Ancient viruses are still lingering in human DNA, but a new discovery has found that some may contribute to psychiatric disorders. Scientists from King’s College London identified five ‘fossil viruses’ associated with depression, schizophrenia and bipolar disorder. The ancient viruses, called Human Endogenous Retroviruses (HERVs), have been previously known but were seen as ‘junk DNA’ with no purpose – but could now lead to new treatments for those suffering with such conditions.