What Psychiatrists Treat and Why

The following was originally posted to Thought Broadcast.

Do we treat diseases or symptoms in psychiatry? While this question might sound philosophical in nature, it’s actually a very practical one in terms of treatment strategies we espouse, medications and other interventions we employ, and, of course, how we pay for mental health care. It’s also a question that lies at the heart of what psychiatry is all about.

Anyone who has been to medical school or who has watched an episode of House knows that a disease has (a) an underlying pathology, often hidden to the naked eye but which is shared by all patients with that diagnosis, and (b) signs and symptoms, which are readily apparent upon exam but which may differ in subtle ways from patient to patient. An expert physician performing a comprehensive examination can often make a diagnosis simply on the basis of signs and symptoms. In some cases, more sophisticated tools (lab tests, scans, etc) are required to confirm the diagnosis. In the end, once a diagnosis is obtained, treatment can commence.

(To be sure, sometimes a diagnosis is not apparent, and a provisional or “rule-out” diagnosis is given. The doctor may initiate treatment on an empiric basis but will refine the diagnosis on the basis of future observations, responses to treatment, and/or disease course.)

In psychiatry, which is recognized as a branch of medicine and (should) subscribe to the same principles of diagnosis and treatment, the expectations are the same. There are a number of diseases (or disorders) listed in the DSM-IV, each theoretically with its own underlying pathology and natural history, and each recognizable by a set of signs and symptoms. A careful psychiatric evaluation and mental status exam will reveal the true diagnosis and suggest a treatment plan to the clinician.

It sounds simple, but it doesn’t always work out this way. Psychiatrists may disagree about a given diagnosis, or make diagnoses based on “soft” signs. Moreover, there are very few biological or biochemical tests to “rule in” a psychiatric diagnosis. As a result, treatment plans for psychiatric patients often include multiple approaches that don’t make sense; for example, using an antidepressant to treat bipolar disorder, or using antipsychotics to treat anxiety or insomnia symptoms in major depression.

The psychiatrist Nassir Ghaemi at Tufts has written about this before (click here for a very accessible version of his argument and here [registration required] for a more recent dialogue in which he argues his point further). Ghaemi argues in favor of what he calls “Hippocratic psychopharmacology.” Specifically, we should understand and respect the normal course of a disease before initiating treatment. He also emphasizes that we not treat symptoms, but rather the disease (this is also known as Osler’s Rule, in honor of Sir William Osler, the “founder of modern medicine”). For example, Ghaemi makes a fairly compelling argument that bipolar disorder should be treated with a mood stabilizer alone, and not with an antidepressant, or an antipsychotic, or a sedative, because those drugs treat symptoms which should resolve as a person goes through the natural course of the disease. In other words, we miss the diagnostic forest by focusing on the symptomatic trees.

The problem is, this is a compelling argument only if there is such a diagnosis as “bipolar disorder.” Or, to be more specific, a clear, unitary entity with a distinct pathophysiological basis that gives rise to the symptoms that we see as mania and depression, and which all “bipolar” patients share. And I don’t believe this assumption has been borne out.

My personal bias is that bipolar disorder does exist. So do major depression, schizophrenia, panic disorder, anorexia nervosa, ADHD, and (almost) all the other diagnoses listed in the DSM-IV. And a deeper understanding of the pathophysiology of each might help us to develop targeted treatments that will be far more effective than what have now. But we’re not there yet. In the case of bipolar disorder, lithium is a very effective drug, but it doesn’t work in everyone with “bipolar.” Why not? Perhaps “bipolar disorder” is actually several different disorders. Not just formes frustes of the same condition but separate entities altogether, with entirely different pathophysiologies which might appear roughly the same on the outside (sort of like obesity or alcoholism). Of course, there are also many diagnosed with “bipolar” who might really have no pathology at all— so it is no surprise that they don’t respond to a mood stabilizer (I won’t elaborate on this possibility here, maybe some other time).

The committee in charge of writing the DSM-5 is almost certainly facing this conundrum. One of the “holy grails” of 21st century psychiatry (which I wrote about here) is to identify biochemical or genetic markers that predict or diagnose psychiatric disease, and it was hoped that the next version of the DSM would include these markers amongst its diagnostic criteria. Unfortunately, this isn’t happening, at least not with DSM-5. In fact, what we’re likely to get is a reshuffling and expansion of diagnostic criteria. Which just makes matters worse: how can we follow Osler’s advice to treat the disease and not the symptom when the definition of disease will change with the publication of a new handbook?

As a practicing psychiatrist, I’d love to be able to make a sound and accurate diagnosis and to use this diagnosis to inform my treatment, practicing in the true Hippocratic tradition and following Osler’s Rule, which has benefited my colleagues in other fields of medicine. I also recognize that this approach would respect Dr Ghaemi’s attempt at bringing some order and sensibility to psychiatric practice. Unfortunately, this is hard to do because (a) we still don’t know the underlying cause(s) of psychiatric disorders, and (b) restricting myself to pathophysiology and diagnosis means ignoring the psychosocial and environmental factors that are (in many ways) even more important to patients than what “disease” they have.

It has frequently been said that medicine is an art, not a science, and psychiatry is probably the best example of this truism. Let’s not stop searching for the biological basis of mental illness, but also be aware that it may not be easy to find. Until then, whether we treat “diagnoses” or “symptoms” is a matter of style. Yes, the insurance company wants a diagnosis in order to provide reimbursement, but the patient wants management of his or her symptoms in order to live a more satisfying life.