I just read an article (Grattan, et al. Depression and Prescirption Opioid Misuse Among Chronic Opioid Therapy Recipients with No History of Substance Abuse. Annals of Family Medicine 2012; 10(4):304-311) which purports to find that depression is a risk factor for misuse of opioids in those patients given them for pain control. There are a number of problems with the article, but most aren’t the fault of the authors. The article suffers from the times and paradigm we live in. The problems come down to definitions. The underlying paradigm of the article is that opioids can cause addiction, and that pre-existing substance abuse is a risk factor. The authors want to know, once they get rid of substance abuse, is depression still a risk factor.
The first problem is that no one actually screened these patients for addiction, only a history of substance abuse. If the patient had addiction and their most effective reward was sugar or gambling, this study would not have screened them out with the “substance abusers.”
The second problem is that the authors use the PHQ-8 to screen for “depression.” While this may not be a problem by itself, it’s clear that people reading this article are going to think that what the authors have found is an association between treatable Major Depression and opioid misuse. What the authors screened for was not the illness called Major Depression that has a treatment, but rather the symptoms of depression which can come from many causes, including pain.
If they had a neurobiological understanding of addiction they would have noticed that low dopamine in the midbrain is also a cause of many of the symptoms listed on the PHQ-8. So the screening device isn’t wrong; what’s wrong is the paradigm through which the answers are interpreted.
So rather than saying: “Some people have addiction and are so constructed as to get relief from the symptoms from opioids and those patients are at risk for unauthorized dose increase,” the authors say,”Clinicians should be alert to the risk of patients with depressive symptoms using opioids to relieve these symptoms and thereby using more opioids than prescribed.” The problem with this is that clinicians know only one way to aleviate depressive symptoms and that’s with anti-depressants. Currently there are 12 SSRIs and Wellbutrin as the most commonly used.
So if someone has a decreased endorphin response, let’s say because of a polymorphism of the mu receptor, they won’t release enough dopamine with normally rewarding activities. When they take an opioid they get energy because dopamine release returns to normal. The study suggests that these people have depressive symptoms which the average clinician will probably treat with an SSRI. Increased serotonin from the SSRI will, over time, actually decrease dopamine release and make the person worse. If they use Wellbutrin, it probably won’t be effective because, as a dopamine re-uptake blocker, it works best with good levels of dopamine release, something people with mu receptor problems don’t usually have.
Definitions are important in medicine. The words we use inform and even decide our actions. ASAM’s new definition of addiction based on the biology of the illness hasn’t made it into the addiction literature yet. In fact, there is no addiction literature yet. There is a body of substance abuse literature and a body of literature on various substance dependencies, but I’ve yet to see a study where the population was a population people with addiction or that excluded those with addiction. If you find one, let me know.