According to new research published in Nature, depression, schizophrenia, and bipolar disorder are linked with ancient viral DNA known as HERVs in our genome.

Ancient viruses have left behind genetic sequences that makeup 8% of human DNA. These sequences are known as human endogenous retroviruses or Hervs, and they have been there for hundreds of thousands to millions of years—some of them even before Homo sapiens appeared on the scene.

According to the most recent research, there may...