As we move through February, many of my patients walk into the clinic describing a similar “heaviness.” They’re sleeping longer but waking up tired; they’re craving carbohydrates; and that spark of motivation they felt in January seems to have evaporated.
In common parlance, we call this the “Winter Blues.” But as a physician, I want to discuss when those feelings cross the threshold into Seasonal Affective Disorder (SAD)—a clinically recognized form of depression with a very real biological basis.
It’s Not “In Your Head”—It’s Your Hormones
SAD isn’t a lack of willpower; it is a physiological response to the changing environment. Your brain relies on sunlight to regulate its internal clock, and when that light disappears, three major things happen:
- Circadian Rhythm Disruption: Your internal biological clock (the suprachiasmatic nucleus) gets “out of sync” when light exposure is low, leading to grogginess and sleep disturbances.
- The Serotonin Drop: Sunlight triggers the brain to release serotonin, the neurotransmitter responsible for mood and focus. Without it, serotonin levels can plummet, leading to feelings of depression.
- The Melatonin Overload: Darkness signals the body to produce melatonin. In the winter, the lack of light can cause the body to overproduce melatonin, leaving you feeling lethargic throughout the day.
The Physician’s Toolkit for Recovery
While we can’t change the weather, we can change your biological response to it. Here is how we treat SAD clinically:
1. Phototherapy (Light Boxes)
This is the gold standard for SAD treatment. Using a 10,000 lux light box for 20–30 minutes within the first hour of waking can mimic the outdoor light you’re missing. It signals your brain to stop melatonin production and start serotonin production.
2. Strategic Vitamin D3 Supplementation
Vitamin D acts more like a hormone than a vitamin, and it plays a crucial role in neurotransmitter synthesis.
Physician’s Note: Do not start “mega-dosing” Vitamin D based on a hunch. It is a fat-soluble vitamin that can reach toxic levels. Get a blood test first to determine your baseline and allow your doctor to prescribe a clinical dose tailored to your needs.
3. Behavioral Activation
The urge to “hibernate” is strong, but social isolation and physical inactivity actually worsen the neurochemical imbalance. Even a 10-minute walk during the peak daylight hours (typically between 11:00 AM and 1:00 PM) can be more effective than a nap.
When to Seek Help
If your low mood is interfering with your ability to work, maintain relationships, or if you feel a sense of hopelessness, it is time to move beyond self-care. We can explore options like Cognitive Behavioral Therapy (CBT-SAD) or temporary pharmacological support to get you through to the spring.