New research suggests that another gene, independent of influences of dopamine, norepinephrine and serotonin levels, may be responsible for predisposing an individual to a major depressive disorder. The genotype is responsible for influencing the levels of neuropeptide Y (NPY).
NPY is a brain chemical which is responsible for calming a person after experiencing stress. People with the identified gene were prone to developing a major depressive disorder due to having low levels of NPY.
The study was performed on 179 patients, 44 of which were diagnosed with a major depressive disorder. One test done was showing the participants a number of words with a negative connotation. Electrical impulses in the brain were monitored, and those with lower NPY showed stronger responses to this test. The next test was to inflict pain on the participants, where the scientists were able to measure the responses to stress. Those who had lower NPY were more affected by the test as compared to those who were healthy. The last test performed was to compare the levels of NPY between the healthy participants and those who had some form of a major depressive disorder.
The researchers then concluded that individuals who had the gene responsible for lower NPY levels were more prone to having a depressive disorder.
The results of this study would be of great help to the future developers of treatment options for individuals with a major depressive disorder, as they can now identify the gene which could be the focus of future treatments.