Seasonal Affective Disorder (SAD)
Seasonal depression is a real physiological response to lost light. We prepare before the season turns — light, rhythm, vitamin D, thyroid, blood sugar, and acupuncture.
When the Light Goes, So Does Something in You
Seasonal affective disorder is a form of depression that arrives with the darker months and lifts as the light returns. In a place like the Pacific Northwest, where the winters are long and gray, it is not a rare problem — it is one of the most relatable conditions we treat. The low mood, the heaviness, the carbohydrate cravings, and the pull toward hibernation are the body responding, accurately, to a genuine drop in light.
This is the GoodMedizen lens. The body is not malfunctioning. It is responding accurately to the information it is being given. Change the inputs and the response begins to change with them.
What SAD Actually Is
It is a recurrent, seasonal pattern of depression, most often in fall and winter, driven largely by reduced sunlight. The shortened days disrupt the body’s internal clock, shift melatonin and serotonin signaling, and lower vitamin D. A milder version, often called the winter blues, is more widespread still.
This is not a character flaw or a failure of willpower. It is a measurable physiological response to light, circadian rhythm, and the neurochemistry they govern.
What Is Actually Driving It
- Reduced sunlight and its effect on the circadian clock and melatonin timing
- Disrupted serotonin signaling, which light helps regulate
- Low vitamin D, nearly universal in northern winters
- Blood sugar instability, worsened by the carbohydrate cravings SAD brings
- An underactive thyroid, whose symptoms overlap heavily with winter depression
- Sleep and rhythm disruption from short, dark days
- An already-taxed stress system
Why It Deserves Real Attention
SAD is often waved off as something to push through, yet it meaningfully affects work, relationships, and health every year it goes untreated. It is also highly responsive to the right combination of light, rhythm, nutrients, and support.
Signs and Patterns
- Low mood that tracks with the seasons
- Heavy fatigue and oversleeping
- Carbohydrate and sugar cravings, often with weight gain
- Loss of interest and motivation
- Difficulty concentrating
- Social withdrawal
- A reliable lifting of all of it in spring
If low mood deepens into hopelessness or thoughts of self-harm, that is a reason to reach out to a physician or crisis support promptly, and we coordinate care in those situations.
How We Look at It — The Testing
- Vitamin D — 25-OH measured and brought to roughly 60 to 70, since it is both low in winter and tied to mood
- Thyroid — a full panel with antibodies, because hypothyroid symptoms mirror winter depression almost exactly, and we often see symptoms at a TSH as low as 1.75
- Blood sugar — fasting glucose, HbA1c, and where useful fasting insulin, since the carbohydrate cravings of SAD destabilize it
- Foundational — B12 with homocysteine and MMA, a complete iron and ferritin profile (low iron mimics depression and fatigue), RBC magnesium, and a CBC with differential
Broad baseline labs do not have to be expensive. Services such as Function Health let patients obtain large workups affordably, and we have no financial stake in that — we would rather your budget go toward care than toward lab markups. For targeted functional testing we order through Diagnostic Solutions (GI-MAP) for the microbiome, Quicksilver Scientific for heavy metals, and through Fullscript where it serves you best, with every marker read against optimal ranges rather than the wide line between “normal” and “abnormal.”
The Chinese Medicine Lens
Chinese medicine sees the winter pattern as a combination of stagnation and depletion. The lack of light and movement allows qi to stagnate, particularly the Liver qi that governs the smooth flow of mood, while the cold, dark season draws on the body’s deepest reserves, the yang warmth of the Kidney and Spleen that keeps energy and spirits up. The result is the familiar heaviness, low drive, and dampened spirit.
Treatment moves the stagnation and warms and strengthens the reserves, which is why people often describe acupuncture in winter as lifting a fog.
How Acupuncture and Functional Medicine Help
Acupuncture has a regulating effect on mood and the stress response, supports sleep and circadian rhythm, and is used to move stagnation and rebuild the warmth that winter depletes.
The functional work pairs naturally with the proven seasonal tools: morning light exposure or light-box therapy, a steadied circadian rhythm, vitamin D repletion, blood sugar stability to blunt the cravings, and thyroid support where it is needed. Because SAD is predictable, starting before the season turns makes the biggest difference.
Care That Works With Your Other Providers
For depression that is severe, persistent, or includes thoughts of self-harm, care with a physician or mental health professional comes first, and we are glad to work alongside it. Acupuncture and functional medicine complement that care; they do not replace it.
Your Body Isn’t Broken
If you have spent years being told your labs look normal while you clearly do not feel normal, you have not been imagining it. With seasonal depression, the work is to support the body through the dark months and prepare before they arrive, not to white-knuckle through. Your body is not broken. The support has just been missing.
At GoodMedizen in downtown Seattle, we treat the system driving the condition, not only the symptoms it produces.