As anyone who’s ever had depression will tell you, the disorder can be frustrating to manage, even though treatment options like therapy or medication can be helpful. In an effort to better understand the mental illness, researchers have suggested in recent years that a "depression gene" or series of genes might play a key role in whether someone develops it. Now, however, researchers from the University of Colorado at Boulder say that actually, there is no depression gene, and that the causes for the mental illness are widely varied and highly complex.
Published in The American Journal of Psychiatry, the new study shows that the 18 most highly-studied genes associated with depression are no more likely to cause depression than randomly selected genes are. According to a press release on the study, researchers analyzed genetic and survey data from 620,000 people via 23andMe, the Psychiatric Genomics Consortium, and the UK Biobank in order to assess if genetics are associated with depression, whether acting alone or when triggered by early childhood adversity. They found that previous studies were yielding false positive results, and that certain ‘candidate genes’ do not cause depression.
“This study confirms that efforts to find a single gene or handful of genes which determine depression are doomed to fail,” lead study author Richard Border, a graduate student and researcher at the Institute for Behavioral Genetics, said in the press release.
“We are not saying that depression is not heritable at all,” study senior author Matthew Keller, an associate professor of Psychology and Neuroscience, said in the press release. “It is. What we are saying is that depression is influenced by many many variants, and individually each of those has a minuscule effect."
While a family history of depression can be a risk factor for developing depression, genetics alone aren’t responsible for why some people develop the disorder, the press release stated. For clinical agencies hoping to develop depression-focused drug interventions and treatments based on genetics, the new findings might put a pin in those efforts. The reasons for depression just aren’t that simple.
“We found that, as a set, these candidate genes are no more related to depression than any random gene out there,” said Keller in the press release. “The results, even to us, were a little bit stunning.”
These findings don’t suggest that the potential connections between genetics and depression shouldn’t be studied anymore, Keller explained in the press release, but that researchers should be wary of overly simplified explanations for complex mood and behavioral disorders. While some health conditions can be linked more directly to genes, depression is much more complex, Keller said.
If you or someone you know is seeking help for mental health concerns, visit the National Alliance on Mental Health (NAMI) website, or call 1-800-950-NAMI(6264). For confidential treatment referrals, visit the Substance Abuse and Mental Health Services Administration (SAMHSA) website, or call the National Helpline at 1-800-662-HELP(4357). In an emergency, contact the National Suicide Prevention Lifeline at 1-800-273-TALK(8255) or call 911.