Tuesday, February 16, 2016

Addressing Criticisms of the Disease Model

Volkow, Koob, and McLellan on the neurobiology of addiction.

The New England Journal of Medicine recently published a review article, “Neurobiologic Advances from the Brain Disease Model of Addiction,” authored by three prominent figures in the field of addiction research: Nora Volkow, the director of the National Institute of Drug Abuse (NIDA); George Koob, the director of the National Institute of Alcohol Abuse and Alcoholism (NIAAA); and Thomas McLellan, founder and chairman of the Treatment Research Institute in Philadelphia.  The article summarizes the research that has “increasingly supported the view that addiction is a disease of the brain,” and concludes that “neuroscience continues to support the brain disease model of addiction.”

The implications of this, say the authors, are straightforward: “As is the case in other medical conditions in which voluntary, unhealthful behaviors contribute to disease progression (e.g., heart disease, diabetes, chronic pain, and lung cancer), evidence-based interventions aimed at prevention, along with appropriate health policies, are the most effective ways of changing outcomes.”

And some of the implications are immediate: “A more comprehensive understanding of the brain disease model of addiction many help to moderate some of the moral judgement attached to addictive behaviors and foster more scientific and public health-oriented approaches to prevention and treatment.”

In a supplementary appendix, the authors address some of the common criticisms of the disease model of addiction, and offer counter-arguments. The quotes below are excerpted directly from the appendix.

Most people with addiction recover without treatment, which is hard to reconcile with the concept of addiction as a chronic disease.

This reflects the fact that the severity of addiction varies, which is clinically significant for it will determine the type and intensity of the intervention. Individuals with a mild to moderate substance use disorder, which corresponds to the majority of cases, might benefit from a brief intervention or recover without treatment whereas most individuals with a severe disorder will require specialized treatment

—Addicted individuals respond to small financial rewards or incentives (contingency management), which is hard to reconcile with the notion that there is loss of control in addiction.

The demonstrated effectiveness of contingency management shows that financial cues and incentives can compete with drug cues and incentives – especially when those financial incentives are significant and relatively immediate; and when control has been simply eroded rather than lost. Contingency management is increasingly being utilized in the management of other medical disorders to incentivize behavioral changes (i.e., compliance with medications, diets, physical activity).

—Gene alleles associated with addiction only weakly predict risk for addiction, which is hard to reconcile with the importance of genetic vulnerabilities in the Brain Disease Model of Addiction.

This phenomenon is typical of complex medical diseases with high heritability rates for which risk alleles predict only a very small percentage of variance in contrast to a much greater influence of environmental factors (i.e., cirrhosis, diabetes, asthma, cardiovascular disease). This reflects, among other things, that the risk alleles mediate the response to the environment; in the case of addiction, the exposures to drugs and stressful environments.

Overlaps in brain abnormalities between people with addiction and control groups raises questions on the role that brain abnormalities have on addiction.

The overlap is likely to reflect the limitation of currently available brain imaging techniques (spatial and temporal resolutions, chemical sensitivity), our limited understanding of how the human brain works, the complexity of the neurobiological changes triggered by drugs and the heterogeneity of substance use disorders.

Treatment benefits associated with the Brain Disease Model of Addiction have not materialized.

Medications are among the most effective interventions for substance use disorders for which they are available (nicotine, alcohol and opiates). Moreover, progress in the approval of new medications for substance use disorders has been slowed by the reluctance of pharmaceutical companies to invest in drug development for addiction.

Benefits to policy have been minimal.

The Brain Disease Model of Addiction provided the basis for patients to be able to receive treatment for their addiction and for insurances to cover for it. This is a monumental advance in health policy. The Brain Disease Model of Addiction also provides key evidence-based science for retaining the drinking age at 21 years.


Robert said...

Thank you for this review of "Neurobiologic Advances from the Brain Disease Model of Addiction." It is heartening to see how far the addictions field has come in the last 50 years. That said, discussing "intercessions" rather than "interventions" may move the field even further along in its quest for efficacy.

Language is powerful; words affect results. "To intervene" is a "reactive” verb, more consistent with aggressive confrontation. "To intercede" is more consistent with brief motivational techniques and therefore a more "proactive verb." When practitioners "intervene," they attempt to do something to the individual thus facilitating what Miller refers to as "wrestling." When practitioners “intercede,” they insert themselves between the client and the SUD in order to facilitate increasing awareness on the part of the individual regarding the disorder. This facilitates movement through the stages of readiness to change, thereby resulting in more of a "dance" between the SUD individual and the practitioner.

I realize this sounds like semantics, but there is logic supporting this suggestion:

• To "intercede" is to act as a mediator whereas to "intervene" is to involve oneself in a situation to alter, hinder, if not stop an action’s continuance;
• The practitioner who intercedes mediates between the individual and the SUD itself...it is an experience indicative of enhancing self-awareness and discovery rather than a confrontation as a means of imposed awareness;
• The intent of Motivational Interviewing is to elicit from an individual personal insight that permits movement through the progressive stages of readiness to change until reaching the point of "taking action.” It is more about "drawing something unrealized out" from the individual rather than "forcing something external in";
• "Intervention" is what physicians do when employing the medical model; this may work wonders when detoxing or administering Naloxone, but "intercession" is what practitioners do when employing the behavioral health model that facilitates movement through the stages of readiness to change;
• Intervention is about doing something TO an individual and therefore is invasive, whereas intercession is about doing something WITH him or her in order to facilitate change.

Interventions pit practitioner against individuals with SUDs in a "tug-of-war" where for one to win, the other must lose. This is what Wm Miller (of Motivational Interviewing) meant by referring to it as "wrestling" with a client. Intercessions pursue a more collegial—although at times nonetheless blunt—relationship, one built on mutual trust and respect; what Miller meant when suggesting "dancing” with a client. As any accomplished ballroom dance team will report, "someone leads while the other follows," but the team does not win the competition until and unless "its members" enter a state of symbiosis. In essence, as the practitioner guides more than directs or leads in this dance, the partners, together, constitute an intercession in action. 

What do you think?

Robert J. Chapman, PhD

Dirk Hanson said...

I think your view of the semantics of addiction makes some sense. I've never been completely comfortable with the "intervention" terminology, either. It does have a suggestion of the coercive and the confrontational about it. "Intercession" carries some heavy connotations having to do with Western Christianity, but I definitely take your point, and love the image of practitioners "wrestling" with their clients.

Jason said...

Great post, Dirk.

I was going to post a block quote and a link, but it's hard to pull anything out.

Would you be open to me reposting the whole thing with attribution and a link?

Dirk Hanson said...

Sure, sounds great.

Shane Martin said...

Hello Dirk, I love your posts. Is there a way I could send you a private message? I just wanted to ask you something about your blog. If not I understand.

Dirk Hanson said...

info at dirkhanson.org

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