Seasonal Depression: Why Mood Can Drop During Certain Times of the Year
Have you ever felt low on a cloudy or cold morning? It feels like you have no energy to get through the day or no reason to feel happy at all.
Seasonal depression is a real, clinical condition, also known as Seasonal Affective Disorder (SAD). It is normal to feel gloomy on a dark morning or experience ‘winter blues’, but SAD is more intense and serious, with symptoms that can significantly affect mood, energy, sleep, and daily functioning. It is a type of depression that occurs at specific times of the year, most often in autumn and winter when daylight hours are limited.
Seasonal Affective Disorder is a recurrent depressive pattern linked to seasonal changes. The characteristic feature of this type of depression is that symptoms appear only during autumn or winter, and the person can function as their usual self during the rest of the months. A rare “summer-onset” form also exists, with symptoms appearing in warmer months with longer days.
Symptoms of Seasonal Affective Disorder (SAD)
Symptoms could vary by season, but winter-pattern SAD is most recognized.
Winter-pattern SAD
Persistent low mood, sadness, or hopelessness
Loss of interest or pleasure in usual activities (anhedonia)
Low energy, fatigue, and feeling sluggish
Oversleeping (hypersomnia) and difficulty waking up
Increased appetite, especially carbohydrate cravings, sometimes with weight gain
Difficulty concentrating, impaired decision making, slowed thinking, or “brain fog”
Social withdrawal and reduced motivation to carry out tasks
In severe cases, feelings of worthlessness, guilt, or suicidal thoughts
Summer-pattern SAD (less common)
Why the Mood Drops: Causes of Seasonal Affective Disorder
The exact cause of Seasonal Affective Disorder isn’t fully understood, but it is believed that
reduced sunlight is the central trigger. Several biological pathways are involved:
Circadian rhythm disruption-
Shorter days and less morning light can shift your internal body clock, disrupting sleep–wake cycles and daily energy patterns.
Serotonin changes-
Serotonin is a neurotransmitter that helps regulate mood. Sunlight influences the production of this neurotransmitter. During winter, the amount of sunlight received is less, which leads to lower serotonin activity, increasing depression risk.
Melatonin imbalance-
Darkness stimulates melatonin (the sleep hormone). Longer winter nights can raise melatonin levels during the day, causing sleepiness and lethargy.
Vitamin D and lifestyle factors-
Recent research has been focusing on the link between Vitamin D deficiency and the possible risk of developing depression. Lower sunlight can reduce vitamin D, and colder weather may limit outdoor activity and social contact, resulting in mood symptoms.
While the exact causes are unknown, these changes can make the nervous system “mismatched” to winter conditions, especially for people who spend most daylight hours indoors.
When Should I Seek Help for Seasonal Affective Disorder?
SAD is diagnosed when depressive episodes follow a seasonal pattern for at least two consecutive years, with full remission in other seasons, and when symptoms cause significant distress or impairment. If seasonal depression symptoms, low mood, loss of interest, sleep/appetite changes, or suicidal thoughts persist for more than two weeks, it’s important to consult a clinician or mental health professional.
If seasonal mood changes are affecting your daily life, online counselling can also provide a convenient way to speak with a mental health professional. For Malayalis looking for culturally familiar support, speaking with a Malayali psychologist through online therapy can make professional support more accessible.
Treatment of Seasonal Affective Disorder
Effective treatments combine light-based, psychological, lifestyle, and medical approaches.
Light therapy (first-line for winter SAD)-
Bright light therapy is the most commonly used, evidence-based treatment for winter-pattern SAD. A light box emitting 10,000 lux of bright, white light (UV-filtered) is used for 20–30 minutes each morning, ideally within an hour of waking. This is because early morning light helps reset circadian rhythms, suppress excess melatonin, and support healthier serotonin function. It is an effective option, as many people report improvement within 1–2 weeks, and continued daily use through the high-risk months is often recommended.
Psychotherapy-
Cognitive Behavioral Therapy is the therapeutic option for SAD (CBT-SAD). It helps identify and challenge negative thought patterns and behaviors that worsen in certain seasons. It can be as effective as light therapy and may provide longer-lasting benefits.
Medication-
Medications for moderate to severe SAD include antidepressants, particularly SSRIs, prescribed sometimes alongside light therapy. Medications should only be taken on the recommendation of a clinician.
Lifestyle changes-
Certain lifestyle changes could be made to support medical treatments and reduce symptom severity:
Maximize daylight exposure- You can spend time outdoors in the morning, even on cloudy days, because outdoor light is brighter than indoor lighting.
Regular physical activity- Exercise releases endorphins or ‘happy hormones’, boosts energy, and improves sleep quality.
Sleep hygiene- Maintain sleep hygiene by ensuring consistent sleep and wake times, limiting late-night screens and caffeine consumption.
Balanced diet- Practice having a balanced diet, emphasizing proteins, fiber, and healthy fats to stabilize energy. Avoid excessive refined carbs that can worsen mood swings.
Social connection- Plan regular meet-ups with friends, family, or support groups to counter isolation and loneliness.
Vitamin D- Get a blood test to determine Vitamin D levels. If deficient, supplementation under medical guidance may help, though evidence is mixed.
Prevention and Long-term Management of Seasonal Affective Disorder
If you have a history of SAD, starting light therapy and lifestyle measures before symptoms typically begin, such as in early autumn can prevent or blunt episodes. Starting a mood and sleep diary across seasons can help you and your clinician spot patterns and adjust treatment timing.
Seek immediate help in cases when you feel extreme mood disturbances or suicidal thoughts.
Seasons will change,
But Koott will always be by your side.
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