‘Winter blues’ study finds key to depression resilience

Recently a new study used a model for seasonal affective disorder to find out why and how some people don’t develop depression despite being genetically predisposed to it. The findings also shed light on potential new treatments for seasonal depression.

According  National Institute of Mental Health estimate that over 16 million people in the United States, or 6.7 percent of the population, will have had more than one episode of major depression during the past year. From the research 5 percent live, has been suffering with seasonal affective disorder (SAD), or seasonal depression.The symptoms of SAD are so similar to those of depression that it can sometimes be hard to distinguish between the two. SAD, also known as winter blues, typically affects women. The shocking fact is that, 4 out of 5 people most suffering can been seen in women, and the reasons for this predisposition are likely to be genetic. However, while some people are genetically prone to the condition, they resist the environmental factors that might trigger it.So, new research set out to examine the neurobiology of SAD in an attempt to understand what it actually is that makes some people more resilient to developing depression.The new study was led by Dr. Brenda McMahon, of Rigshospitalet in Copenhagen, Denmark, and the findings were published in the journal European Neuropsychopharmacology.

Previous studies had demonstrated that SAD tends to affect people with a gene called 5-HTTLPR. This gene encodes a cerebral serotonin transporter, a protein that regulates how efficiently serotonin — the so-called happiness neurotransmitter — is removed from the brain.Most antidepressants work by lowering levels of serotonin transporters in order to slow down the removal of serotonin from between the nerve cells.For the new study, Dr. McMahon and team recruited 23 participants — 13 of whom where women — who had not developed depression despite having the 5-HTTLPR gene.The scientists used a positron emission tomography (PET) scanner once in summer and twice in winter to examine the participants’ levels of both serotonin and serotonin transporter. SAD-resilient women downregulate their brain serotonin transporter more in the winter than men do, meaning that the levels of serotonin did remain unaltered between seasons. In general SAD-resilient people maintained the same level of serotonin across seasons.”


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