A brief poll of my scientific colleagues confirmed that, to a person, they regard addiction as a disease, whereas most non-science acquaintances consider it to be a failure of willpower. Reconciliation of these polarized views seems difficult and rather than finding a middle path, such as suggested by Foddy and Savulescu. I am an entrenched supporter of the view that addiction can be a disease. I first should declare my position as a card-carrying biologist, holding the view that behavior emanates from the brain and, accordingly, that behavior and emotions result from brain function. This brain function also produces addiction and related behaviors, whereas Foddy and Savulescu seem to credit humans with a greater capacity to choose than biological evidence suggests. The second problem relates to definitions of disease: I argue that there are at least three ways addiction might be considered a disease.
1. Addiction is a disease because it results in pathology. For example, hypertension is a disease. Hypertension per se does not cause dysfunction, but leads to pathologically definable conditions such as stroke and myocardial infarction. Smoking, like hypertension, can result in pathologies such as emphysema and cancer. The problem is not smoking per se, or even addiction to nicotine, rather it is the consequent diseases caused by tobacco. Nevertheless, if hypertension is a disease, so is smoking. The question of "choosing" to persist with smoking has no bearing on whether it is disease. Whether a person chooses to care for their hypertension or ignore it does not alter the fact that they have hypertension; it is still a disease and it will still harm them. Whether addiction affects the capacity to choose is not relevant because it does not alter the fact that smoking causes pathology and hence is a disease.
2. Foddy and Savulescu argue that addiction leaves no tell-tale pathology to set it aside from normal physiology. Although this claim is debatable, disease can nevertheless be present without measurable pathology, especially if it causes dysfunction. There is no diagnostic test or hallmark pathology of schizophrenia, which nevertheless is a devastating disease. Undoubtedly, future research will reveal the pathology, but the same arguments hold for addiction, which can also have devastating effects on quality of life, social integration, and employment, and eventually destroy health and life without pathognomonic pathology or tests. There are two points to be made: Disease can be present without us knowing the nature of the pathology, and dysfunction in itself is sufficient to call a process a disease.
3. Disease and normality lie at opposite ends of a continuum: The extremes are readily recognized, but the boundaries can be difficult to define. Cancer is unambiguously a disease, but the border between malignancy and benign hyperplasia can be difficult to define. Blood pressure and cholesterols levels are other examples of spectrums, risk of pathology being directly proportional to blood pressure or serum cholesterol. Low is clearly normal whereas trouble is inevitable with extremely high levels of either cholesterol or blood pressure: But where does the border lie? Addiction is also a continuum and it has been recognized for over 500 years that at one end of this continuum, addiction takes a form in which people lose control, or autonomy, to the addicting agent. [End Page 31]
The first meaning of addiction was to "give over" or cede control in legal sense, and long before addiction carried its modern opprobrium, it was recognized that some addicted people cede control to the addicting agent. This is demonstrated by the alcoholic, who has lost job and family, who suffers from delirium tremens, and has brain injury and liver failure from alcohol, yet continues to drink. It becomes difficult to argue that this person acts autonomously. Although some addiction may not be pathological, it does not follow that none are. To mix the caffeine addiction of the functioning middle class with the broken life of the street addict seems to be mixing categories. Although both may be addicted, according to the definitions, one has a disease but the other does not.
Thus, there are at least three ways that some addictions...