Seasonal affective disorder

Introduction

Seasonal affective disorder (SAD), or 'winter depression', may affect as many as a third of us, but the problem often goes undiagnosed.

For a smaller number, it can be seriously disabling. This booklet is for anyone who wants to know how seasonal changes in light levels affect behaviour or mood, and what can be done about it.

Why do we have seasonal mood changes?

Most of us feel better when the sun is shining – more cheerful and energetic. On grey, gloomy days, especially in winter, we tend to feel less enthusiastic, more inclined to stay indoors, to do less work, to socialise less and to eat more. The reason for this is the change in the quality and quantity of light.

As winter approaches, there are fewer daylight hours and so, by December, we often get up in the dark and come home from work or college in darkness. What’s more, the shorter winter days don’t have the same light intensity that we get in summer.

For years I suffered from depression. It started in the autumn, as the evenings drew in. By Christmas, I would be so low that I could barely get out of bed… One year, I felt so bad that I went to bed on Christmas Eve and refused to move…

 The cycle of light and dark determines our sleeping and waking patterns. Until the widespread use of electric light, people used to wake and get up with the dawn light and sleep when it became dark. In winter, people would sleep longer and be less active. Nowadays, we tend to override these natural rhythms and manipulate the hours of light and darkness to suit our modern working, social and family lives. Many night-shift workers and jet-lagged air travellers suffer from disrupting their body clocks in this way.

The effects of light

When light hits the back of the eye (the retina), messages are passed to the part of the brain (the hypothalamus) that rules sleep, appetite, sex drive, temperature, mood and activity. If there’s not enough light, these functions are likely to slow down and gradually stop. Some people seem to need a lot more light than others, and these are the people who develop seasonal affective disorder (SAD), to a greater or lesser extent.

Causes and effects

What are the effects of SAD?

Many people report that they eat and sleep more in winter and that long stretches of grey skies make them feel low – this is all perfectly natural. But for those with SAD, the changes in mood and behaviour are much more severe, and happen regularly, each winter, following a seasonal pattern.

Symptoms (for people in Northern Europe) may start emerging between
September and November and continue until March, April or even May. The symptoms go away in spring, either suddenly (with a short period of hyperactivity) or gradually, depending on the amount of sunlight in the spring and early summer.

Symptoms

Once someone has experienced two or three winters of symptoms, they can be said to be suffering from SAD. The symptoms are many and varied, and people can experience any of the following common effects:

• lack of energy for everyday tasks
• being more prone to illness – some people with SAD may have a lowered immune system during the winter, and may be more likely to get colds, infections and other illnesses
• sleep problems
• depression – feeling sad, low, weepy, guilty, a failure; sometimes hopeless and despairing, sometimes apathetic and feeling nothing
• mood changes – in some people, bursts of over-activity and cheerfulness (known as hypomania) in spring and autumn
• anxiety – tenseness and inability to cope with everyday stresses; panic attacks
• social problems – irritability, and not wanting to see people; abusive behaviour
• concentration problems
• overeating – particularly craving carbohydrates and putting on weight (which may increase negative feelings)
• loss of interest in sex or physical contact
• alcohol and drug abuse

A small percentage of people have very severe symptoms and can’t function in winter without continuous treatment. Many can find it difficult to study or hold down a job during this season, because they feel lethargic or sleepy and find it difficult to concentrate. Their relationships can be put under strain, and may even break up, because they become irritable and less able to consider the feelings of others. However, for some people, symptoms are fairly mild and last for a shorter period, mainly during December, January and February, and are known as the ‘winter blues’, or sub-syndromal SAD.

What causes SAD?

The exact causes of SAD are still unclear. Scientists and doctors worldwide have been researching SAD since the early 1980s, and there are several theories as to what causes it and what triggers it.

Low serotonin levels

There are several brain chemicals involved in SAD, but the main one is serotonin. People experiencing depression have been found to have lower levels of serotonin, particularly in winter. It is thought that serotonin might not work properly in people with SAD.

