitled ADDICTION AND RESPONSIBILITY, and which also will appear later this year, offers a sample of original papers on the topic.
I am not a Natural Born Blogger. (This is only the second or third time I have offered a comment in any blog.) And I do appreciate that citing books is not a detailed way to move a blog-along. However I think it important not to yield to the following temptation in the field of neuroethics. (And this is why I make the brief comments above.) Namely: to take a form of human behavior, even one that is unhealthy and imprudent, and to assume that just because neural activity is its base, the behavior itself is best understood in neuroscientific and somehow therein personal agency-denying terms. The temptation here is not such much reduction (all scientific explanation is, in some sense, reductive), but one of (what may be called) misbegotten agentic bypassing; bypassing reference to cognition and motivation in the effort to best account for the behavior. A explanatory ‘bypass’ is required when the illnesses is, say, a cardiovascular accident or advanced Alzheimer’s, but not necessarily in each and every case of addiction.
George – I don’t think that defining addiction as a brain disease presupposes that the behaviour is involuntary – rather, that the response is abnormal, and this abnormality is contingent upon a change in the underlying neurochemistry of the brain. Nor does addiction as brain disease suggest that agency is bypassed, but that it is compromised.
I would agree that not all forms of what is termed ‘addiction’ may represent disease per se (however that is defined), but at least for the most severe forms of addiction – heroin addiction, for example – it seems clear that there is a change in neurochemistry, and, most importantly, that the behavioural change can be reasonably (if imperfectly) explained by the underlying change in neurochemistry.
I look forward to reading your chapter in the book.
Hi Peter (if I may)
Thanks for your response.
There is, as you know, a huge literature on what makes a disease a disease. Reference to abnormality as such, whatever that may mean (statistical?) is of little use in capturing the very idea of diseases qua diseases. I do think that reference to a condition’s being involuntary is part, however, though also only a part, of a condition’s disease status. Think of Alzheimer’s Dementia, for instance. This is not something that one brings on oneself by an act of will (personal decision) or ‘turn’s off’ sometimes when one wishes.
Of course one also has to distinguish between the proximal and distal sources of a disease, too, and between different types of diseases, those that, for example, are by nature chronic and pervasive and those that are episodic and only circumstantially impairing (and hence with different standards of personal manageability).
My concern at this point, however, in this blog only is the following. The point that the mere fact that a condition is brain based and, say, unhealthy does not mean that it is a neural disease (or disorder). That point, I believe, applies not just to various forms of addiction (not all, as you aptly point out), but to a wide range of brain based ailments.
Nice post. To me, and with what I’ve seen and experienced first hand, addiction may begin as a brain or neurological condition, but obviously when dealing with drugs that cause severe withdrawls, the addiction passes that first stage of mental addiction when it turns into a physical need.
In any event, addiction should be treated as a serious lifelong disease. A complete lifestyle change is necessary.
Robin Hale