Why winter triggers seasonal depression and what works best to ease SAD

Winter blues are common, but SAD is a recurring depressive condition that needs attention. From overlooked symptoms to light therapy and sleep routines, here's what experts recommend

As temperatures dip and daylight hours shrink, many people notice a shift in their mood, a little more fatigue, a little less motivation. But for some, these changes signal something more serious. Seasonal Affective Disorder (SAD) or seasonal depression is a recurring form of depression that appears in the colder months and lifts with spring. Experts say early recognition and simple lifestyle adjustments can make a significant difference.

 

“Seasonal affective disorder is a type of recurrent depressive episode with a seasonal pattern, typically seen during the fall and winter months, with periods of full improvement in the spring and summer,” explains Dr Nikita Bhati, Senior Clinical Psychologist, Samarpan Health.

 

The early signs people often miss

 

SAD doesn’t begin abruptly. Its symptoms usually build gradually through winter. Common, easily overlooked early signs include:

• Increased tiredness despite sleeping more
• Low energy and reduced motivation
• Mild mood dips
• Social withdrawal
• Difficulty concentrating

 

These can be mistaken for burnout or routine low mood. “Some people can have a milder form known as subsyndromal SAD,” says Dr Bhati, noting that symptoms tend to worsen as the season progresses.

 

Why winter affects the brain

 

• Reduced sunlight disrupts the body’s internal clock, mood pathways and sleep cycles
• Shorter days may upset serotonin levels, a key mood-regulating chemical, while also affecting melatonin, which manages sleep
• Lower vitamin D levels in winter are also associated with worsened mood and fatigue.

 

Who is most at risk?

 

People living farther from the equator face higher SAD risk due to long, dark winters.

Women who have had a prior history of mood disorder are five times more likely to develop SAD, notes Dr Bhati.

Young adults aged 18–30 may also be more vulnerable, possibly because irregular sleep schedules and lifestyle patterns can aggravate seasonal mood shifts.

 

When to seek help?

 

If low mood persists for days, disrupts work or relationships, or leads to hopelessness, substance use or suicidal thoughts, immediate professional support is essential. “SAD can be a potentially serious condition if left untreated,” she cautions.

Early recognition, structured routines and timely care can ensure the season feels lighter, even if some days don’t.

 

How to prevent or ease SAD

 

Dr Bhati recommends a multi-pronged approach, with these evidence-based strategies:

 

• Bright light therapy: Morning exposure to a medically approved light box remains one of the most effective interventions.
• Movement in daylight: Outdoor walks or exercise during daylight hours can boost serotonin and stabilise circadian rhythms.
• Consistent sleep cycles: Avoid oversleeping, irregular naps and late-night screen exposure to prevent melatonin disruption.
• Balanced diet & vitamin D: Supplement only on medical advice, after checking levels.
• Cognitive Behaviour Therapy (CBT): Practised before symptoms peak, CBT equips individuals with skills to manage seasonal triggers and prevent relapse.

 

“Combining these treatments is found to be highly effective in treating SAD,” says Dr Bhati.   

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This report is for informational purposes only and is not a substitute for professional medical advice.