Every year around this time, I notice a familiar shift in many of my patients. They start saying things like, “I don’t know why I feel this way,” or “Life is good right now, but I just feel… low.” They can’t quite explain the heaviness that creeps in as the days get shorter.
If you’ve ever felt this way, you’re not alone. What many people don’t realize is that these emotional changes might not be “just in your head.” They could be a sign of Seasonal Affective Disorder (SAD) , a type of depression that follows a seasonal pattern, most often appearing in late fall and winter.
Understanding the science Behind seasonal depression and how to Recognize It makes all the difference in learning how to manage it.
What Is Seasonal Affective Disorder (SAD)?
Seasonal Affective Disorder is a form of depression linked to changes in seasons, most commonly starting in the late fall and continuing through the winter months. It tends to lift as the days grow longer and brighter in spring.
According to the National Institute of Mental Health (NIMH), SAD is more than just “winter blues.” It affects mood, energy, motivation, and sleep , often disrupting daily functioning and relationships.
While anyone can develop SAD, it’s most common in people who live in regions with long winters, reduced sunlight, and colder temperatures.
Why It Happens: The Science Behind the Sadness
SAD is believed to be caused by a combination of biological, environmental, and psychological factors, including:
- Reduced sunlight exposure: Shorter days and less natural light can disrupt the body’s internal clock (circadian rhythm), affecting sleep, mood, and hormones.
- Changes in serotonin levels: Sunlight helps regulate serotonin , a neurotransmitter that stabilizes mood. Lower light exposure can decrease serotonin activity.
- Increased melatonin production: Darkness triggers melatonin, the sleep hormone. Longer nights may lead to excessive melatonin, making you feel sluggish or fatigued.
- Vitamin D deficiency: Since sunlight helps the body produce Vitamin D, shorter daylight hours can reduce levels, influencing both mood and energy.
These shifts can trigger symptoms similar to depression , sadness, fatigue, difficulty concentrating, and loss of interest , but the seasonal pattern is what makes SAD unique.
Who Is Most Affected
SAD can affect anyone, but research shows certain groups are more likely to experience it:
- Women (about four times more likely than men)
- People living far from the equator, where winter daylight is limited
- Individuals with a history of depression or bipolar disorder
- Younger adults , though older adults can experience it too
- People with family histories of mood disorders
Even those who don’t meet full criteria for SAD may experience a “subsyndromal” version, often called winter blues, which still impacts mood and motivation.
Common Signs and Symptoms
If you find yourself noticing these patterns as the seasons change, it might be worth discussing with your healthcare provider:
- Persistent sadness or low mood
- Loss of interest or pleasure in usual activities
- Fatigue or low energy despite adequate rest
- Increased sleep or difficulty waking up
- Changes in appetite (often craving carbohydrates)
- Difficulty concentrating
- Feelings of hopelessness or guilt
One key difference between SAD and major depression is its timing , symptoms appear and disappear around the same time each year.
Understanding It Helps You Manage It
Many people feel shame when they realize their sadness doesn’t “make sense.” They may think, I have everything I need , why do I still feel down?
But the truth is, this isn’t about weakness or ungratefulness. It’s a biological and environmental response.
When we recognize that SAD is real and manageable, we take away its power to make us feel confused or broken.
Understanding the why helps open doors to the how , how to treat it, prevent it, and cope through the darker months.
What’s Next
In my next post, I’ll be sharing natural and evidence-based ways to combat Seasonal Affective Disorder, including light therapy, movement, nutrition, and supplements that have been shown to make a difference.
For now, know that what you’re feeling is valid , and you’re not alone in it. With awareness and the right tools, you can regain balance even in the darkest season.
External Resource
📘 For more information: National Institute of Mental Health – Seasonal Affective Disorder
