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Seasonal Affective Disorder (SAD)

If you dread the winter because it makes you feel constantly tired, moody, irritable and low, you may be one of the many people in the UK who experiences Seasonal Affective Disorder (SAD).

There are no official figures to suggest how many people have SAD in the UK. The Royal College of Psychiatrists claims three in 100 in this country are affected (i), while Patient suggests the figure is more like between three and six in 100, with as many as 12 - 13 per 100 affected by a less severe form of SAD called winter blues or sub-syndromal SAD (S-SAD) (ii). A study published in the British Medical Journal, meanwhile, claims up to six percent of UK adults have ‘recurrent major depressive episodes with seasonal pattern’ (iii).

It is, however, thought to be three times more common in women than in men, and usually affects women of childbearing age (it’s less common in children and older adults)(i).

Formerly recognised as a disorder in the 1980s, SAD is a real illness, and can affect you and your ability to function normally as much as any other type of clinical depression. Experts still don’t know what causes it. But many believe it’s caused by lack of natural daylight, since symptoms usually start around the time when the clocks go back in the autumn and lasts until spring.

Hormone connection

Some also believe the hormones melatonin and serotonin are involved, though it’s not fully understood how (iv). For instance, low light levels are thought to increase the brain’s production of melatonin, which can disrupt the body’s internal clock (or circadian rhythm). The pineal gland produces more melatonin during the hours of darkness, making you feel sleepy. But some people who have SAD are thought to produce more melatonin than usual, making them feel tired throughout the day.

Fewer hours of sunlight during the winter months is also thought to lead to lower levels of serotonin – often called the ‘feel-good’ chemical – which can affect your mood.

What we do know is SAD can cause several symptoms that can be severe enough to have a significant impact on your daily life. These symptoms include those associated with depression such as low mood, irritability, low self-esteem, stress, anxiety, a lack of interest in life in general, and feelings of despair, guilt and worthlessness. There are other symptoms too, including low energy, sleepiness, insomnia, concentration difficulties, low libido and carbohydrate cravings. You may also find your resistance to winter colds and other infections is lower than at other times of the year.

Winter blues

Many people find they feel a little low during the winter months, but they don’t develop all of the symptoms of SAD. If you have winter blues, you may feel lethargic and not want to get out of bed in the mornings. There’s a good chance you’ll have cravings for stodgy and sugary foods too, which may lead to weight gain. But your low mood and anxiety levels will usually be much milder than someone with SAD.

Meanwhile, SAD may be triggered by other factors such as illness, childbirth or a change of environment. It’s also possible that there may be a genetic element involved with some people, since the disorder can run in families (around one in seven close relatives of people with SAD are also affected)(v).

Far more rare is summer SAD, where people report feeling down in the summer months instead of the winter (this may be caused by a reaction to heat rather than increased light levels).

See your GP if you’re experiencing SAD symptoms and are finding it hard to cope. There are several treatments your doctor may offer, including medication such as antidepressants or psychology-based treatments such as cognitive behavioural therapy (CBT).

If your symptoms are mild, however, there are several things you can do to help yourself.

How light therapy works

One of the most common self-help treatments for SAD involves increasing your exposure to light, often by using an artificial light source (SAD therapy lights are often called light boxes). The principle behind light therapy is to compensate for the lack of bright daylight hours during the winter.

A SAD light box produces very bright non-UV light at up to 10,000 lux (this compares to ordinary domestic or office lighting, which produces 200-500 lux). Treatment is simple: all you have to do is sit in front of your light box for up to half an hour a day.

Many experts believe light therapy works by suppressing your melatonin levels, which means you may feel more alert and awake (vi). It’s also thought to help boost your brain’s production of serotonin, which may keep your mood more stable.

Light receptor sensitivity

There’s also some evidence to suggest that the light receptors in the retinas in the eyes – the rods and cones – respond differently in people with SAD compared with those who don’t have seasonal depression. During the summer, these light receptors react similarly in people with and without SAD. But in winter, the light receptors in people with SAD may be much more sensitive. One study suggests light therapy may help the retinal response in people with SAD get back to normal within just four weeks (vii).

