John, a 38-year-old teacher, started psychotherapy because he was still feeling disturbed two years after his father’s death. In the course of treatment, he became increasingly depressed — to the point where he was having trouble functioning at work. An antidepressant provided a good response. As he continued in therapy, he asked, “Is this really a biological illness, then?” The question illustrates some of the problems we face in trying to integrate our current models of illness and depression.

Psychology vs biology

Ned Cassem, a psychiatrist at the Massachusetts General Hospital, used to tell the following story. He’d walk by a patient who was clearly depressed and in need of treatment, only to be told by the attending physician, something like, “Well, yes, of course she’s depressed, but after all, she has cancer.” Cassem would jump up and down, declaring that understanding the cause of the depression didn’t preclude treating it with medication.

Here’s the problem: many of us, particularly psychotherapists, are used to seeing depressed mood as signalling a psychologic problem — inner conflict, cognitive distortion — that can be addressed by psychotherapy. But when a DSM-IV major depression is diagnosed, a syndrome where low mood is bundled with neurovegetative disturbances i.e. of sleep, energy, sex drive, etc., we know that it may respond to treatment with antidepressants. The possible meaning of the low mood isn’t relevant in this model — though that in no way means that it doesn’t matter to the patient.

If the person meets the DSM-IV criteria, medication is one treatment option. However, although virtually all the literature to guide the use of pharmaceuticals is based on trials using DSM diagnoses, this doesn’t invalidate the idea that the affect has meaning: one diagnosis doesn’t exclude the other. These are basically different etiologic models that aren’t yet integrated.

Some patients may prefer to think they have a biologic illness, perhaps taking the issue out of their hands, while others will resist the idea, feeling that it suggests they have little control over how they feel. A response to treatment — whether medication or psychotherapy — says nothing about etiology. So asking the question, “is it really biological?” implies a false dichotomy. Mounting evidence shows that physiology affects psychology and vice versa.

Meshing the 2 models

John’s question reflects the difficulties patients have in integrating different models of illness. Yes, he has a biologic syndrome that’s been shown to respond to antidepressants. At the same time, the death of his father triggered a mourning process. He grieved not not just for his deceased parent but also for the closeness he was never able to achieve. In a combined treatment, both the physician and patient have to find a way to shuttle back and forth between models, allowing them equal status and not privileging either. While medication helps to reverse the mood and neurovegetative disturbance, psychotherapy knits together a narrative of this depression’s meaning, and assists the person in building the psychologic tools to deal with it.