CU Boulder researchers have reviewed several investigations that had for the last 25 years singled out ‘candidate genes’ as causes for depression. It was seen that 18 of these genes had already featured for a minimum of 10 times in earlier studies. Data collected from hundreds of thousands of individuals were then used to show that any random gene was as responsible for depression as the 18 candidate genes. Results debunking the ‘candidate gene hypotheses’ were published in American Journal of Psychiatry. Richard Border, the first study author, said that all studies attempting to single out particular genes as causes for depression are sure to fail. Matthew C. Keller, senior study author, said that scientists and researchers working in the genetics field had rejected the idea of candidate genes a very long time ago, but many others from different fields like psychology have tried to pursue the ‘candidate gene hypotheses’, seemingly even finding proof and evidence to support the idea. For example, gene SLC6A4 that codes for a protein working with transport and serotonin recycling in the human brain was listed as one of the candidate depression genes. People with experiences of childhood trauma and having shorter variants of the gene could be more likely to suffer from depression, said previous studies. Dr. Keller ruled out all possibilities for any such thing.
Feelings of loneliness and sadness are a part of everyday life during times of loss and high stress. Depression, on the other hand, is a psychiatric disorder with persistent and severe symptoms. People stop interacting socially, studying and working due to major depression, the most widespread form of depression. Huge numbers of people in the US are affected by depression every year.
Dr. Keller and team studied data from about 620,000 individuals. Researchers searched for connections between depression due to socioeconomic adversities or physical abuse during childhood and the 18 depression candidate genes. However, no solid proof was found. Dr. Keller and team emphasized on the fact that depression and its causes are not as straightforward as they are thought to be. They said that in order to link genes and depression, ‘polygenetic scores’ are required.