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The Downside of Genetic Testing for Depression

Picture yourself as a participant in a study: you receive a kit containing mouthwash and a color-changing strip of paper. Sleek text on the professional label reads “Saliva Self-Testing Kit for 5-Hydroxylindoleacetic Acid.” Following the instructions, you rinse your mouth and hold the test strip to your tongue, immediately transforming the test strip from blue to brownish green. While this kit may appear to be a saliva-based genetic test, it is actually a placebo test. However, you were not the only person fooled; 786 participants in the study also believed that the kit was a real genetic test.

In this study, Yale psychologist Woo-Kyong Ahn and Columbia postdoctoral research fellow Matthew S. Lebowitz explored the negative effects of genetic testing for depression, which had been mostly overlooked during the growing popularization of personalized genetic testing for explaining and predicting health issues in the twenty-first century. Public opinion is shifting to believe that depression and other mental disorders, like physical diseases, stem from biological causes, leading to higher interest in genetic testing for mental disorders.

“There was hope that genetic testing would further decrease the stigma around mental health issues,” Lebowitz explained. However, only recognizing the benefits of genetic testing leaves out details about potentially adverse consequences, resulting in a dangerously overoptimistic view of genetic testing. This recently published Yale Thinking Lab study helped show the emotional downside of genetic testing that so often gets ignored.

The researchers divided the participants into three groups: a depression gene-absent group and two depression gene present groups. The test strip turned brown for all three groups, so all the participants received the same placebo test results, but the researchers randomly assigned different meaning to the results. The gene-absent group was told they did not carry the gene that would make them more susceptible to depression, while both gene-present groups were told that they carried the gene.

One of the two gene-present groups watched a short intervention video explaining that genes alone cannot make a person depressed because complicated factors—such as epigenetics, which turn genes on or off, the interactions between many different genes, and environmental and experiential factors—also play important roles in the development of depression. The other group did not. Finally, all three groups completed a Negative Mood Regulation (NMR) scale, which measures how well one expects to be able to control one’s negative emotions in the future.

The gene-absent group reported higher NMR scores than the two gene-present groups, suggesting that the gene-present groups felt less confident in their ability to cope with depressive symptoms than the gene-absent group. In other words, the people who thought they were genetically predisposed to depression felt more helpless and hopeless in regulating their mood, and thus, viewed themselves as more susceptible to depression. “We basically created depression in three minutes,” said Ahn.

Adding further complexity, the gene-present group shown the educational video scored significantly higher on the NMR scale than the gene-present group who did not watch the video. This difference in NMR scores demonstrates that the educational video effectively mitigated the negative effects of the genetic testing on the people who believed that they were genetically disposed to depression.

Personalized genetic testing for susceptibility to depression and other mental disorders is already common among the general public and will most likely become even more prevalent in the future. Ahn thinks genetic testing’s popularity keeps growing because it promises easy answers, even if they may be misleading. “Genetic testing is a way for people to simplify this complicated world, but problems arise with oversimplifying,” said Ahn.

Celebrating only the beneficial aspects of genetic testing overlooks its negative implications, potentially leading to tragic clinical effects. For example, this study showed that genetic testing for depression could actually increase risk for depression because test results showing genetic predisposition to depression exacerbate people’s pessimism in their ability to cope with and overcome depressive symptoms. This negative consequence of genetic testing is especially concerning because faith in one’s own possibility of overcoming depression can be a self-fulfilling prophecy, so abandoning self-confidence can prevent improvement.

The researchers hope their results will spark thoughtful consideration of genetic testing. “I would like for people who are otherwise gung-ho about rolling out genetic testing in all fields to be more cautious,” said Lebowitz.