Five groups of disorders are found to share most of their genetic risk in a screen of 14 psychiatric conditions — including depression, anxiety and schizophrenia — reported in Nature. The findings, based on DNA data from more than one million people, could help to improve diagnoses and lead to new treatments that work across several conditions.

Psychiatric conditions often occur together and share genetic influences. This can make diagnosis and treatment challenging, as it is difficult to clearly separate the conditions — especially as diagnoses are based on symptoms rather than underlying biology. Understanding the genetic links between psychiatric conditions is important for improving diagnosis and care.

Andrew Grotzinger and colleagues analysed genetic data from 1,056,201 people with psychiatric disorders. They found five genetic factors that explained the majority of genetic variance of the disorders and that connect different sets of conditions: compulsive behaviours, schizophrenia and bipolar disorder, neurodevelopmental conditions, internalizing conditions such as depression and anxiety, and substance use conditions. These genetic signatures were linked to hundreds of genetic regions as well as biological pathways, including some that affect brain cells involved in thinking and emotion.

The findings suggest that shared genetic factors have a role early in brain development and could help to create a more biologically based way of understanding psychiatric conditions. As the current study mainly focuses on people of European ancestry, future research should include more diverse populations and explore how these insights can guide new treatments.