by: Peter Roy-Byrne | Jan. 23, 2019
Many of our patients are inquiring about whether they should be obtaining a “genetic test” to help select the best antidepressant for them. We have followed this area of research with great interest and careful scrutiny, and at the present time, there is little reason to obtain such a test.
Another area of genetic testing involves the MTHFR gene. While this area of genetic testing may have some utility, it remains early and the literature demonstrates that other laboratory testing, such as homocysteine, seems to be a more reliable indicator of whether methyl-folate might be beneficial. Please read the following brief review of this area, written by an expert clinician psychiatrist. The first summarizes a recent study on this topic that supposedly “proves” the value of this testing. https://www.jwatch.org/na48275/2019/01/18/genetic-testing-improve-antidepressant-selection-redux. The second reviews this area in a bit more detail. https://www.jwatch.org/na44895/2017/08/31/when-genetic-testing-unproven-case-depression-treatments .
The FDA has also issued a statement about this issue https://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm624725.htm and the Southern Investigative Reporting Foundation has also written an article which details how these tests are being marketed to the public and to practicing psychiatrists without adequate evidence of benefit for patients. http://sirf-online.org/2019/01/07/myriad-genetics-this-company-has-great-difficulties-telling-the-truth/
No study has made the prescribing physician “blind” to the fact that their patient is going to have their medication guided by a genetic test. This means that any small benefit (and the recent supposedly definitive study only showed a VERY small benefit) is almost certainly due to the physician unwittingly communicating enhanced hope and optimism to the patient. For anyone doubting that this is likely to happen, please look at this recent study, which showed that an expectation of receiving genetic information will cause changes in that direction, even if the genetic information is false. https://www.nature.com/articles/s41562-018-0483-4