More generally, light therapy is believed to be more effective when used during the morning around breakfast time (if you use your light box during the evening, it may keep you awake at bedtime). Light therapy may not work for everyone, but if it’s going to help you, you should usually notice an improvement quickly, even during the first week.

Help with waking up

Other light therapy devices include dawn-simulating alarm clocks. These are thought to be helpful if you find it difficult to wake up on winter mornings, as they switch on about an hour before you need to wake up and gradually get brighter.

Light boxes and dawn simulators aren’t available on the NHS. But if you decide to buy your own, make sure it has been made by a fully certified manufacturer and is designed for treating SAD.

On the other hand, if your symptoms are mild, getting outdoors during the winter as often as possible whenever the sun is bright may be all you need to do. Try getting out of your home or office at some point in the middle of the day. And if you can’t get outside, try sitting near a window whenever possible to soak up some natural light.

Many nutritionists and mental health experts believe that what you eat can make an enormous difference to your mood, particularly if your mood suffers during the winter. Foods that contain the amino acid tryptophan may be particularly useful during the winter, as tryptophan converts into serotonin in the brain.

Foods rich in tryptophan include:

  • Bananas

  • Turkey

  • Chicken

  • Fish

  • Cheese

  • Eggs

  • Nuts

  • Milk

  • Avocados

  • Pulses

Some experts also recommend eating carbohydrate snacks throughout the day, since carbohydrates are thought to help tryptophan cross the blood-brain barrier as well as help with the conversion to serotonin in the brain.

However, try to choose small, regular doses of complex carbohydrates such as brown rice, whole meal bread and whole meal pasta. These release glucose into your bloodstream more slowly than processed carbohydrates such as white bread and sugary foods, which may help keep your blood sugar level stable.

This is important as wildly fluctuating blood sugar levels can make you crave sweet, stodgy foods as well as make you feel tired and irritable. Other ways to keep your blood sugar stable include avoiding sugary foods, not going for too long without eating anything (don’t let yourself get too hungry) and having smaller main meals to allow for more healthy snacks in between.

Foods containing omega-3 fatty acids may also help with serotonin production, so aim to eat eat oily fish such as salmon, mackerel, sardines and fresh tuna at least once a week (if you’re a vegetarian or vegan, try adding flaxseeds or chia seeds for an omega-3 boost).

You could also try eating more foods that contain the amino acid phenylalanine, which is converted in the body to another hormone called dopamine. Low dopamine levels may be linked with low mood and low energy levels too, so try boosting yours by eating foods such as soya, cheese, seeds, nuts, chicken, turkey, whole grains, eggs, fish, seafood, beans and lentils.

Move more to feel better

Meanwhile, being physically active is widely accepted as an effective way to boost your mood and relieve depression (viii). Experts believe it’s because exercise stimulates your brain to produce feel-good hormones, including serotonin. And while you may not feel like going outside much during the winter months, exercising outdoors – particularly when it’s a bright sunny day – may be even more beneficial for relieving SAD or winter blues symptoms.

Try taking a walk in the park instead of having sandwiches at your desk at lunchtime, or walk to the shops instead of taking the bus. But if you can’t get out because the weather’s too bad, staying active indoors will help too. You could go for a swim, join an aerobics, yoga or Pilates class, or work out at home to a fitness DVD.

More self-help tips for SAD sufferers

Staying active and eating a healthy diet are achievable ways to relieve the symptoms of SAD and the winter blues. But there are other things you can do to help yourself too, including the following:

Take a break

Even if you don’t feel like exercising, having a break outdoors can treat your brain to a dose of natural daylight. Aim for a good hour’s break in natural light – but if you don’t have an hour, try to stay outside for 20 minutes.

Follow the sun

If you can manage a longer break, try going away somewhere warm and sunny during the winter instead of taking your holiday in the summer. For many people with SAD, the symptoms are worse during January and February, so why not take advantage of the off-peak package holiday deals on offer at that time of year? The extra sunlight could help make you feel better for weeks – or even longer – after you return home.

