Seasonal Affective Disorder (SAD) is a type of mood disorder that occurs at a regular time of the year.  The most common type is depression that affects people during the winter, although it can include mood changes at other times of the year e.g. going high in the summer.

It can happen in up to 1 in 13 people (8%), depending on where you live. In north-west Wales about 1 in 30 people have SAD.  

^{Updated 4.13}

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SAD is a regular change in mood that occurs at a specific time of the year. This is usually thought of as being a depression that occurs in autumn or winter (which is the most common type), but it can include being depressed or going high (mania or hypomania) in other seasons of the year. It needs to have occurred for at least two or three years, plus being fully well at other times of the year.

The other main symptoms (apart from mania or depression) include:

• excess sleepiness
• hugely increased appetite, especially craving for carbohydrates (e.g. bread, pasta etc)
• increased weight
• poor concentration
• loss of interest and lack of enjoyment
• anxiety
• not having much energy
• low libido (sex-drive)
• social isolation (wanting to be alone).

Although many people suffer from SAD about half are given the wrong diagnosis.

^{Updated 4.13}

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Because everyone is unique, everyone's symptoms are different. So, it's not always clear what the right diagnosis is. Here is a list of some other possible causes for the symptoms of seasonal affective disorder. This is not meant to be a textbook list, just some ideas. Some of these can be very rare indeed. Sometimes it doesn't matter anyway as the symptoms need to be treated anyway, no matter what causes them. However, because the symptoms of SAD can be quite vague, diagnosis can be tricky.

• Depression (non-seasonal)
• GAD or Generalised Anxiety Disorder
• Hypothyroidism
• Phase delayed sleep disorder
• Anniversary grief reactions
• Seasonal occupational stress
• Bipolar mania or hypomania
• bipolar mood disorder
• ADHD (Attention Deficit Hyperactivity Disorder) - seasonal highs
• Dementia and Alzheimer's disease
• Chronic fatigue syndrome
• Eating disorders with seasonal variations

Just to confuse matters further, sometimes people have more than one illness (sometimes called "co-morbidity"). For example, if 1 in 10 people get depressed and 1 in 10 people get anxiety, then just by chance 1 in 10 of the depressed people get anxiety as well. However, if you're depressed, you're more likely to be anxious. Co-morbidity means what else the person is more likely to have at the same time. This can make diagnosis more difficult.

• Depression
• ADHD (Attention Deficit Hyperactivity Disorder)
• Dementia or Alzheimer's disease in the early stages
• OCD (Obsessive Compulsive Disorder)
• Pre-menstrual dysphoric disorder (PMT)
• Panic disorder
• Social anxiety
• Eating disorders

^{Updated 5.12}

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Basically, anyone can get Seasonal Affective Disorder. However, there are some "risk factors" that make it more likely that someone will get the symptoms of Seasonal Affective Disorder. This is not a complete list but some of the main ones include: 

• Lack of sunlight
• Being deficient (not having enough) Vitamin D. This is sometimes called the "Sunshine Vitamin" as it is made for the body by the skin when in direct sunlight. Lack of vitamin D can cause rickets (weak bones), thin bones, fatigue and obesity. And possibly seasonal affective disorder, especially in winter. Your levels can be checked by your doctor, and it is possible to have Vitamin D capsules.  
• The time of the year e.g. autumn and winter for depression; spring or summer for hypomania
• Living in high-latitude northern (e.g. northern Europe) or southern hemisphere or being further away from the equator
• Being older - it happens more once people get into their late 20s or older
• Genetics - some people think it runs in families but this is unproven
• Being female - it is slightly more likely in younger women than younger men

Lack of sunlight causes a lack of "Circadian cues" e.g. sunshire, brightness, darkness, changes in noise. This then causes a lack of impulses to the hypothalamus in the brain, the part that controls mood, appetite, sleep, sex drive etc. This causes an increase in melatonin and decrease in serotonin, which causes poor sleep and depression. Many of the medicines that help treat seasonal affective disorder boost serotonin.

^{Updated 5.12}

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To do nothing is a personal choice, unless you are a danger to yourself or others when your symptoms are at their worst. However you need to know the risks and benefits of having no treatment.

The up-side of no treatment is no side-effects from medicines and perhaps getting better by yourself. In any case you know you may begin to feel better when the days start to get longer.

The down-side is having symptoms for longer and not being able to fully enjoy those times of the year when your symptoms are worst, the autumn and winter.

