A global study has identified 300 previously unknown genetic risk factors for depression as it included a much broader population.
According to the World Health Organization 3.8% of the population has depression affects approximately 280 million people at any one time.
While a range of factors, including adverse life events, physical ill-health and stress, can increase the risk of developing depression, it also has a genetic component.
An international team of researchers, led by the University of Edinburgh and King’s College London, studied anonymised genetic data from more than 5 million people in 29 countries, one in four of whom were of non-European descent.
Previous research into the genetics of depression has primarily involved white, wealthier populations, neglecting most of the world. But by including a more diverse sample, the authors were able to identify new risk factors.
The studypublished in the journal Cell, found 700 variations in individuals’ genetic code linked to the development of depression, almost half of which had never before been linked to the condition.
These small changes in DNA were linked to neurons in multiple brain regions, including areas that control emotions.
In total, 100 of the previously unknown genetic differences were specifically identified because people of African, East Asian, Latin American and South Asian descent were included in the study.
Although each genetic risk factor for depression is very small, the cumulative impact for individuals with multiple DNA variants may increase their risk, the study found.
The authors believe the findings will allow scientists to more accurately predict the risk of depression, regardless of ethnicity, and develop more diverse treatment options, thereby reducing health inequalities.
The study calculated that 308 genes were associated with a higher risk of depression. The researchers then examined more than 1,600 medications to see whether they affected those genes. In addition to antidepressants, the study found that Pregabalin, used for chronic pain, and Modafinil, used for narcolepsy, also had an effect on these genes and could therefore potentially be used to treat depression. Further studies and clinical trials would be needed to investigate the potential of these drugs in patients with depression, the authors said.
Professor Andrew McIntosh, one of the lead authors of the study and from the University of Edinburgh’s Center for Clinical Brain Sciences, said: “There are huge gaps in our understanding of clinical depression that limit the opportunities to improve outcomes for those affected .
“Larger and more globally representative studies are critical to providing the insights needed to develop new and better therapies and prevent disease in people at higher risk of developing the condition.”
Commenting on the findings, Dr David Crepaz-Keay, head of research and applied learning at the Mental Health Foundation, said the study’s diverse gene pool was “an important step forward” but that genetic risk factors should not be used as definitive evidence . guide to the treatment.
“While this type of research can help shape interventions for those at higher genetic risk, depression prevention should focus on tackling the wider problems in society that impact mental health to a much greater extent, such as experiences of poverty or racism,” he added. .
Dr. Jana de Villiers, spokesperson for the Royal College of Psychiatrists, said: “We welcome this research into the genetic variants that may make people more susceptible to depression, and its diversity in terms of global representation makes it particularly notable. By improving our understanding of genetic risk factors and the causes of mental illness, we may be able to develop better treatment methods.
“We will continue to support ongoing efforts to prevent mental illness and improve outcomes for people affected by depression.”