All the confusion about defining “mental disorder” makes sense when one thinks about the term more carefully. Mental has to do with mind and disorder is often (though not always) a euphemism for disease. So, another way to think about mental disorder is as some kind of “mind disease.” Of course, as Thomas Szasz (1974) pointed out more than 50 years ago, mind or perception are products of our brain but – unlike brain – are not tangible, and so, in a literal sense, they cannot be afflicted by diseases.
Mental disorders fall into two likely categories: (a) everyday problems in living that warrant professional attention but are not diseases, and (b) suspected brain diseases whose etiologies may one day be uncovered but currently remain unknown.
Given a commitment to an atheoretical position on etiology, the prospect of changing the definition of mental disorder to one that explicitly defines disorders as “psychobiological dysfunctions” is big news indeed because doing so is overtly theoretical. Psychobiology conceptualises human psychology as something that can be reduced to and explained exclusively in biological terms. As such, the proposed new definition of mental disorder contends that all diagnostically defined disorders have biological causes.
Moving in an openly biological direction might make sense, but only if the diagnostically defined mental disorders are restricted to disorders where the underlying biological causes are known. As Thomas Szasz said “I have tried to show that for those who regard mental symptoms as signs of brain disease, the concept of mental illness is unnecessary and misleading. For what they mean is that people so labeled suffer from diseases of the brain; and, if that is what they mean, it would seem better for the sake of clarity to say that and not something else.” In other words, if there will be a shift from an atheoretical to a psychobiological stance, it should probably have pretty clear evidence that the mental disorders it contains can be diagnosed using biological tests or markers. Yet, this is not the case, while all diagnostic manuals explicitly refer to the current unknown causality of the defined mental disorders.
In cases where mental disorders are diagnosed and treated successfully with medication, we cannot say whether there is a specific underlying biological cause and whether is being remedied. Improved mood notwithstanding, whether we have cured something remains the subject of speculation because, when it comes down to it, we just don’t know enough to say with certainty what the underlying biological cause of any given mental health condition actually is in the first place. We must keep in mind that changing a person’s experience and behaviour (for example regulation of stress, sleep, diet) doesn’t necessarily mean we have corrected a psychobiological dysfunction. To feel confident that medication cures an underlying disorder, we need to know whether the mental disorder can be solely attributed to biological etiology and how medication “fixes” that etiology.