A remarkable genome-wide association study revealed new genes which are associated with depression and demonstrated that the genetic risk factors for depression in East Asian populations differ from those with European ancestry.
With a total of 194,548 participants, this study, published in JAMA Psychiatry on 29 September 2021, is the biggest cohort of non-European participants ever evaluated for genetic risk of depression. Researchers spent two years merging data from numerous studies of people of East Asian heritage (from mainland China, Taiwan, the UK, and the US).
To date, the majority of research done on the genetics of depression has enrolled mainly European participants. However, this large cohort study of East Asians found that only 11% of the 102 genetic variations for depression that have been identified in previous research done on European participants were linked to depression in East Asian participants.
Five new genes have also been found that may raise the risk of depression in East Asians. This demonstrates that not only are the bulk of genetic variations linked to depression in Europeans not applicable in East Asian cohorts but additional genes that had not been identified in studies on Europeans were also uncovered in East Asians.
‘We were surprised to find many differences in the depression genes for Europeans and East Asians, which shows the need to increase the diversity of samples in these types of studies and to be cautious about generalising findings about genes in causing depression,’ said the study lead Dr Karoline Kuchenbäcker, a genetic epidemiologist from University College London (UCL).
In addition, this study discovered that East Asians with higher body mass index have a decreased risk of developing depression, contrary to what was previously discovered in European populations. Furthermore, researchers contrasted East Asians living in the US and the UK with those in China and Taiwan. The investigation revealed distinct genetic variations linked to depression in the two cohorts, suggesting that sociocultural or environmental factors may also alter how the genes influence the risk for depression.
‘Genetic research has the potential to contribute to new treatments. But if the foundational research did not involve appropriately diverse study populations, then new treatments might not work the same for everyone, and may contribute to health disparities,’ said Professor Kuchenbäcker.
Finding these genetic differences can help predict a person’s risk of getting depression and may also help identify the genes and proteins that contribute to the mental disease, ultimately aiding with new treatment options specific to geographical locations and ethnicities.