Researchers from multiple countries have collaborated to correlate a number of genetic variations with specific mood disorders. This massive genetic association study revealed that specific changes in DNA sequences can result in genetic predisposition to mental disorders such as depression and neuroticism
Depression is a condition characterized by anxiety, low energy, bodily aches and pains as well as pessimism. Neuroticism is a personality trait characterized by easily experiencing negative emotions such as anxiety and fear. These mental conditions can be significant sources of work absenteeism or can even result in a person committing suicide. Stigmatization and shame surround these conditions because people still do not accept that they are diagnosable diseases.
In their recent publication in Nature Genetics, Okbay and colleagues investigated the genetic relation between depression and neuroticism, and subjective well-being, which is measured by survey questions on life satisfaction, positive affect or happiness. They showed that depression, neuroticism and low subjective well-being are frequently linked with particular variations in DNA sequences in some of the genes related to the central nervous system, adrenal glands and pancreas tissues.
Genome-wide association studies use the DNA sequence of several individuals and intend to correlate variations in these sequences with specific characteristics, such as eye color or height. When it comes to emotions, well-being, or depression, the environmental factors that influence these parameters confound the data. Therefore, the number of DNA sequences analysed need to be huge in order to produce relevant results. In Okbay’s study, the researchers used the data from 59 cohorts that included DNA sequences from more than 600,000 patients, in order to have a statistical power sufficient to draw valuable conclusions.
Researchers discovered 16 genetic variations linked to these factors: 2 associated with depression, 3 associated with well-being, and 11 associated with neuroticism. Their research also highlighted a high level of genetic correlation between the three factors (subjective well-being, depressive symptom and neuroticism). Indeed, they demonstrated that genetic variations associated with depression and neuroticism were also associated with low subjective well-being. This means that genetic influences are probably related to common processes, such as mood, rather than being specific to one precise type of metal disorder.
In a nut shell, if your genome contains these precise genetic variations, you have a genetic predisposition, and are more susceptible to suffering from depression or neuroticism than the rest of the population.This study is a first step that will allow the development of better medication to treat these mental conditions. As well, these genetic variations could be used screen genomes in order to identify individuals who are at a higher risk of developing mental disorders.
Written By: Jean-Michel Bourget PhD