A 23andMe study published this month provides insight into the cause and overlapping genetics of two mental health disorders – depression and bipolar disorder.
The National Institutes of Health estimates that more than 16 million Americans are affected by depression each year, while nearly 6 million Americans have bipolar disorder.
Genetics and environmental factors — childhood trauma and poverty, for instance — influence the development of both depression and bipolar disorder. Understanding the interplay between those two factors may help researchers develop more targeted treatments.
AFFECT Study
The study, known as the Affective disorders, Environment, and Cognitive Trait (AFFECT) study, looked at data from about 50,000 23andMe customers who consented to participate in research over more than nine months. The study was conducted in collaboration with Lundbeck, a company dedicated to restoring brain health. The research provides a highly valuable real-world dataset, deepening our understanding of two of the most highly impactful mood disorders. Of those participating, 15,000 reported a diagnosis of major depression, and almost 10,000 reported that they had bipolar disorder. The remaining individuals reported having neither condition.
The study collected self-reported data and included background health and demographic information. In addition to genetic data, it incorporated information from a series of online surveys, behavioral assessments, and cognitive tests.
“The AFFECT study represents a unique resource for dissecting the structure of mood disorders across multiple levels of analysis,” the researchers said. In addition, the study’s fully remote nature provides valuable insights for future virtual and decentralized clinical trials within mood disorders.”
Results Consistent with Previous Studies
While these two conditions are different, they share many of the same symptoms. These similarities reinforce the notion that the conditions may fall across a spectrum. Among those overlapping symptoms, the most common were depression, mania, anxiety, and indistinct physical aches and pains. While both those with major depression and bipolar disorder reported sleep problems or substance abuse issues, those two issues were more common among those with bipolar disorder and, according to the researchers, were one of the strongest differentiation points between the two conditions. The study found that symptoms for both conditions often began in pre-teens and often involved some sort of childhood trauma; about 63 percent of those with depression or bipolar disorder reported an adverse childhood experience.
The study is another in a series of studies that 23andMe has either directed or contributed data to advance our understanding of depression and bipolar disorder. The most recent was a study last year by the U.S. Department of Veteran Affairs that included data from more than 1.2 million individuals. 23andMe also contributed data used in a genetic study by the University of Edinburgh published in the journal Nature Neuroscience three years ago. Each has uncovered new genetic associations with the two conditions.
Researchers will continue to study the data from the AFFECT study to find clues about how genetics and environmental factors may combine to impact brain function.