Doctors call it Seasonal Affective Disorder (SAD) and scientists believe that around 10 million Americans suffer from what is known as the “winter blues.” The last thing I want to write about is SAD and I know some people don’t warm to the topic. But those who know me best know I’ve had a problem with depression for years. I dutifully take two tablets a day and work very well.
I can’t say I’m taking the pills and I doubt anyone else can, too. But let me miss you for a week or two and “the black dog” will begin to circle, as Sir Winston Churchill called his depression. I am very open about my depression in the hope that I could inspire a “campaigner” to get help and feel as good as me.
In my opinion, mental health is as common as physical – no shame – and in most cases it is treated with no problem by a professional doctor.
‘The Winter Blues’ are very real and in the worst case scenario can lead to dark places. There are more suicides between Thanksgiving and Christmas than any other time of the year. Do you know how many people can benefit from a brisk walk in the winter sun? The article you’re about to read proves it. And if you find yourself in a place where the problem may be more serious than Seasonal Affective Disorder, you may need to take two simple tablets every morning like I do … under medical supervision, of course.
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INSIGHTS INTO THE SEASONAL AFFECTIVE DISORDER
By Liz Schondelmayer, Michigan State University.
As the days get shorter and colder, it is likely that you or someone you know is experiencing seasonal mood swings.
Symptoms such as loss of energy, low mood, lack of interest or difficulty concentrating can often be attributed to the lack of daylight that we take in. If these symptoms get too bothersome, they can indicate a mood disorder called. point out Seasonal Affective Disorder (SAD).
Over 10 million Americans have SAD, a type of depression that affects people during the fall and winter months when access to light is restricted. But how does light play such an important role in moderating mental and cognitive health?
Lily Yan, Associate Professor in the Department of Psychology at Michigan State University (MSU) and Director of the Light, Emotion, and Cognition Laboratory, explains how exposure to light affects our mood, memory, and motivation.
Reporter: First of all, what is seasonal affective disorder and what are the symptoms?
Lily Yan: SAD is a form of major depression that is characterized by a seasonal pattern of depressive symptoms for at least two consecutive years. While many of us may not meet the exact diagnostic criteria for severe depression in winter, we can still experience a milder form of these symptoms, often referred to as “winter blues.”
Most people who suffer from this type of depression don’t necessarily feel sad, but instead struggle with an energy crisis that causes them to constantly feel tired, withdrawn from social activities, sleep well, and focus or concentrate.
Reporter: When did you start working on this topic and how do you research?
Yan: My research so far has focused on understanding our circadian rhythm (our body’s natural 24-hour sleep-wake cycle) and how the circadian rhythm is affected by ambient light conditions. Since joining MSU in 2008, I began researching how light affects emotions and cognition, as these functions are known to be influenced by the circadian system. In 2012, I received a grant from the National Institute of Mental Health to start the research program on Light, Emotion, and Cognition.
The phenomena behind SAD have been known for decades, but I feel that there is still a void in the literature on the subject: we don’t know enough about how light affects our mental health. This research can be challenging because it is difficult to use human subjects to study neurobiological mechanisms and most laboratory animals are nocturnal and react differently to light than humans. However, […] we have a very unique resource: a diurnal rodent model (meaning they are awake during the day, just like humans). With this model, my research program aims to understand how light interacts with our brain at the molecular, cellular and circuit level.
Reporter: How does light affect the mechanics of our brain that underlie our mood and cognition?
Yan: The prevailing theory in this area is that light affects our circadian rhythm by training our brain’s internal clock and synchronizing it with our surroundings. However, when changes in the light cycle disrupt our circadian rhythm, it can lead to cognitive and emotional problems such as irregular sleep patterns and moodiness.
In addition to regulating the circadian rhythm, previous research has shown that seasonal lighting conditions can affect the amount of neurotransmitters (like serotonin and dopamine) present in the brain – which means your brain actually stores more of the chemicals you produce for itself during the summer months feel happy, alert and motivated.
When we move from a bright, sunny season to a dark, cloudy season, changes take place in the brain on an anatomical level. The results of a study that involved over 400 subjects show that the hippocampus – the part of our brain that controls many of our cognitive functions such as learning and remembering – is actually physically smaller in winter and changes depending on the season.
Reporter: How does rodent research provide broader questions about human emotions and cognitive function?
Yan: When working with diurnal rodents, we find that many of their behavioral and neurobiological responses to light are the same as those of humans. In this research, we only change one factor at a time, which is the amount or intensity of light that the rodents receive during the day. We have found that limiting their daylight exposure leads to many changes in behavior: for example, the rodents have difficulty feeling joy and / or remembering things.
Rodents generally like things that taste sweet, but after a few weeks in a wintry twilight, they stop caring about sweets and just eat what is most readily available. But in a regular state with more light, they get excited about the sweet treats again and try to get hold of them. In addition, we see a lower sex drive in males who are housed in low light. The animals that are kept in dim light also have lower levels of serotonin and dopamine in their brain than those in bright light. These results help establish diurnal rodents as a useful model to study the effects of light on the brain that are relevant to SAD in humans.
We also conducted research to test the effects of daylight exposure on rodents’ spatial learning and memory. When navigating a maze, the rodents housed in a dim light have difficulty remembering the course, but the animals in a bright light are able to complete the maze. We also found that in low light conditions, there are fewer dendritic spines (which allow neurons to receive information) connecting neurons in the hippocampus. This could explain why information is more difficult to process and store when we are less exposed to daylight.
Further research has shown that a neuropeptide (a type of neurotransmitter) called orexin plays a role in regulating light-dependent changes in learning and memory. In a recent study, we gave rodents kept in a winter-like state this neuropeptide for five days in a row every day and found that their ability to learn and store new information improved significantly. On the other hand, when we gave treatment to rodents in a summer-like state that blocked their ability to absorb orexin, the rodents’ cognitive abilities were impaired. These results suggest that orexin is an important neurotransmitter in mediating the effects of lighting conditions.
Our future work will aim to further elucidate the neural mechanisms underlying the effects of bright sunny days or darker cloudy days on the brain, from the level of gene expression to neural circuitry. The diurnal rodent model offers the opportunity to answer these questions, which can be transferred to the understanding of SAD and winter blues in humans.
Reporter: Given this understanding of SAD and the winter blues, what options are there to relieve SAD-like symptoms in winter?
Yan: If you want to make a diagnosis or need help treating a SAD case, I advise you to seek professional help from a psychologist first.
However, if you just want to boost your energy or motivation during the winter months, I definitely recommend spending more time outdoors. Even if the cold weather can make it difficult, the outdoor lighting is still much brighter than the indoor lighting, even on a cloudy or overcast day. You could also look into a light therapy box to make the interior lighting even brighter.
I hope that a better understanding of the mechanisms underlying the effects of light on mood and cognition will lead to the development of new strategies for treating SAD as well as other types of depressive disorder and cognitive impairment in the future. Until then, light will remain one of the most effective treatments for SAD and winter blues.
For my undergraduate classes, I always share the following quote from Albus Dumbledore: “Happiness can be found even in the darkest of times, as long as you remember to turn on the light.”
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(This article was originally published by Michigan State University. Republished through Futurity.org under a Creative Commons License 4.0 and reprinted in The Epoch Times on November 26, 2021.)