A recent article in Canada’s Globe and Mail newspaper reported that doctors misdiagnose about 20% of their patients’ illnesses. Wow. If physicians misdiagnose this many physical illnesses, I wondered how accurate they can be when it comes to emotional problems like depression.

As it turns out: not very.

In 2007, a physician named Cepolu looked at the results of 36 studies that had examined physicians’ diagnoses of patients who mental health professionals agreed were depressed. 75% of the physicians were family doctors, while the rest worked in hospitals where they might encounter depression, such as emergency rooms and internal medicine. The results of the single studies were compiled in what statisticians call a “meta-analysis.” The results of the meta-analysis showed that the physicians accurately detected depression 42% of the time. Although the detection rate has improved over the past 15 years, more recent studies show that only 1 in 2 depressed patients is accurately identified.

Physician misdiagnosis is a problem because the first person people normally talk to when they feel bad is their family doctor.

Why is physicians’ diagnosis of depression inaccurate? Patients are partly responsible: they tend to report physical symptoms of depression, such as insomnia, rather than the emotional symptoms, such as feelings of sadness. The way patients present the problem may lead their physician to look for physical causes rather than emotional ones. Even physicians who are knowledgeable about depression may be reluctant to ask about emotional symptoms for fear of upsetting their patients or getting a defensive reaction.

Physicians also tend to think of depression as a purely biological problem, which leads them to be poorly informed about the social causes of depression, which I discuss in my book A Secret Sadness. For instance, life stress is strongly associated with the onset of an episode of depression. Most individuals who experience depression had something very bad happen to them within the month prior to the onset of their depression, particularly a loss, such as the end of a relationship. If a physician is knowledgeable about the social context in which depression occurs, they will take this information into account when considering diagnoses. For example, insomnia in a patient who also tells the physician that his marriage has just ended should be more indicative of depression than insomnia that occurs in the absence of major life stress.

Similarly, a person who had a difficult childhood or who has recently experienced a traumatic event is at increased risk for depression.  If physicians don’t know about the connection between depression and negative life events, both contemporary and historical, they’re unlikely to take these risk factors into account when making a diagnosis.

Another strong predictor of depression is past history. A woman who has been depressed previously is at 40 times the risk of another episode when she experiences life stress.  If a physician doesn’t know the patient’s history of depression, she or he may be unlikely to consider this diagnosis when a woman reports physical symptoms of depression.

The advice in the Globe and Mail article is clear: when you’re trying to get an accurate diagnosis, you’re your own best advocate. If you think you’re depressed, read as much as you can about the symptoms of depression. Then if you strongly suspect you are depressed, read as much as you can about treatments. Many people – and most physicians – think the most effective treatment for depression is antidepressants, but their effectiveness may be due to a placebo effect, as described in a recent 60 Minutes report.  A placebo effect means that the act of taking the medication makes people feel better, not the drug itself.  Both psychological treatments and regular, aerobic exercise have been shown by research to be just as effective as antidepressants. While antidepressants only work as long as you take them, psychotherapy teaches you new life skills and exercise gets you in shape.

In Canada, if you think you’re depressed, the only reason to consult a physician is to get a prescription for an antidepressant. You don’t need a physician’s referral to see a psychologist or counsellor unless your extended health care plan requires a referral to reimburse your treatment.

If you think you’re depressed and you want to try antidepressants, tell your family physician about the specific symptoms you know may indicate you’re depressed. If he or she doesn’t raise depression as a possible diagnosis, ask questions: What else could be causing my insomnia? Is it possible I’m depressed?

To help get you started, here are 14 symptoms of depression:

• Feeling sad or crying easily
• Feeling numb or flat
• Feeling angry or easily irritated
• Feeling you no longer enjoy things as much as you once did

AND

• Not wanting to see people, even friends and family
• Feeling that everything is an effort or lacking motivation
• Feeling tired all the time or having to nap to get through the day
• Sleep problems; either you sleep too much or you wake up after a few hours and can’t get back to sleep
• Appetite problems, either you want to eat all the time or you’re never hungry
• Difficulty concentrating or making decisions
• Feeling critical of yourself for your faults or weaknesses
• Blaming yourself, even for things you know rationally aren’t your fault
• Feeling pessimistic about the future
• Feeling that you’ve failed or are a loser

If you feel any of the first 4 symptoms on a regular basis, that is, at least a few days a week, and 3 or more of the remaining symptoms, you may be depressed. If you consult a physician, don’t forget to talk about the emotional symptoms as well as the physical ones. A licensed psychologist also is qualified to diagnose depression.

© 2012 Valerie Whiffen