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Seasonal Affective Disorder (SAD)

a type of depression that is linked to seasonal changes and can negatively affect your day-to-day life

Seasonal Affective Disorder, commonly known as SAD, is a type of depression associated with seasonal changes. It differs from fleeting moments of sadness as it has a long-lasting effect on one’s daily life.

SAD is more common than you might think, affecting roughly 2 million people in the UK alone. 

Although SAD is usually linked to the winter season, it is essential to note that some people may experience its effects at any time. The winter season poses unique challenges, with shorter daylight hours and limited exposure to sunlight. In contrast, the summer season, with increased light, warmth, and humidity, may make some individuals more vulnerable to the onset of SAD. 

Regardless of the season, SAD has symptoms that closely resemble those associated with depression

Common myths about SAD

SAD is just the “Winter Blues” 

SAD is often seen as a mere case of “winter blues” that everyone experiences. It’s a clinically recognised form of depression with distinct symptoms and a profound impact on one’s daily life.

SAD only affects women

20% of SAD cases occur in men. The disruption of the circadian rhythm may play a role in the higher risk for women because of its impact on female hormones.

sunshine/light alone can cure SAD 

Whilst sunlight exposure can help mitigate SAD symptoms, it’s not a standalone cure. Effective management often involves a combination of light therapy, counselling and lifestyle adjustments. 


One big sign of SAD is feeling incredibly low on energy. It’s like a constant tiredness that doesn’t seem to go away, even if you’ve had a good night’s sleep. Everyday activities might feel like a real struggle.

Now, your sleep patterns can get pretty wonky. If you have winter SAD, you might find yourself sleeping way more than usual or having a hard time getting out of bed in the morning. For those with summer SAD, it’s the opposite – insomnia or frequently waking up in the middle of the night.

Focusing on tasks or making decisions can become a real challenge. Heightened irritability, agitation and appetite shifts (cravings or loss) are other key symptoms. You might feel anxious, really down, or have a constant sense of despair. Self-esteem can take a hit, and you might carry around feelings of guilt or even have thoughts about harming yourself.

Social withdrawal, unexplained physical discomfort like pain in joints and changes in your libido join the mix.

Causes of SAD 

The exact cause of SAD is not fully understood, but several factors are believed to contribute to its development.

Biological clock disruption

SAD is thought to be linked to disruptions in the body’s internal biological clock, also known as the circadian rhythm. Seasonal changes in light exposure can affect this internal clock, leading to mood disturbances. 

Reduced sunlight (winter SAD)

Sunlight exposure helps regulate melatonin (which affects sleep) and serotonin (which affects mood), and the decrease in sunlight during winter may lead to imbalances that contribute to SAD. Most recent studies suggest that inadequate exposure to daylight and excessive exposure to artificial light during nighttime can increase the risk of developing symptoms of mental illness and self-harm.

Increased sunlight (summer SAD)

While most people find increased sunlight invigorating, some individuals may have heightened sensitivity to light, causing discomfort and contributing to developing symptoms of summer SAD.

Hormonal changes

Seasonal variations can affect the production and release of hormones in the body. For example, changes in light exposure can influence the production of melatonin and serotonin. A drop in serotonin levels is associated with depressive symptoms. It’s believed that reduced sunlight exposure can decrease serotonin production, contributing to SAD. Melatonin, a hormone that regulates sleep patterns, is produced in higher amounts in darker conditions. The longer nights of winter may lead to an overproduction of melatonin, causing fatigue and other SAD symptoms. 

Genetic factors

Family history and genetics may also play a role in the development of SAD. If you have a family member with a history of SAD, other types of depression and mood disorders, you may be more genetically predisposed to developing SAD. 

Psychological factors

Past experiences of trauma, stress, or significant life changes may make people more vulnerable to SAD. Additionally, existing mental health conditions, such as depression or bipolar, can interact with seasonal changes and exacerbate symptoms of SAD.

In partnership with clinicians, University of Glasgow and University of Edinburgh have created an online module ‘Living Life to the Full’ to help people who are experiencing SAD. It’s currently used within the NHS and has been shown on BBC Scotland and STV.

You can read more about the online module here. 

Tips for managing SAD

Managing Seasonal Affective Disorder (SAD) involves a combination of lifestyle changes, light therapy, psychotherapy, medication and self-care strategies. Here are some practical ways to manage SAD:

Embrace natural light 

Spend time outdoors during daylight hours, especially in the morning, to maximise exposure to natural sunlight. You can also consider using a SAD lamp, a special light therapy device that mimics natural light, which can help regulate your body’s internal clock and improve your mood.  

Nutritious diet

Maintain a well-balanced and nutritious diet rich in fruits, vegetables, and whole grains. These foods provide essential nutrients that can help stabilise your mood and energy levels, which is especially important for managing SAD. At the same time, try to avoid excessive consumption of sugary or processed foods. 

Stay active and social

Engage in social activities, whether it’s meeting friends, participating in hobbies, or volunteering. Regular physical activity can also boost your mood, so consider outdoor walks or exercise classes with a social aspect. 

Practice mindfulness and relaxation

Mindfulness techniques, meditation, and relaxation exercises can help manage stress and alleviate SAD symptoms. Find a practice that works for you and integrate it into your daily routine. 

Maintain a consistent routine

Establish a daily schedule that includes regular sleep, meals, and activity times. A consistent routine can help stabilise your circadian rhythm and provide a sense of structure and predictability. 

Professional support 

If needed, work with a mental health professional, such as a psychologist, psychiatrist, or counsellor, to develop coping strategies and techniques that can help manage symptoms. These professionals create a safe space for individuals to express their feelings, fears, and struggles, promoting understanding and providing effective tools to manage symptoms. This may include therapies like cognitive-behavioural therapy (CBT) or other personalised treatment plans. Whether through one-on-one therapy sessions or group support, seeking help from a mental health professional can be a valuable support in managing SAD.


If you or anyone you know requires support, our Advice and Support Service is open Monday to Friday, 10 am to 4 pm, where advisers can signpost you to local support that fits your needs, including our Change Mental Health services. We offer initial advice on money worries and help to deal with emergencies.

Contact 0808 8010 515, email us at or fill out the enquiry form on the Advice and Support Service page.

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