Seasonal Affective Pattern

Winter low mood is shaped by light, circadian rhythm, the pineal gland, vitamin D, and brain chemistry. We use light, rhythm, nutrients, and nervous system work to carry you through darker months.

What you may be noticing

As days shorten, your energy drops. You sleep longer and still feel tired. You crave carbohydrates. Motivation fades, and you withdraw from people and activities. It lifts in spring, then returns the next fall.

If low mood includes thoughts of suicide or self-harm, call or text 988 in the United States, or seek emergency care.

Why it is rarely one thing

Seasonal affective disorder is a recognized pattern of depression that recurs with the seasons, most often in fall and winter, and it is more common at higher latitudes.

I think of light as the first macronutrient. Light entering the eyes travels through specialized retinal cells to the master clock in the hypothalamus, which sets the timing of cortisol, body temperature, and melatonin. The pineal gland acts as the timekeeper that translates light and darkness into hormonal rhythm. With less morning light, the clock can drift later, melatonin can extend into the morning, and serotonin signaling may decline. Bright evening screens compound the drift.

Because the brain is the master system, a misaligned clock ripples outward into blood sugar, appetite, thyroid signaling, immune function, and mood. Vitamin D, made in the skin with sunlight, falls in winter, though trials of vitamin D for seasonal depression have shown mixed results. Reduced movement and more time indoors add to the effect. This is a brain responding faithfully to changing light, and it responds just as faithfully when we give it better signals.

Bright light therapy has solid research support for seasonal depression. Timing and intensity matter, and it works best with guidance.

Patterns we look for

• Morning outdoor light and time outside.
• Evening screen and artificial light exposure.
• Sleep timing and circadian rhythm.
• Vitamin D status.
• Thyroid function and cortisol rhythm.
• Blood sugar and carbohydrate cravings.
• Omega-3, ferritin, and B12 status.
• Physical activity levels.
• Prior depression history.
• Bipolar patterns, which affect how light therapy is used.

How I evaluate it

The comprehensive functional neurological exam assesses autonomic balance, pupil responses to light, eye movements, and frontal lobe function, which reflect how the brain is adapting to seasonal change.

Functional labs may include vitamin D, a full thyroid panel, a cortisol rhythm, ferritin, B12, fasting glucose and insulin, and omega-3 index. A mood and sleep log across seasons helps confirm the pattern. I coordinate with your physician or counselor when depression is significant.

How we address it

1. Step outside for morning light soon after waking each day, even on cloudy days.
2. Use bright light therapy in the morning, with guidance on timing and safety, especially if bipolar disorder is possible.
3. Dim lights and screens in the evening so melatonin can rise on time.
4. Keep consistent wake times through winter.
5. Replete vitamin D and omega-3 fats where low, and stabilize blood sugar to ease cravings.
6. Use short morning activating and evening calming nervous system routines.
7. Move daily, ideally outdoors, and plan winter connection and meaning.
8. Begin these rhythms in early fall, before symptoms deepen.

Light is information for the brain. Give it clear signals, and your rhythm and mood can follow.

Book your Comprehensive Functional Medicine Eval/Neurological Exam today to discover what the contributing root causes are that are underlying your health concerns.