Psychiatrists often try two or more medications in a patient suffering with major depression before settling on the one that seems to work best for that individual. Sometimes, after several are tried and abandoned, two (or even three) are used in combination.

Medication selection is part of the art of psychiatry, but, now, testing is available that promises to make it more of a science. A company called AssureRx Health now offers what it calls GeneSightRxpharmacogenomic laboratory testing that helps identify which antidepressants are a good match for a persons genetic makeup, and which are not so good a match.

Sometimes, the testing reveals why three or four antidepressants havent worked for a patient, while pointing in the direction of one that might.

This is extremely good news, because psychiatrists have several different kinds of antidepressants to choose fromsome which increase the activity of the brain chemical messenger serotonin, some which increase the activity of the brain chemical messenger norepinephrine and some which increase both. And they do so by varying mechanisms, requiring the activity of different enzymes.

The technology behind GeneSightRx actually determines which genetic variantsin terms of the enzymes that are activated by antidepressantsa person possesses.

Different antidepressants affect the enzymes very differently. Hence, the testing can literally predict with some accuracy which antidepressants are likely to work in a particular person, and which are likely to cause the fewest side effects.

Recent studies have revealed that antidepressants dont work much better than placebo medications (sugar pills) for many patients. But those studies werent conducted by first selecting patients who are more likely (as determined by GeneSightRx) to respond to the particular medicine being studied.

Its very possible that patients given medications suggested by such testing would do far better than those given placebosbecause they arent being lumped together and given one medicine, regardless of their individual genetic makeup.

Moreover, since many patients discontinue their antidepressants due to side effects like sexual dysfunction and sleeplessness, choosing a medication that is metabolically and genetically less likely to cause these and other side effects makes good sense.

GeneSightRx also predicts which ADHD medications, antipsychotics and pain medications patients are likely to respond to and from which they are likely to experience fewer side effects.

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