Do you struggle when the nights draw in and the days feel shorter? If your mood seems to dip every autumn and winter, you may be experiencing seasonal affective disorder (SAD).
SAD is a recognised form of depression linked to seasonal changes. While many people find winter more challenging, SAD goes beyond the ‘winter blues’ and can significantly affect your mood, energy and day-to-day life.
The good news is that effective treatment options are available. With the right support, many people are able to manage their symptoms and feel more like themselves again.
Book a mental health assessment to speak with a specialist.
Seasonal affective disorder (SAD) is a type of depression that follows a seasonal pattern. In the UK, symptoms usually begin in autumn or early winter when natural daylight decreases, and improve during spring and summer when daylight hours increase.
SAD is more common in countries further from the equator, where winter days are shorter and darker. It can affect adults of all ages but is reported most frequently in younger adults.
It’s important to recognise that SAD is more than simply feeling low during the winter months. It involves a recurring pattern of depressive symptoms that return at roughly the same time each year and interfere with mood, energy levels and daily functioning.
The defining feature of SAD is that symptoms follow a seasonal pattern, typically worsening during autumn and winter and improving in spring.
If these symptoms appear at the same time each year and begin to ease as the seasons change, it may indicate that you are experiencing SAD.
Many people notice their mood dips slightly during the darker months, sometimes referred to as the ‘winter blues’. Shorter days, colder weather and reduced sunlight can naturally make some people feel more tired or less motivated.
The key difference is how much symptoms affect daily life. The winter blues tend to be mild and manageable, allowing people to continue with their usual routines. SAD involves more persistent depressive symptoms that can significantly affect work, relationships, energy levels and overall functioning.
If you are unsure which you may be experiencing, speaking with a professional can help clarify your symptoms and guide you towards appropriate support.
Reduced daylight plays an important role in SAD. Natural light helps regulate biological systems that influence sleep, energy and mood. When daylight decreases, these systems can become disrupted.
Your circadian rhythm is your internal body clock. It uses light signals to regulate when you feel awake and when you feel sleepy. When days become shorter, this rhythm can become disrupted, leaving you feeling more tired, low in energy or flat in mood.
Sunlight helps regulate serotonin, a brain chemical involved in mood regulation. Reduced daylight may lower serotonin levels, which can contribute to depressive symptoms.
Melatonin controls the body’s sleep cycle. During darker months, the body may produce more melatonin than usual, which can make you feel sleepier, sluggish or less alert during the day.
The hypothalamus is an area of the brain involved in regulating sleep, appetite and mood. Reduced sunlight can influence how it functions, which in turn affects hormones linked to energy and emotional wellbeing.
Together, these biological changes help explain why some people experience a seasonal pattern of low mood and reduced energy.
There is no single cause of SAD, but several factors can increase the likelihood of developing it.
If you already experience depression, symptoms may become more noticeable or difficult to manage during winter.
SAD is a treatable condition. Many people experience significant improvement through a combination of therapy, lifestyle adjustments and, in some cases, medication. Treatment is tailored to symptom severity, medical history and personal preferences.
Light therapy involves sitting near a medically approved light box that produces a bright light similar to natural daylight. It is typically used for around 30 minutes each morning, often shortly after waking.
Exposure to this light can help regulate the body’s internal clock and support brain chemicals involved in mood regulation. Some people notice improvements within one to two weeks.
Some individuals also use dawn simulators, which gradually brighten the bedroom in the morning to mimic a natural sunrise. These devices can help support a healthier sleep–wake cycle during darker months.
It is important to use a clinically recommended light box and follow the safety instructions. If you have an eye condition or bipolar disorder, speak with a healthcare professional before starting light therapy.
Cognitive behavioural therapy (CBT) is an evidence-based treatment for SAD. It helps you understand how thoughts, behaviours and mood influence each other.
CBT may help you:
Therapy can be particularly helpful for people who experience SAD every year.
For moderate to severe SAD, antidepressants such as selective serotonin reuptake inhibitors (SSRIs) may be recommended. These medications increase serotonin availability in the brain, which supports mood regulation.
Sometimes medication may be started in autumn before symptoms fully develop and reviewed in spring as daylight increases. Medication decisions should always be made in consultation with a GP or psychiatrist, who can discuss potential benefits and side effects.
Lifestyle and self-care strategies
Small, consistent habits can support your wellbeing during the winter months:
These strategies are most effective when combined with professional support.
Consider seeking support if:
If you are in immediate danger or feel unable to stay safe, call 999 or go to your nearest A&E department. You can also contact NHS 111 for urgent mental health advice.
Early intervention can help prevent symptoms from becoming more severe.
At Priory, we provide personalised, evidence-based treatment for seasonal affective disorder as part of our wider depression treatment services.
Your care begins with a comprehensive mental health assessment. From there, we create a tailored treatment plan that may include:
Our multidisciplinary teams include psychiatrists, therapists and mental health professionals who work together to support your treatment and wellbeing.
Book a mental health assessment today to explore the most suitable treatment options for you.
Seasonal affective disorder is common, particularly in northern climates, but it does not have to define your winters.
With appropriate treatment and support, many people are able to manage their symptoms and improve their wellbeing during the darker months.
If you recognise these symptoms in yourself or someone you care about, speaking with a professional can help you understand what support may be helpful.