^{Updated 5.12}

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These are some of the risks of having the symptoms of Seasonal Affective Disorder: 

• Seasonal affective disorder can harm your quality of life (Michalak 2007)
• People with seasonal affective disorder get many symptoms, which can stop them being able to be sociable (Westrin and Lam, 2007)
• Feeling tired and sleepy during the day (Rastad 2011). This improves with treatment.
• Slightly higher risk of suicide
• Weight gain

^{Updated 8.12}

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"Prognosis" is the word used for the likely outcome of any condition. There are several things that will help or not help your prognosis or symptoms and the chances of them improving. You should try to make the most or build on the good prognosis factors, and try to work on or minimise the poor prognosis factors. That will give you the best chance of doing well

Factors which may lead to a good outcome (prognosis)

• Taking exercise, especially in daylight
• Sticking to whichever treatment or treatments you choose. Around 1 in 5 people (20%) can expect to get better with treatment (Thaler 2011). Light therapy and antidepressants are equally effective (Michalak 2007)
• Get as much light as possible, especially bright light
• Spending as much time outside as you can
• Learning to manage stress
• If at all possible, have a holiday in winter to somewhere sunny. People with SAD notice that their symptoms get better the nearer they travel to the equator (Lam 1998). This is because the sun is higher in the sky the nearer you get to the equator.

Factors which may lead to a poor outcome (prognosis)

• Not taking exercise in daylight
• Not sticking to your chosen treatment
• Not getting enough light
• Staying indoors

^{Updated 6.12}

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The list here includes most of the main options but does not say what works and doesn't. Many may be used in combination. Most herbal and alternative therapies have not really been tested in the same rigorous way that medicines have.

Our aim is to try to help people who are taking medication (or should be) get the right medicine, dose and take it regularly for as long as is right. Any medicines should usually be part of the overall treatment, although some people are quite happy just to stick with drugs or talking treatments. If your medicines are right, then everything else can fall into place. If the medicines are wrong, then they may make the symptoms worse and self-help will not be as useful.  

Self-help

• Light therapy (needing a special light box) is usually first choice for Seasonal Affective Disorder (SAD) and helps around 8 in 10 people, although it can have a few side-effects. Getting as much natural daylight as possible, especially at midday, will also help. Any light box must have as close to 10000 lux (don't buy a dimmer one, although it has to be said that 10000 lux is very bright) and used for at least 30 minutes at a time. This can cause anxiety, headaches and poor sleep. The effect usually starts in a few days to 3 weeks.
• Taking any medicines regularly and reliably
• Eating healthily and taking exercise  (“exercise to energise”) or being active

Help from others

• Psychotherapy, counselling or any complementary therapy may be helpful because it may help the sufferer to relax and cope with their SAD. There is very little research on talking therapies for SAD.  
• Alternative therapies such as aromatherapy, hypnosis or hypnotherapy, homeopathy (click for a review of the 25 studies in mental health by Davidson 2011) (treating like with like), dietary supplements and negative ion therapy can be used with conventional treatments. Acupuncture is used extensively in many countries and may help anxiety, stress and insomnia. The evidence for these treatments is not very good, especially for SAD. All of these can be used in conjunction with other therapies. If they work then that is fine and we wouldn’t knock them. Click here for a balanced review of complementary and alternative therapies from the Royal College of Psychiatrists (e.g. Ginkgo, Sage, vitamins, other herbals etc, and some useful links).  

Medicines

• Serotonin or noradrenaline boosting medicines can also be effective for depressed SAD, often in combination with light therapy.

^{Reviewed 4.13}

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If you are prescribed a medicine, then there may be many reasons why that one has been chosen. These might include:

• side effects (which ones are important to you)
• local policies or agreements (such as what your GP surgery uses or agreements in your area)
• national policies (e.g. NICE, SIGN - see last question)
• familiarity (it may be better for prescribers to use medicines they are familiar with)
• relative costs for similar medicines (if two medicines are very similar, why waste money on the more expensive one?)
• personal preference (either yours or your prescriber)
• how bad your symptoms are
• any medicine you might have done well with in the past (as it's more likely to work again)

The main medicine treatment options are listed below. They are divided into "Main medicines" and "Others".

For convenience, the "Main medicines” are those medicines that are officially "approved" to treat the condition or symptoms (www.bnf.org/bnf/) and which are listed in the British National Formulary (BNF). To be listed in the BNF there needs to be good evidence that the medicine works and that the manufacturers have applied for a license (a long and costly exercise). "Others" are those medicines where there is some evidence that they help, but either not enough for a license or that no license has been applied for. These should usually only be used where other standard treatments have failed.

Main medicines

• There aren’t any medicines licensed for SAD in the UK.

Others:

• Antidepressants such as bupropion (this is usually used in UK to help people to stop smoking, but is a recognised treatment for SAD in USA), SSRIs (such as citalopram, escitalopram, sertraline, fluoxetine), reboxetine, moclobemide and venlafaxine

• Agomelatine might be an option, and is being researched at the moment

  ^{Reviewed 4.13}

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Download a handy summary chart (PDF format) comparing the main medicines for Seasonal Affective Disorder e.g. names, how they work, doses, how long they take to work, some side effects, how long to take and how to stop.

^{Updated 5.12}

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You should think carefully about taking any chemical that affects your body, including your brain. So think carefully before your next cup of tea or coffee! It is possible that talking therapies and antidepressants together might be a good option.

