Seasonal Affective Disorder

Seasonal affective disorder (SAD) is a type of depression that comes and goes with the seasons. Most commonly, it starts in late autumn or winter and eases during spring and summer. Some people have the opposite pattern — episodes in spring or summer — but this is less common. SAD is more common in regions far from the equator where daylight hours change dramatically. In India, SAD is less prevalent than in Europe or North America, but it does occur — particularly in northern states with darker winters, and in people with low vitamin D levels (which are common across India due to limited sunlight exposure even in sunny regions).

Symptoms may include:

• Sadness
• Gloomy outlook
• Feeling hopeless, worthless, or irritable
• Loss of interest or pleasure in activities you used to enjoy
• Low energy
• Trouble sleeping, or sleeping too much
• Carbohydrate cravings and weight gain
• Thoughts of death or suicide

SAD is more common in women, in younger adults, and in people who live far from the equator. Family history of depression or SAD raises the risk.

The exact cause is not known. People with SAD may have changes in serotonin (a mood-related brain chemical), make more melatonin (a hormone that regulates sleep), and have lower vitamin D. In India, checking and treating vitamin D deficiency is often a first step because the baseline deficiency rate is high.

The main treatment for SAD is light therapy — sitting in front of a bright light-therapy box each morning to replace the missed sunshine. Some people respond to light therapy alone; others need additional help. Antidepressant medicines and talk therapy (particularly cognitive behavioural therapy for SAD) are also effective, alone or with light therapy. Regular outdoor activity during daylight hours, a consistent sleep schedule, exercise, and yoga-based relaxation practices can all help.