What is seasonal affective disorder (SAD)?

SAD is a type of depression that has a seasonal pattern. The episodes of depression tend to occur at the same time each year, usually during the winter. The symptoms often begin in the autumn as the days start getting shorter, and are usually most severe during December, January, and February.

According to the NHS, symptoms of SAD can include:

  • A persistent low mood
  • A loss of pleasure or interest in normal everyday activities
  • Irritability
  • Feeling of despair, guilt, and worthlessness
  • Lacking energy and sleepy during the day
  • Sleeping for longer than normal
  • Difficulty concentrating

For some people, these symptoms can be severe and have a significant impact on their day-to-day activities.


What causes SAD?

The NHS has explained that the exact cause of SAD is not fully understood, but it’s often linked to reduced exposure to sunlight during the shorter autumn and winter days. The main theory is that a part of the brain called the hypothalamus might stop working due to the lack of sunlight, which may affect the:

  • Production of melatonin: Melatonin is a hormone that makes you feel sleepy; in people with SAD, the body may produce it at higher-than-usual levels.
  • Production of serotonin: The hormone serotonin affects your mood, appetite, and sleep; a lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression.
  • Body’s internal clock (circadian rhythm): Sunlight is used by your body to time various important functions, such as when you wake up, so a decrease in light levels during the winter may disrupt your body clock and lead to symptoms of SAD.


5 self-help tips to help you manage SAD:

Living with SAD is challenging but there are several steps that you can take to help ease your symptoms. However, it’s important to remember that SAD affects people differently, so not every strategy will work for everyone.

  1. Get as much natural sunlight as possible: SAD is caused by a lack of sunlight so it’s important to get outside in natural sunlight as much as possible. Additionally, if you work indoors, try to let as much sunlight into your working environment as possible. Open any curtains or blinds and sit by a window if you can.
  2. Exercise regularly: Regular exercise can boost serotonin, endorphins, and other feel-good brain chemicals. In fact, exercise can treat mild to moderate depression as effectively as antidepressant medication.
  3. Connect with others: It isn’t uncommon to want to isolate yourself when feeling depressed, however, self-isolation can worsen feelings of loneliness. Consider making time to spend with loved ones, as finding trusted and supportive people to spend time with can help you feel better and give you a sense of belonging.
  4. Eat a well-balanced diet: Eating a nutritious and varied diet can help maintain energy levels and reduce feelings of lethargy. Furthermore, foods such as whole grains and vegetables are likely to keep you fuller for longer, helping you to avoid the carbohydrate and sugar cravings that can be associated with SAD.
  5. Take steps to deal with stress:

-Figure out the things in your life that stress you out, such as work overload, and make a plan to avoid them or minimise their impact.

Practise daily relaxation techniques such as yoga or meditation.

Do something that you enjoy every day.

(Information source: Help Guide, a non-profit guide to mental health and wellness).


Where to get help for SAD:

If you think you may have SAD, you should talk about it with your GP, as they will be able to look at your own personal situation and suggest treatment options that are right for you. Getting professional help when you need it is really important.

The NHS has explained that the main treatments are:

  • Light therapy – involves sitting in front of a special light box or LED that simulates sunlight, preferably first thing in the morning. It is believed that this may cause the brain to produce more serotonin, while reducing levels of melatonin to help regulate your sleep/wake cycle. For light therapy to be most effective, it is recommended to start it in the autumn, as soon as (or even before) symptoms begin).
  • Psychotherapy (talk therapy) – A form of psychotherapy called cognitive behavioural therapy can help you to:

Learn healthy ways to cope with SAD.

Identify and change negative thoughts and behaviour.

Learn how to manage stress.

Implement healthy behaviours.

  • Antidepressant medicines – Some people with SAD benefit from antidepressant treatment, especially if symptoms are severe.


To conclude, living with SAD isn’t easy, but there are multiple treatment options that your GP can offer you, and several self-help strategies that you could try to incorporate into your daily life to help reduce symptoms and improve your mood.