Low melatonin levels

I first started feeling low in the winter months in my late 20s, after years of being a night owl. Now, every autumn when the clocks change, I feel like I’m being buried alive. I want to hide away and hibernate until it’s all over.

When it’s dark, the pineal gland in the brain produces the hormone melatonin which makes us sleep; when it becomes light again, it stops producing melatonin and we wake up. This process also occurs in animals; and those which hibernate have been found to have very high levels of melatonin.

Some people with SAD have likened their symptoms to a desire to hibernate for the winter. And it has been found that people with SAD produce much higher melatonin levels in winter than those who don’t have SAD symptoms, but their summer levels are normal.

When treated with bright light, melatonin levels drop to normal. However,
suppressing melatonin doesn’t cure the symptoms, so this factor isn’t likely to be the sole cause of SAD.

Disrupted body clock

The suprachiasmatic nucleus (SCN), in the brain, sets a person’s body clock (circadian rhythm) by ‘noticing’ when it’s daylight or not. One theory is that if it becomes ‘faulty’ it can slow down the body clock, causing lethargy and depression. However, bright light (in the morning or from light treatment) can ‘reset’ the body clock and alleviate the symptoms, so the faulty SCN can’t be the only factor involved in this ongoing disorder.

Possible triggers

No one really knows what triggers SAD, but it has been linked to events such as childbirth, hysterectomy or other hormonal upheavals. It’s been suggested that postnatal depression may be SAD, brought on by the considerable stress of having a baby. Note: if you already suffer from SAD, and are hoping to start a family, spring is probably the best time to have a baby. SAD has also been reported to have been triggered by a major loss or bereavement, or by serious illness, all of which are common triggers of depression.

Who gets SAD?

SAD can begin at any age, most commonly between 18 and 30, with more people developing it before the age of 21 than after. It’s thought that twice as many women as men have SAD, but it’s difficult to get an accurate picture, as men can find it harder to admit to depressive symptoms.

It’s extremely rare to find people with symptoms of SAD living within 30 degrees of the equator, where daylight hours are long and extremely bright. But it can affect people anywhere else in the northern and southern hemispheres – from Scandinavia, in the North, throughout Europe, in most of North America and North Asia, and as far up as the southern parts of Australia and South America. It is estimated that around 10 per cent of the population of Northern Europe have milder symptoms of SAD, while about two per cent experience severe symptoms. Some people even get SAD in summer, during dull periods.

People who have lived near the tropics for part of their lives and then emigrated to this country seem to be more vulnerable to SAD symptoms. Note: people from different cultural backgrounds may show symptoms differently, and this can sometimes lead to being misdiagnosed with schizophrenia or bipolar disorder, for instance.

Treatment and support

What sort of treatment is there?

Many people make their own diagnosis and treat themselves. However, talking to your GP will give you further information and treatment options. Ideally, any treatment (including light treatment) should be medically supervised, either by a GP or a SAD clinic. Unfortunately, there are only a few NHS clinics in this country, and you may have to wait a long time for an appointment.

Bright light therapy

Bright light is the most effective treatment for most people. Light therapy (phototherapy) helps many people, usually within three to five days. It means spending some time each day exposed to very bright light, at least ten times the intensity of domestic lighting. Ordinary light bulbs and fittings are not strong enough, and ordinary suntan lamps or boxes, which emit high levels of ultra violet (UV) light, should not be used. Light treatment with the correct lights is perfectly safe: enough UV is screened out, so there is no danger of eye problems or skin cancer. Light is measured in ‘lux’. To be effective, a light intended to reduce the symptoms of SAD should be at least 2,500 lux, although most manufacturers now produce 10,000 lux models. There’s a range of light equipment available, including light boxes, visors and dawn simulators.

• The light boxes range in size from a small TV-sized tabletop box to a wall-mounted window-type fixture. They contain a number of bright light tubes covered by a screen. You sit about half a metre to a metre away from it, and can carry on with normal activities, such as reading, working, eating or even watching TV.
• A portable light visor fits on your head, shining light directly into your eyes and giving you complete freedom of movement.
• A dawn simulator is a bedside light, connected to an alarm clock, which mimics a sunrise and wakes you gradually.

