What is seasonal affective disorder (SAD)?

Don’t let the UK weather derail your mood or health goals. Learn about seasonal depression as we transition into autumn and winter.
Published 17 September, 2018

Beat the end-of-year blues

Making a healthy choice is easier when your head’s in a happy space, but remaining upbeat in the face of colder, darker days - not to mention a global pandemic and associated lockdown restrictions - can be a challenge. 

Conkers, crumbles and autumn colours are some of the wonderful upsides of this time of year, with snow and Christmas markets to follow. But watching summer slip away isn't always a cause for celebration.

As we watch the nights draw in and the weather get gloomier, the colder and darker days can do more than give you a case of the ‘winter blues’ – it can cause something called seasonal affective disorder. Find out whether you’re at risk, and what you can do about it.

What is seasonal affective disorder?

Also known as winter depression, seasonal affective disorder (SAD) is a type of depression related to the change in seasons. “People who experience SAD will notice a gradual depression set in late autumn or early winter, which then alleviates in spring,” says Professor Leon Lack, from the school of psychology at Adelaide’s Flinders University in Australia.

RELATED: The truth about depression

Why does it happen in winter?

“Compared to the warmer months, winter days are shorter and tend to contain less sunlight.” says Professor Lack. Not only can this reduce levels of serotonin, a brain chemical that affects mood, it can also ‘delay’ your body clock, so that your sleep cycle falls out of sync with your daily commitments. “The effect is that falling asleep takes longer and then when your morning alarm goes off at the usual time you feel like you’re being woken up at 3am. When that continues day after day, it contributes to feelings of depression.”

Is it SAD or the 'winter blues'?

Feeling like the weather’s getting you down doesn't necessarily mean you have SAD. Some studies show that around 10 per cent of the population in northern hemisphere countries are affected by SAD to some degree.

SAD symptoms include difficulty falling asleep and waking up; feeling sluggish and unmotivated, particularly in the morning; increased appetite; weight gain; and a persistent low, sad or depressed mood. If you notice those symptoms and they worry you, see your GP – a number of treatments are available for SAD.

Who is particularly at risk? As well as being more common in women than men, a family history of SAD and having experienced depression in the past can increase your risk of the disorder.

How can I avoid SAD?

A good place to start is doing what you can to keep your body clock on track as the days grow shorter and darker. As well as helping to prevent SAD, it might help you shake the more common winter blues, too. To do it:

1. Don’t oversleep at the weekend
Grabbing the opportunity to catch up on sleep on a Sunday morning might seem like a good idea, but a long lie-in will will delay your body clock even further, so instead of feeling refreshed on Monday, you’ll feel more tired. That's not to say you shouldn't treat yourself to an extra half hour or so: read how a short lie-in could benefit your health.

2. Turn the lights down at night
Exposure to artificial light at night inhibits the production of the melatonin that’s required to make you sleepy. “And avoid looking at your computer, phone or other screens, in the hour before bedtime,” says Professor Lack. “As well as the light they emit, the content can stimulate your brain, which delays sleep.”

3. Get some light first thing in the morning
It suppresses your body’s production of melatonin, the hormone that encourages sleep, and makes falling asleep at night easier, too. “Outdoor light is most effective, but if it’s dark outside when you wake up, switch on the lights inside as soon as you get up,” says Professor Lack.

4. Do something active every day
As well as encouraging a better night’s sleep, a 2017 study found that regular physical activity also regulates the expression of a key ‘body clock gene’. Make the most of it by heading outdoors to move – the sun’s ultraviolet radiation is the best natural source of vitamin D, low levels of which have been linked to the onset of S.A.D. Remember to use sun protection when the UV Index is 3 or above.

5. Go to bed on time
While research shows that your ‘wake time’ has more power over your body clock than your ‘bedtime’, whenever you change the timing of your sleep, it can affect your clock’s natural rhythm. Make a conscious effort to avoid those late nights.

5 ‘get happy’ tips to try

When you need a quick fix to give your mood a boost this season, try:

1. Making someone else smile
When you set that as your goal for the day, and do what’s required to make it happen, you’ll feel genuinely happier once you’ve reached it.

2. Pushing your shoulders back
Shifting your body posture into a more upright, open position improves your mood. Why? Scientists say that ‘positive’ body postures open the same biological pathways that exercise works on to increase happiness.

3. Listening to some upbeat music
Focus on the fact that you’ve chosen that particular track because you’re trying to boost your mood, and it works as an instant ‘get happier’ fix.

4. Giving back a little
Making a small donation to a cause that means something to you or helps you feel more socially connected will make you feel happier.

5. Buying yourself some flowers
People who did that, and positioned them where they’d see them often, as part of a Harvard Medical School study, felt happier and less negative as a result.