Why You Feel Down Every Winter - Seasonal Depression (SAD) and How to Fight It

About a 3 min read.

What Is Seasonal Affective Disorder (SAD)?

Seasonal Affective Disorder (SAD) is a type of depression that recurs during specific seasons. The most common form is the autumn-winter type, with symptoms appearing around October to November as daylight hours shorten, then naturally improving in spring. In Nordic countries, roughly 10% of the population is estimated to experience SAD, and in Japan the prevalence tends to be higher in regions at higher latitudes.

SAD is not simply "feeling a bit low in winter." In the DSM-5, it is classified as Major Depressive Disorder with a seasonal pattern specifier - a legitimate psychiatric condition.

Symptoms of SAD

Typical symptoms include persistent low mood, loss of interest or pleasure, hypersomnia (feeling sleepy no matter how much you sleep), overeating (especially carbohydrate cravings), weight gain, difficulty concentrating, and social withdrawal. While typical depression often involves insomnia and appetite loss, SAD is characterized by hypersomnia and overeating.

The Mechanisms Behind SAD

Daylight and Serotonin

Sunlight promotes the production of serotonin, a neurotransmitter that stabilizes mood. When daylight hours decrease in winter, serotonin production drops, leading to low mood.

Excess Melatonin Secretion

Dark environments increase the secretion of melatonin (the sleep hormone). The long winter nights trigger excess melatonin production, causing hypersomnia and fatigue.

Disrupted Body Clock

Changes in daylight hours disrupt the circadian rhythm (body clock), affecting sleep-wake cycles, hormone secretion, and body temperature regulation. (Books on seasonal mental health can help you learn more)

Coping Strategies

1. Light Therapy

The first-line treatment for SAD is light therapy. A 10,000-lux bright light therapy device is used for 30 minutes after waking in the morning. It is effective for roughly 60-80% of patients, with improvement typically seen within one to two weeks. Light therapy devices are commercially available as medical devices and can be used at home.

2. Morning Sunlight Exposure

Even without a light therapy device, exposure to natural morning light can be beneficial. Go outside within 30 minutes of waking and spend 15-30 minutes in sunlight. Even on cloudy days, outdoor light levels are more than 10 times greater than indoors, so it still helps.

3. Exercise

Aerobic exercise promotes the release of serotonin and endorphins, alleviating SAD symptoms. Moderate-intensity exercise (walking, jogging, swimming) for about 30 minutes, three to five times a week, is recommended. Exercising outdoors is especially effective because it combines the benefits of sunlight exposure and physical activity.

4. Medication

For severe symptoms, SSRIs (selective serotonin reuptake inhibitors) may be prescribed. Bupropion is the only medication FDA-approved for preventive use in SAD. It is typically started before symptoms appear in autumn and discontinued in spring. (Books on mental health are also a useful reference)

Summary

Feeling down in winter is not "just in your head" - it is a physiological response to reduced daylight. Light therapy, morning sunlight exposure, exercise, and medication when needed. Knowing these coping strategies gives you the strength to get through each winter.