There is an important distinction between feeling sad and experiencing depression. Sadness is part of the human condition, but suffering from prolonged depressive symptoms reflects an underlying medical condition that can be extremely destructive. Virtually no one wants to be depressed and many people have taken antidepressants in the hope of finding relief. In very general terms, about half of the patients who faithfully take a modern antidepressant will experience a complete remission of their symptoms within two months. Unfortunately, half of the patients will not experience this degree of relief although some of them may feel somewhat better. Until relatively recently, it was a matter of playing the odds and hoping that the medication would work for you.
In 2004, it became possible to increase the odds that the first antidepressant that a physician selected would work. It still wasn’t possible to be certain that that the first selected medication would result in a remission of symptoms, but the odds got better. This breakthrough was the result of a genetic test that the FDA approved that identified some people who would not respond to some medications and other people who had a high probability of not being able to tolerate taking certain types of medication. This improvement was the result of testing for variations in only two genes.
Some doctors were unimpressed by this advance and questioned whether the cost of the test was worth improving the odds of picking the right medication. Not surprisingly, most patients were grateful that it was possible to improve their chances of responding to the first medication they tried.
Since 2004, other genes have been identified that have variations that effect antidepressant response. This has resulted in further improvements in a physician’s ability to identify medications that patients will be able to tolerate and that will relieve their symptoms. Currently, doctors can order a panel of several genes that are relevant to the prediction of a therapeutic response for less cost than the original expense of the two gene test. Given the research that is being done to improve the prediction of medication response and the dramatic decrease in the cost of genotyping, in a few years it may be possible to genotype dozens of relevant genes for the price of a panel of five genes today.
We are still not able to predict with certainty which medication will work for which patient. However, we have definitely improved our ability to increase the odds of having a good response when we prescribe an antidepressant. Economists are still trying to figure our how much money this testing will save in terms of health care costs. While there is no question that decreasing cost is important, patients are far more interested in finding a medication that will help them to feel better and in decreasing the odds that a medication might actually make them feel worse.