Soak it up next summer

Not everyone can get away during the winter, so if you’re a summer holiday person, try to make the most of the sun next year and you could find your serotonin levels will stay higher for longer into the winter season. Do, however, be careful not to over-expose your skin to strong sunlight (see our guide to sun protection for more information).

Keep warm

One of the things most people dislike about winter is the cold. And while there’s no clear evidence yet that cold temperatures contribute towards the development of SAD, some people with the disorder say their symptoms improve when they keep warm. So when it’s cold outside, wrap up well before going outdoors, and make sure your home and workplace are properly heated. Try using a hot water bottle to keep you warm at night, or invest in an electric blanket (never use a hot water bottle at the same time as an electric blanket).

Manage stress levels

If you feel more stressed than usual during the winter, it’s no surprise. The run-up to Christmas can be a particularly stressful time for many people, for example. So try to plan any stressful events or activities that can be put off for the spring and summer instead (in fact, it can be useful to make plans for the spring, as it will remind you that winter won’t last forever). Also don’t forget to make time to unwind on a regular basis – indulge yourself in a little of whatever helps make you feel calm.

Natural support for SAD symptoms

If you’re affected by SAD symptoms, there are several natural remedies that may help. Some may help maintain your mood, help reduce anxiety and generally support your cognitive functioning. They include the following:


The non-essential amino acid 5-HTP – or 5-hydroxytryptophan – is a natural substance that converts to serotonin once in the brain. And since many conventional antidepressant medicines work by boosting brain serotonin levels, 5-HTP has often been studied as a natural alternative for depression and low mood. A few studies even suggest it may be as effective as effective for depression and low mood as certain conventional antidepressants (ix).

St John’s wort

This herbal remedy has been used for many years as a natural treatment for low mood, and has been granted an official traditional herbal registration (THR) for the relief of symptoms of slightly low mood and mild anxiety. It may, however, interact with other conventional medicines. If you take the oral contraceptive pill, tricyclic antidepressants, statins, warfarin or indeed any other type of prescription medicines, speak to your GP before taking St John’s wort.

Fish oils

The omega-3 fatty acids EPA and DHA found in oily fish such as salmon, herring and mackerel may offer cognitive support, including relief from the symptoms of depression. One study suggests that older women suffering from depression may enjoy significant symptom relief after taking high doses of both fatty acids (iv). Other studies have investigated the benefits of EPA and DHA in treating depression, with many suggesting they may be helpful (xi).

If you’re a vegetarian or vegan you can still benefit from an omega-3 supplement, thanks to the availability of products that contain the natural triglyceride (TG) form of omega-3, which is sourced from plant organisms called microalgae rather than fish.

Vitamin D

Since levels of vitamin D drop during the winter – thanks to the fact there’s fewer hours of sunlight during the winter months – many natural health practitioners suggest that vitamin D supplements may be useful for people with SAD. Indeed, one small clinical study has found that taking vitamin D supplements during winter may improve mood (xii). Another suggests that vitamin D supplementation may be helpful for people with clinically significant depression (xiii).

The recommended form of vitamin D is vitamin D3 or cholecalciferol, as it’s the natural form of vitamin D that the body makes when it’s exposed to sunlight. Vitamin D3 supplements are available in tablet form, and now you can get them in veggie-friendly drops too.

However, most vitamin D3 supplements are made from the fat of lamb’s wool, which means they’re unsuitable for vegans. The good news is that vegan vitamin D3 supplements sourced from lichen are now more widely available.

B complex

B vitamins are needed for the production of neurotransmitters in the brain, including those that affect mood, including serotonin and dopamine. In fact one study, which claims vitamin B deficiencies are associated with depression, found older adults who ate plenty of food rich in vitamin B6 and B12 were against depressive symptoms (xiv).

There are many food sources of the various B vitamins (thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), folic acid and B12). But if your diet isn’t as healthy as it should be for any reason, a good-quality B complex supplement may give extra support.

Tackling Seasonal Affective Disorder can be hard, but the seasons will soon change! For even more information on a range of other health conditions, feel free to visit our health library.



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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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