Not only have genetic factors been associated with risk for depression, so too have they been associated with treatment response. In this case, reports have shown that variations in genes associated with the chemical messenger norepinephrine (see June 17, 2010 blog) and genes for a compound that regulates cortisol are associated with response to treatment. Just as variations in the serotonin transporter have been associated with risk for depression (see July 27, 2010 blog below), variations in the transporter for norepinephrine have been associated with treatment response.
In a study looking at the response to the medication Milnacipran, an SNRI (see June 27, 2010 blog), which is actually approved in this country for Fibromyalgia but in Europe for Depression, one specific variation in the transporter gene was associated with a particularly good response and another specific variation with a poor response to this medication. Looking at the response to the SSRI Celexa, the variation in a single point on the gene that controls cortisol levels was significantly associated with whether someone did well. Although tests for these gene variations are not available outside of small research studies, they definitely represent the future of psychopharmacology, and mirror progress in other medical specialties.
For example, there is a blood test available that can predict which patients will not benefit from the blood thinner Plavix. Anecdotally, it has always been thought that family history of response to a particular medication may predict a patient’s response. We know that family history is simply an indicator of a person’s genetic makeup. Hopefully, in the future, we will be able to formalize this with specific easily obtained genetic tests to further inform treatment options.
Regards, Dr. Ranen (Psychiatrist Baltimore, Baltimore County, Owings Mills) DrNealRanenBaltimorePsychiatrist.com