The Seasonal Depression Map

Late-fall onset, hypersomnia, hyperphagia, and the depression that tracks the calendar.

Seasonal depression — formally called Major Depressive Disorder with Seasonal Pattern, often abbreviated SAD — is a depression that tracks the calendar. Symptoms begin in late fall or early winter, peak in the darkest months, and remit in spring. The pattern is consistent year over year. For people with classic SAD, the cluster of symptoms is recognizable enough that they often know it’s coming before it arrives.

SAD has a specific feature profile that distinguishes it from year-round depression. Where typical depression often involves insomnia (early waking, trouble falling asleep) and appetite loss, SAD involves hypersomnia (sleeping much more than usual) and hyperphagia (eating more, especially carbohydrates). Energy is profoundly low. Social withdrawal is heavy. The cluster matches an evolutionary hibernation profile, which is part of why it's thought to track the light cycle.

This map shows the cluster as it actually appears: the seasonal onset, the sleep-and-eating shift, the carb cravings, the energy crash, the social withdrawal, and the light deprivation that drives it. Bright light therapy, vitamin D (when low), and standard antidepressants all have evidence. The treatment is well-known; the cluster is treatable. Recognizing the seasonal pattern is what gets people to the right treatment instead of generic care.

Tap any node to read the page on that experience.

Inside this cluster

The Seasonal Depression Map: a central node labeled Seasonal Depression connected to 8 elements — late-fall onset, hypersomnia (oversleeping), hyperphagia (overeating), carb cravings, energy crash, social withdrawal, light deprivation, and spring remission.

Late-fall onset — Symptoms begin in October or November and intensify through the dark months. The pattern is consistent year over year — that consistency is itself diagnostic.
Hypersomnia (oversleeping) — Sleeping ten or more hours and still feeling unrested. A defining feature of seasonal depression specifically; uncommon in other depression subtypes.
Hyperphagia (overeating) — Eating more than usual, with reduced satiety. Often paired with weight gain over the cold months and weight loss in spring.
Carb cravings — A specific subset of hyperphagia — strong cravings for bread, pasta, sweets. Theorized to reflect a serotonin-related drive that worsens in the dark.
Energy crash — A profound flattening of physical energy. Tasks that felt easy in summer feel disproportionate in winter, even controlling for sleep.
Social withdrawal — Withdrawal from social contact that often gets explained as "I just don't have the energy this time of year." Part of the cluster, not just the season.
Light deprivation — The likely upstream driver. Shorter days, less morning light, less daytime exposure. Targets the circadian and melatonin systems.
Spring remission — Symptoms lift, often suddenly, as days get longer. A diagnostic feature: the remission is reliable year after year, even without treatment changes.

Treatment that works on this cluster

Seasonal depression has more well-evidenced treatment options than most depression subtypes. Bright light therapy — 10,000 lux exposure for 20-30 minutes in the morning, started in early fall as a preventive measure or at symptom onset — has strong evidence and is often the first-line treatment. SSRIs (sertraline, fluoxetine) work and are used either continuously or just during the symptomatic months. Bupropion XL has FDA approval specifically for the prevention of seasonal depression and is started in early fall. Cognitive behavioral therapy adapted for SAD (CBT-SAD) has evidence for both treatment and prevention. Vitamin D supplementation is reasonable when blood levels are low, though the evidence for prevention with vitamin D alone is mixed. Many people use a combination — a light box plus a medication plus the schedule changes that come with knowing the season will be hard.

What people describe

One person describes the calendar. They had figured out by their late twenties that something happened to them in November. The first November they tracked it deliberately, the change started around the time the clocks went back. By the second week of November they were sleeping ten hours a night and craving pasta. By mid-December, they were genuinely depressed. The recognition that this was a pattern, not just "winter," was the thing that got them to a clinician. They’ve been on a light box every fall since.

Another describes the spring lift. They had been seriously depressed for four months. Without changing medication, therapy, or anything else, by the third week of March they noticed they were waking up before the alarm. By April, the depression was largely gone. They hadn’t done anything different — the days had gotten longer. Knowing that this was the seasonal pattern, and that the pattern would return in November, was both a relief and a new kind of work.

Why this cluster matters

Seasonal depression is often dismissed as "the winter blues" or treated as ordinary depression, both of which miss the specific cluster and the specific treatments that work on it. Naming the seasonal pattern unlocks bright light therapy, the prevention strategies that work when started in early fall, and the option of seasonal-only medication. People with classic SAD often respond very well to treatment when the cluster is recognized — and they can plan around the predictable timeline.

How this differs from adjacent clusters

Seasonal depression is often confused with the holiday stress that many people experience in November and December — financial pressure, family complications, social overload. Holiday stress is situational and resolves when the holiday season ends. Seasonal depression is biological and tracks the light cycle, not the calendar of holidays. People with both can have a particularly difficult December.

Seasonal depression also differs from circadian rhythm disorders, in which sleep timing is shifted (delayed sleep phase, advanced sleep phase) without the full depression cluster. Circadian rhythm disorders respond to light therapy too, but the underlying problem is different.

Finally, seasonal depression in the winter pattern is the well-known kind, but a smaller subset of people experience a summer-pattern variant — depression that peaks in the long, hot summer months, with insomnia and appetite loss instead of hypersomnia and hyperphagia. The summer pattern is less well-studied and may respond to different approaches, including air conditioning and reduced light exposure.

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