What is seasonal affective disorder (SAD)?
Seasonal affective disorder (SAD) is a type of depression that you experience during particular seasons or times of year. Depression is a low mood that lasts for a long time, and affects your everyday life. This article takes a closer look at what SAD is and what some of the causes.
If you have SAD, you’ll experience depression during some seasons in particular, or because of certain types of weather.
“It’s like having your own portable black cloud.”
It’s common to be affected by changing seasons and weather, or to have times of year when you feel more or less comfortable. For example, you might find that your mood or energy levels drop when it gets colder or warmer, or notice changes in your sleeping or eating patterns.
But if your feelings are interfering with your day to day life, it could be a sign that you have depression – and if they keep coming back at the same time of year, doctors might call this seasonal affective disorder or ‘seasonal depression’.
“In the weeks before the clocks go back I start to feel sluggish and down, it’s harder to keep to my morning routine of going out for a walk before breakfast because it’s wet, cold and dark.”
What are the symptoms of SAD?
If you have SAD, you might experience some of the signs and symptoms below. But it’s different for different people, and can vary season to season, so you might also have other kinds of feelings which aren’t listed here:
- Lack of energy
- Finding it hard to concentrate
- Not wanting to see people
- Sleep problems, such as sleeping more or less than usual, difficulty waking up, or difficulty falling or staying asleep
- Feeling sad, low, tearful, guilty or hopeless
- Changes in your appetite, for example feeling more hungry or wanting more snacks
- Being more prone to physical health problems, such as colds, infections or other illnesses
- Losing interest in sex or physical contact
- Suicidal feelings
- Other symptoms of depression
If you also have other mental health problems, you might find that things get worse at times when you’re affected by SAD.
Sarah's Story
In this audio podcast, Sarah explains how she developed seasonal affective disorder (SAD) and what it's like living with it day to day,
What causes SAD?
The exact causes of SAD aren’t clear. It seems that the things we know can cause depression in general can lead to SAD, and research has also suggested that there are a few things that could contribute to the development of SAD in particular.
Depression can vary a lot between different people and you might have SAD due to a combination of factors, or there might not seem to be any specific reason.
On this page you can find information about possible causes of SAD:
Disrupted body clock
Your brain sets your body clock by the hours of daylight. One theory is that if you experience SAD, this part of your brain isn’t working in the same way. This could mean your body clock slows down, leading to tiredness and depression.
Some researchers think this is because your sleep pattern (also known as your ‘sleep phase’) starts at a different time. This is sometimes described as having a delayed sleep phase.
Daylight and SAD
SAD is thought to be more common in countries where there are greater changes in the weather and daylight hours during different seasons, including England and Wales. People who live near the equator for part of their lives and then move further away may also be especially vulnerable to getting SAD.
High melatonin levels
When it’s dark, your brain produces a hormone called melatonin which helps your body get ready for sleep. Some people with SAD seem to produce much higher levels of melatonin during winter (which is also what happens to animals when they hibernate).
The exact relationship between melatonin and SAD isn’t clear. Researchers have found that if you have high levels of melatonin and you’re exposed to bright light, your melatonin levels drop to a more usual amount. But this doesn’t seem to help with symptoms of depression.
Weather and Temperatures
We all have different experiences of particular seasons and types of weather. You might feel particularly uncomfortable in hotter or colder temperatures, which could contribute to you developing depression (or any existing depression worsening) at those times.
While more people are aware of SAD happening in winter, some people have more difficulty in warmer weather. Some studies have suggested a possible link between higher temperatures and poor mental health, but more research is needed to understand why.
Stressful times of year
Whether or not you have symptoms of SAD, there might be some occasions or times of year you find especially difficult – for example, due to upsetting memories of abuse, bereavement, money problems, housing problems, loneliness or other mental health problems that get worse at particular times of year. Occasions like Christmas can also be particularly stressful, whether or not you have SAD in winter.
For more information on Coping with SAD flow this link for more resources
