Seasonal Affective Disorder

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Other names for Seasonal Affective Disorder

Seasonal depression
Winter-onset depression
Light deficiency disorder

Synopsis of Seasonal Affective Disorder

Seasonal Affective Disorder (SAD) is a type of depression that occurs at specific times of the year, most commonly in the fall and winter months when daylight hours are shorter. It is linked to reduced sunlight exposure, which can disrupt circadian rhythms and lower serotonin and melatonin levels—neurochemicals vital to mood regulation and sleep. SAD leads to symptoms such as persistent low mood, fatigue, oversleeping, carbohydrate cravings, weight gain, and social withdrawal. A less common form, known as summer-pattern SAD, can cause anxiety and insomnia during warmer months. While SAD is more common in colder climates and higher latitudes, it is treatable with light exposure, supplementation, and lifestyle adjustments.

Types:

  • Winter-pattern SAD: Most common, with symptoms appearing in late fall or winter

  • Summer-pattern SAD: Less common, symptoms triggered by heat or extended daylight

Common Causes:

  • Decreased sunlight exposure leading to melatonin overproduction and serotonin deficiency

  • Disrupted circadian rhythms due to shorter days

  • Vitamin D deficiency during darker months

  • Genetic predisposition to mood disorders

  • Preexisting depression or bipolar disorder

Severity Causes:

  • Lack of morning light exposure or outdoor activity

  • Chronic stress, isolation, or poor sleep hygiene

  • Nutritional deficiencies (vitamin D, B vitamins, omega-3s)

  • Coexisting depression, anxiety, or hypothyroidism

When to See a Doctor:

  • Depressed mood that returns each year in a seasonal pattern

  • Sleep disturbances and fatigue interfering with daily function

  • Cravings, overeating, or significant weight changes

  • Suicidal thoughts or worsening depression

  • No improvement with light exposure or self-care efforts

Natural remedies for Seasonal Affective Disorder

Light therapy (phototherapy): Daily exposure to a 10,000-lux light box for 20–30 minutes in the morning can regulate circadian rhythms and boost serotonin. Most effective when started in early fall.

Vitamin D: Supports mood, immune function, and circadian regulation. Supplementation is often necessary during winter when sun exposure is minimal.

Omega-3 fatty acids: Improve serotonin signaling and reduce inflammation. Shown to alleviate depressive symptoms in some people with SAD.

Magnesium: Calms the nervous system, supports melatonin production, and helps regulate sleep and mood, especially during periods of low sunlight.

B-complex vitamins: B6, B12, and folate are vital for neurotransmitter synthesis. Deficiency is linked to mood disorders and poor stress tolerance.

GABA: Helps reduce anxiety and promote calm in winter-pattern SAD, particularly when sleep disturbances are present.

Exercise: Regular physical activity boosts endorphins and helps reset circadian rhythms, improving mood and energy levels.

Avoid refined sugar and excess caffeine: These can worsen energy crashes, irritability, and sleep disturbances associated with SAD.