You can use your lights at any time of day, except just before going to bed. Morning light seems to work best for people who tend to be more active later in the day and early evening light can help those who prefer mornings. Average use is one or two hours a day and the maximum about four hours. Some light boxes are much brighter and can cut treatment time down to half an hour. Use one daily in winter and during dull periods in the summer, beginning in the autumn, when the first symptoms appear.

The benefits continue as long as it’s used every day. Once your routine is established, you can take occasional days off or go away for a long weekend, as long as you start again as soon as you return. If you have already been experiencing severe symptoms before you start light treatment then you are unlikely to get much benefit from it. Manufacturers advise trying again earlier the next year.

Occasionally, people report headaches, irritability or, in very rare cases, nausea when using light treatment. Changing your position may help, but if problems persist, you must stop using light treatment. Anyone using light treatment, regularly, should tell their optician and have an annual eye check up. Anyone with existing eye problems should ask whether lights are safe. Light boxes are not available on the NHS, so it’s best to try out light treatment before buying. Manufacturers and suppliers may be able to offer you a free trial. (See ‘Useful contacts’)

Talking treatments

Talking treatments, such as counselling, psychotherapy or cognitive behaviour therapy (CBT) can be extremely useful in helping people to cope with SAD symptoms. They also help to uncover other factors that may be contributing to your symptoms, and enable you to do something about them.

It’s possible to get CBT on the NHS in several places, and the NHS provision of CBT is developing fast under the government funded programme ‘Improved Access to Psychological Therapies’ (IAPT) (however, in some areas the service is still patchy). In addition to the services offered via IAPT, some counsellors and psychologists offer CBT under the NHS, for example at GP surgeries. Some nurses, doctors, occupational therapists and clinical psychologists working in community mental health teams can also provide CBT. Some NHS Trusts will have specialist therapy services. Your GP may be in the best position to give you information about local services. Various organisations offer low-fee schemes. (See Useful contacts for more information.)

Antidepressants

SSRI (selective serotonin reuptake inhibitor) antidepressants, such as paroxetine (Seroxat), sertraline (Lustral) and fluoxetine (Prozac),which increase the activity of serotonin, have proved successful in severe cases of SAD. They can be combined with light treatment.

Older antidepressants such as amitriptyline, imipramine and dosulepin are less commonly used nowadays and more problematic, because they increase symptoms like sleepiness. (See Mind’s booklet Antidepressants for information about side effects and withdrawal.)

What else can I do to help myself?

Make the most of natural light

We know that being outdoors throughout the winter isn’t a cure, because many farmers and outdoor workers have SAD. However, it is still worth taking opportunities to be exposed to natural light when possible. Going outdoors, particularly around midday or on bright days, can be effective in reducing symptoms. If it is safe to do so (i.e. when you will not impair your vision), try to wear sunglasses a bit less often: this will allow greater exposure to natural light. Additionally, having pale colours within the home that reflect light from outside can be helpful.

Avoid stress
Your body is less able to deal with a high level of pressure within the winter months. (See How to manage stress.) Even if you can’t curl up in bed and sleep for six months, you can simplify your life in winter. Be ruthless about which tasks can be left until summer, especially major ones, such as changing jobs, moving home, extra housework and decorating or repairs. Plan ahead for the winter. Buy Christmas presents, stock up store cupboards and give parties in the summer, when you want to.

Pamper yourself physically with a massage, or learn how relaxation exercises can help you unwind.

Exercise and eat well
You need to keep active during the winter, but with routine stress-free activities that don’t require too much concentration or drain your energy.
There’s plenty of evidence to show how good physical activity is for mental wellbeing, and for helping with problems such as depression. One research study showed that a daily one-hour walk, in the middle of the day, could be as helpful as light treatment for coping with the winter blues.

A healthy diet is also important, and you should try to balance the common SAD craving for carbohydrates, such as pasta and potatoes, with plenty of fresh fruit and vegetables. Some people find that taking extra vitamin B12 is helpful.

