Seasonal Affective Disorder (SAD) is a type of depression that occurs at a specific time of year, usually during the autumn and winter months when there is less sunlight. It is sometimes referred to as “winter depression” or “winter blues.”


  1. Low energy: Individuals with SAD often feel lethargic and lack motivation.
  2. Changes in sleep patterns: SAD can lead to oversleeping or difficulty sleeping.
  3. Weight gain: Increased appetite, particularly for carbohydrates, is a common symptom.
  4. Difficulty concentrating: People with SAD may experience difficulties in focusing and making decisions.
  5. Loss of interest or pleasure in activities: Individuals may lose interest in activities they once enjoyed.


The exact cause of SAD is not known, but it is thought to be related to changes in sunlight exposure, which can affect the body’s internal clock (circadian rhythm) and lead to disruptions in melatonin and serotonin levels. Reduced sunlight exposure may also result in a deficiency of vitamin D, which could contribute to the symptoms.

Support and Treatment

Light therapy (phototherapy) is a common treatment for SAD. This involves exposure to a bright light that mimics natural sunlight. Other treatments may include psychotherapy, medication, and lifestyle changes.

It’s important to note that SAD is a recognised medical condition, and if you are experiencing symptoms, you should seek professional help for an accurate diagnosis and appropriate treatment.

Further Advice

Seasonal affective disorder (SAD) – NHS website