For an appeal for everyone to have a sense of balance about medicines and talking therapies please click here for our take on it.

^{Reviewed 4.13}

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This is not clear. Nearly all the studies have only lasted for 8 weeks or so. You may decide just to take an antidepressant just for your season of high-risk of depressed mood.

^{Reviewed 4.13}

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Before going onto another medicine, it is worth trying to get the best out of the first one. There is a risk that switching medicines too quickly means you don’t get the best out of one medicine. Then perhaps you start to search for the “magic bullet”, expecting the drugs to work quicker and having less patience. There are of course no “magic bullets”. Most symptoms have started to happen over a few weeks, months or years, not a few days, so it is perhaps unfair to expect them to go over a few days. The symptoms are more likely to go gradually over weeks or months. If side effects are the main problem with a medicine, try to cope with these by e.g. changing times, splitting the dose, manage side effects etc.

The best thing to do is set out your aims of success of any treatment in advance and be realistic. If you decide to stop, then that’s your decision, but make sure you consider the chances of becoming unwell again (and consequences of that to yourself and the people close to you).

• For medicines such as the SSRIs (mostly used for depression) and bupropion (mostly used for smoking cessation), it isn’t entirely clear but most of the trials have shown an effect over 8 weeks so you should probably give them 6-8 weeks before making a decision.
• Some trials of bupropion and sertraline (an SSRI) for winter depression have started the medicine in autumn while the person is still well, thus stopping the person becoming depressed, then stopping again in spring

  ^{Reviewed 4.13}

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There are no easy answers to this and it is a very individual choice. Generally one medicine should always be the aim but combinations (often called “polypharmacy”) sometimes help. It is rarely of any use to combine drugs with similar ways of working. Below are some of the combinations that are used with the reasons. This is not a complete list but you might want to talk to your prescriber about any combinations not on this list you may be prescribed.

It would usually only be necessary to take one medicine at a time for winter depression. Bupropion has a slightly different way of working than the SSRIs so there might be some logic in combining them.

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If you want to read up a bit more on the best treatments, there are many guidelines that you can look at. Probably the most important of these for England and Wales are those produced by NICE (the National Institute for Health and Clinical Excellence). NICE is an independent body that is asked to produce advice about preventing and treating illnesses and promoting good health. Scotland and Northern Ireland have their own similar bodies.

Each set of NICE Guidelines is written by an independent and carefully chosen group of specialists and experts (including service users and carers). They carefully review the available evidence and base their guidelines on this.

There are two main types of NICE guidance:

• "Technology appraisal". These look at an "intervention" (i.e. a medicine, a surgical operation etc) and decide if they think the evidence is good enough to make this intervention a standard and/or if it is cost-effective compared to other treatments
• "Clinical guidelines", which look at a particular condition (e.g. hypertension, lung cancer, depression, Parkinson's disease, bipolar disorder etc) and give guidelines covering medicines, services, support etc.

The guidelines are well intentioned and give generally sound guidance (although these are sometimes controversial). They are, however, only "guidelines", so are not rigid instructions.

When NICE issues a guideline, it produces a full set, and all of these are available on the NICE website:

• Full guideline (very long and detailed, often several hundred pages, for anorak healthcare professionals only)
• Official guideline (usually 10-30 pages, the summary version for healthcare professionals)
• Quick reference guideline for healthcare professionals (usually only a couple of pages)
• User-friendly summary for service users, carers and the general public

These should then be reviewed, usually about 4-5 years or sooner if more information becomes available.

As a general rule, you should start with treatments recommended by NICE as these are the ones with most evidence that they work. However, if these do not help you, it may be useful to try other treatments.

• NICE (no guidance on seasonal affective disorder yet)
• Scottish Intercollegiate Guidelines Network (SIGN)
• Northern Ireland

There are plenty of other guidelines and so-called "consensus statements" (where a group of experts and specialists pool their ideas, based on their own experiences as well as what the published papers say, rather than just what the published studies say). These will have been produced for healthcare professionals by such bodies as BAP (British Association for Psychopharmacology).

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Use the resources below to find out more information about Seasonal Affective Disorder (SAD). Please note that this is not an exhaustive list. We welcome your feedback on resources that you think should be listed here.

Mental Health Ireland has a great links page on this extensive site

Your Mental Health Ireland, with a young person’s page as well

The British Association for Psychopharmacology has a BAP public area, which has loads of interesting articles, some mentioning seasonal affective disorder.

The Big White Wall is a 16+ safe, anonymous web-based service for people experiencing emotional or psychological distress provided entirely online. Professionally staffed 24/7 it offers a wide range of services for improving mental wellbeing including tests, peer support, individual and group therapies, articles, tips and creative self expression. Simply click on the link to learn more, or to join for £2.00 a week.

^{Updated 12.12}

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