Consider taking St John’s wort
St John’s wort is a popular herbal remedy available over the counter in the UK. There is some evidence that it is an effective treatment for mild to moderate depression. This would be appropriate for the winter blues, although not for severe SAD. Some people have reported positive benefits, but one of the main side effects of St John’s wort is that it increases skin sensitivity to light, and this means that you should not take it if you use a light box. It should not be taken at the same time as other antidepressants. The UK Commission on Human Medicines warns that St John’s wort reduces the effectiveness of several types of prescribed drugs, including the contraceptive pill, so it is important to check with your doctor or a pharmacist if you are taking any other medication and are thinking of taking St John’s wort.

Visit somewhere with more light
If you can afford it, a holiday to a sunnier climate would be likely to reduce symptoms, but you may find that on returning to the UK your SAD will temporarily become much worse. It seems that the contrast in light levels can do more harm than good sometimes, so consult your doctor or the SAD Association if you have any doubts. (See ‘Useful contacts’)

Improve your support network
Think about joining a support group. Sharing your experience with others who know what it’s like is very therapeutic. Knowing that you are not alone and that help is available can make SAD much more bearable. Get as much support as possible from your family and friends. Tell them about the condition, so they know what to expect and how to help. If your own GP doesn’t know about SAD, you can get more information from the organisations listed below.

Friends and family

How can family and friends help?

This section is for friends and family who want to support someone they know who has seasonal affective disorder.

Try to accept that your friend or family member feels awful. Being hostile about it or teasing them is likely to make things worse. Having SAD can be like having any other potentially serious medical condition. It can damage quality of life greatly, and leave someone experiencing it feeling very ill for half of the year.

Offer practical assistance, if you can. It’s important to get treatment and other matters organised during the summer, well before symptoms begin. As soon as you notice signs of lethargy, encourage the person to start their treatment programme and to stick with it. If they are using light treatment, build it into daily life. If the person needs an hour’s light before going to work or college, make sure other chores or responsibilities don’t interfere. Help them to pace themselves, and be sensitive about making too many demands on them (such as inviting a houseful of guests to stay). It’s in nobody’s interest if they become more stressed.

It can be very upsetting for you if the other person is constantly irritable and seems unwilling to give or accept love. Relationships can be strained to breaking point if one partner feels it’s all too one-sided. But experiencing depression, including SAD, can have a devastating effect on someone’s emotions, such as being unable to feel happy, caring and loving in the usual way. However it may seem, they are not deliberately rejecting you. They may be desperate for love and care, and yet not able to accept it, when it’s offered. Be patient, but insist they get treatment, so that you can then both look forward to better times.

Useful contacts

Useful contacts

British Association for Behavioural and Cognitive Psychotherapies (BABCP)
tel. 0161 705 4304
web: babcp.com
Can provide details of accredited therapists.

British Association for Counselling and Psychotherapy (BACP)
tel. 01455 883 300
web: bacp.co.uk
For Information about counselling and therapy. See website or sister website, itsgoodtotalk, for details of local practitioners.

 The Institute for Complementary Medicine (ICNM)
tel. 020 7922 7980
web: icnm.org.uk
Has a register of professional, competent practitioners. 

Lumie
tel. 01954 780 500
web: lumie.com
Information on light therapy equipment and SAD, and online shopping available.

National Light Hire Company
information line: 01704 500 505
web: sad-lighthire.co.uk
Light therapy equipment and information. Specialists in SAD therapy.

NHS Direct
tel. 0845 46 47
web: nhsdirect.nhs.uk
They can advise you on local services for people with personality disorders and courses of action.

SAD Association
PO Box 989, Steyning BN44 3HG
web: sada.org.uk
A charity raising awareness and providing information about SAD.

UK Council for Psychotherapy (UKCP)
tel. 020 7014 9955
web: psychotherapy.org.uk
Has a voluntary register of qualified psychotherapists.

Published 2011
To be revised 2013
See our guidance on reproducing our information