Wednesday, October 17, 2018

Wisdom Wednesday: ‘Winter Blues’ Study Fined Key to Depression Resilience

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

The National Institute of Mental Health estimate that over 16 million people in the United States, or 6.7% of the population, will have had more than one episode of major depression during the past year. A further 5% live 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. In fact, 4 in 5 people with the condition are 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 Neuropsycholpharmacology.

As Dr. McMahon and her colleagues explain, seasonal depression is caused by insufficient daylight, making the condition more widespread in countries that are father from the Equator. She says, “Daylight is effectively a natural antidepressant. Like many drugs currently used against depression, more daylight prevents serotonin [from] being removed from the brain.

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.

For the new study, Dr. McMahon and team recruited 23 participants – 13 of whom were women – who had not developed depression despite having the 5-HTTLPR gene. The scientists used positron emission tomography (PET) to scan once in the summer and twice in the winter to examine the participants’ levels of both serotonin and serotonin transporter.

“We found,” explains Dr. McMahon, “that the level of serotonin transporter protein dropped by an average of 10% from summer to winter, with the drop being noticeably greater in women.” However, the study found that people who were resilient to SAD downregulated their levels of the serotonin transporter during the winter.

“This is the first time anyone has used PET scans to look at resistance to winter depression” says Dr. McMahon. She adds, “Our findings offer good grounds for treatment of SAD with SSRI (selective serotonin reuptake inhibitors).

My Take:
I found this study very interesting. However, rather than give patients suffering from SAD an SSRI antidepressant, I suggest more exposure to daylight and vitamin D supplementation. Studies have indicates that 90% of Americans are deficient in vitamin D and lack of exposure to daylight is a part of the problem. Even in inclement weather, going outside during daylight modulates serotonin levels, just to lesser extent.

Bottom Line:
Stay away from SSRIs for SAD. Take 4,000 IU of vitamin D3 daily and get outside.

Source: October 7, 2018 NIH

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