Seasonal Affective Disorder (SAD) is a type of depression that follows a seasonal pattern, typically occurring during the autumn and winter months when daylight hours are shorter and resolving in spring or summer

The condition is believed to result from changes in light exposure, which disrupt the body’s circadian rhythm and alter the production of mood-regulating hormones, particularly melatonin and serotonin.

Common Symptoms

Symptoms often begin in late autumn or early winter and improve in spring, although some people experience the reverse pattern (summer SAD).

• Persistent low mood or sadness

• Loss of interest or pleasure in usual activities

• Fatigue or low energy, even after sleeping

• Increased sleep (hypersomnia) and difficulty getting up

• Increased appetite, particularly for carbohydrates and sweet foods

• Weight gain

• Difficulty concentrating

• Feelings of hopelessness, guilt, or worthlessness

• Social withdrawal (“hibernating” behaviour)

If symptoms are severe or last for most of the day, nearly every day, for two weeks or more, professional support is recommended.

Treatment Options

Treatment for SAD is similar to that for other forms of depression, but tailored to its seasonal nature. Evidence-based approaches include:

Light Therapy (Phototherapy)

The most common first-line treatment. Uses a light box (10,000 lux) for 20–30 minutes each morning to simulate natural sunlight. Helps regulate melatonin and serotonin levels.

Talking Therapies

Cognitive Behavioural Therapy (CBT), especially CBT for SAD (CBT-SAD), helps people identify and manage negative thought patterns and behaviours linked to the season.

Medication

Antidepressants, particularly SSRIs (e.g., sertraline, fluoxetine), may be prescribed when symptoms are moderate to severe or persist despite other treatments.

Self-Help and Prevention Strategies. Even small daily habits can help ease symptoms or prevent recurrence:

• Increase Natural Light Exposure - Spend time outdoors daily, especially in the morning. Keep curtains open and sit near windows. Trim hedges or move furniture to maximise sunlight at home or work.

• Stay Active - Physical activity boosts serotonin and endorphins. Even gentle movement (walking, stretching) has benefits.

• Maintain a Regular Routine - Consistent sleep and wake times help regulate circadian rhythms. Eat balanced meals and limit your intake of excessive sugar and alcohol.

• Stay Connected - Social interaction counters isolation and improves mood. Join groups, talk to colleagues, or connect virtually if going out is hard.

• Practise Mindfulness and Self-Compassion - Meditation, breathing exercises, or journaling can reduce stress. Recognise that rest and lower energy are natural in winter — be kind to yourself.

• Plan Ahead - If SAD recurs annually, start light therapy or counselling in early autumn before symptoms begin.