Seasonal Affective Disorder (SAD): Why You May Feel Depressed in Winter

What is Seasonal Affective Disorder?

Seasonal Affective Disorder, or ‘SAD’ (what a fitting acronym!), is a type of depression that follows a seasonal pattern. SAD is known to most commonly present during late autumn or winter before subsiding in the months of spring and summer, though can also appear during the warmer seasons [1]. It is clinically recognised as a subtype of Major Depressive Disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). For this reason, it can often be colloquially referred to as Seasonal Depression. 

People with SAD experience many of the same symptoms as depression, but these symptoms tend to return at the same time each year, often when daylight hours decrease.

Why Do People Feel More Depressed in Winter?

Have you ever noticed your mood dropping as the weather gets colder or darker? You’re not alone. Many people report feeling more fatigued, flat, or withdrawn during winter.

SAD is believed to be precipitated by multiple different factors, including reduced exposure to sunlight, shorter days contributing to changes in people’s sleep-wake cycles, as well as other related hormonal shifts that can occur following these environmental changes [2].

Reduced Sunlight Exposure

Shorter days and less sunlight can disrupt your brain’s regulation of mood-related chemicals. 

Circadian Rhythm Changes

Seasonal shifts in daylight can affect your sleep-wake cycle (circadian rhythm), leading to fatigue, low energy, and difficulty concentrating.

Hormonal Changes

Changes in melatonin levels (which regulate sleep) may contribute to increased sleepiness and low mood during winter months.

How Common is Seasonal Affective Disorder in Australia?

Research shows that SAD is more common in regions further from the equator, where there is greater variation in daylight hours between seasons.

Research shows that while SAD can appear anywhere and at any time, its prevalence is greater in countries further from the equator and with high level variation in daylight hours between summer and winter, such as those in the Nordic region [3]. 

Although Australia generally has milder seasonal variation than some countries, people in southern regions like Victoria can still experience noticeable seasonal mood changes. This highlights the important role sunlight plays in both the onset and persistence of seasonal mood changes.

Signs and Symptoms of Seasonal Affective Disorder

Common symptoms of SAD include:

• Frequent low mood, feelings of sadness or hopelessness
• Chronic fatigue and low energy
• Loss of interest in activities you normally enjoy
• Significant changes to eating or sleeping habits
• Increased brain fog, feeling mentally sluggish or finding it harder to concentrate
• Increased thoughts of self-harm or suicide

If these symptoms occur regularly during the same season each year, it may indicate Seasonal Affective Disorder.

When to Seek Support

If seasonal changes are significantly affecting your mood, energy, or daily functioning, it may be helpful to speak with a psychologist.

At Q Psychology, our clinicians support individuals across Melbourne (Carlton & St Kilda) and Geelong with evidence-based approaches to managing depression, including seasonal patterns.

Treatment Options for Seasonal Affective Disorder

Effective treatments for SAD may include:

Psychological Therapy

Evidence-based therapies such as Cognitive Behavioural Therapy (CBT) can help address negative thinking patterns and behavioural withdrawal.

Exposure to daylight

Exposure to bright light at specific times of day may help regulate circadian rhythms and improve mood. Try to spend a minimum of 20-30 minutes outside getting sun exposure. Even on cloudy or overcast days, getting outside and experiencing natural light can have a positive impact on your wellbeing.

Lifestyle Adjustments

Stay active by walking, cycling, dancing, or try any other activity you like to raise endorphins and improve mood. Outdoor exercise during the day can also help increase natural light exposure.

Eat a varied diet by focusing on eating a wide range of whole foods to naturally meet your body’s nutritional needs. If regular sun exposure is limited, consider a vitamin D supplement to support your intake of this.

Staying socially engaged and connected with important people in your life plays a significant role in maintaining good mental health. You may also like to try joining clubs or group activities that match your interests, to help build and maintain meaningful connections.

Getting Help for Seasonal Affective Disorder in Melbourne and Geelong

If you’re noticing a pattern of low mood during winter, you don’t have to manage it alone. Seeking support early can help reduce the severity of symptoms and improve your overall quality of life.

Book an appointment with a psychologist at Q Psychology to explore personalised, supportive strategies for managing seasonal affective disorder.

References 

1. Kasof, J. (2009). Cultural variation in seasonal depression: cross-national differences in winter versus summer patterns of seasonal affective disorder. Journal of Affective Disorders, 115(1-2), 79-86.
2. Dollish, H. K., Tsyglakova, M., & McClung, C. A. (2024). Circadian rhythms and mood disorders: Time to see the light. Neuron, 112(1), 25-40.
3. Kim, K., Kim, J., Jung, S., Kim, H. W., Kim, H. S., Son, E., ... & Kim, Y. H. (2025). Global prevalence of seasonal affective disorder by latitude: A systematic review and meta-analysis. Journal of Affective Disorders, 390, 119807.

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