Although the stigma once associated with mental illness has receded in recent years, most of the 12 million Americans who have clinical depression still don't get treated for it, partly because many are too embarrassed to go to a psychologist. In fact, according to mental-health professionals, the majority of depressed people who seek professional help turn first not to a psychologist but to their primary-care physician.
But do regular doctors really know how to identify depression? A large new scientific review published July 30 by the journal Lancet suggests they don't. In a review of 41 previous studies involving more than 50,000 patients in developed nations around the world, the authors found that general practitioners make frequent mistakes, missing true cases of depression about half the time and incorrectly diagnosing it in 19% of healthy people.
Alex Mitchell, Amol Vaze and Sanjay Rao of Leicester General Hospital in the U.K. estimate that about 1 in 5 people in developed nations will experience depression in their lifetime. That means that among a general patient population of 100, about 20 will develop the condition, but the typical doctor will find it in only 10 of those who have it. And among the 80 healthy people, the doctor will incorrectly identify depression in 15.
This is significant because depression — especially if it goes untreated — can be debilitating for the patient and his or her family. Depression also carries an enormous societal burden, leading to missed work days, loss of productivity and increases in health-care spending for co-occurring conditions like sleep problems or anxiety. Further, those misdiagnosed with depression may end up being prescribed antidepressant medications that not only cost a lot but can have serious side effects, including lethargy and sexual dysfunction.
The various studies that Mitchell, Vaze and Rao reviewed used different methods to verify whether doctors had missed depression in their patients. In some of the studies, researchers went back over case records and picked out patients who appeared to have the illness. In other studies, researchers interviewed patients and made diagnoses in person. But virtually all the studies pointed to the same conclusion: general physicians aren't very good at recognizing the most common mental illness in the world.
Why? One reason is that the typical doctor visit — even in wealthy nations — is quite short, usually no longer than 15 minutes. It's hard for patients, who may already be reluctant to discuss depression, to open up about their symptoms during that brief period. The authors of the paper suggest that doctors should spend more time or schedule follow-up appointments with patients they suspect have depression; research has shown that such follow-ups can dramatically increase the rate of accurate diagnoses.
That's surely a worthy goal, although, at least in the U.S., it offers a classic example of the incentive problems in the current health-care system: if general practitioners spend extra time with each patient trying to diagnose psychiatric problems, they will see fewer patients in a day, which means fewer reimbursements overall from the insurance companies. So is there another way?
Maybe. One method might be to write diagnostic criteria for depression that are sharper than the loose catalog of symptoms used today. The current Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association (APA), lists such vague symptoms as "fatigue" and "indecisiveness" as possible markers of depression. And while the definition must be broad enough to encompass a disease that manifests in many different ways in many different patients, even mental-health specialists hotly debate what constitutes true depression. A commentary in the Lancet accompanying the new paper asks, "If the diagnosis of depression cannot be agreed satisfactorily by the best minds in psychiatry, why should we expect the general practitioner to be a reliable assessor of the condition?"
A large contingent of APA specialists is currently rewriting the diagnostic manual, but the revision won't be out until at least 2012. In the meantime, most people will probably continue to use their general physician for front-line psychiatric care. That may be preferable to not seeking care at all, but for high-risk patients — such as those who have a family history of depression, recent stressful life events, chronic illness or substance abuse — it would be wiser to seek specialized attention.