Cold and overcast winter weather inspire countless of indoor activities: s'mores parties, hours of Netflix and more. But for many, the gloomy darkness from autumn to winter is a potent formula for seasonal depression, also known as seasonal affective disorder (SAD).
But a lot of people are more happy in the summer and less happy in the winter, so some consider seasonal depression and SAD to be less-than-serious conditions. However, that's where the researchers from the University of Copenhagen come in.
In a recent study that examines brain scans to understand the science behind and existence of SAD, the Copenhagen team found that people with SAD cannot control the "happy" brain signaling compound of serotonin during the winter months.
The big discovery: "We believe that we have found the dial the brain turns when it has to adjust serotonin to the changing seasons," lead researcher Dr. Brenda McMahon told the BBC.
The brain's dial, it seems, has a lot to do with the amount of one's exposure to natural light.
"The serotonin transporter (SERT) carries serotonin back into the nerve cells where it is not active - so the higher the SERT activity, the lower the activity of serotonin," McMahon said. "Sunlight keeps this setting naturally low, but when the nights grow longer during the autumn, the SERT levels increase, resulting in diminishing active serotonin levels."
By understanding the disorder more technically, scientists and doctors would be more eradily equipped to deal with it in its more severe incarnations.
The researchers studied 11 people with SAD and 23 healthy individuals without SAD, a small, but growing body of work that will be presented this at a neuropsychopharmacology conference in London this week.
A solution for sufferers? For the 10 million Americans who suffer from seasonal depression, there is a glimmer of hope and available treatments including light and cognitive behavioral therapy.
"We know that eating a balanced diet, cutting down on caffeine and getting some exercise can help," McMahon said, "as can spending as much time as possible outdoors because - even when it's overcast - light will be higher than indoors."
The outcome of SERT fluctuations, or diminishing active serotonin levels during the darker, winter months are key to a "happy" brain. This kind of research has been seen in previous studies, but it is the first observation that followed patients from summer to winter months.
"We don't yet know enough about how serotonin levels can be affected by light levels," Sam Challis, information manager at the mental health charity Mind, told the BBC.
Though the study had a small sample of volunteers, it represents a first and important step towards helping treat SAD.
h/t BBC News