What is seasonal affective disorder

Seasonal affective disorder (SAD) is a type of depression that comes and goes in a seasonal pattern.

Seasonal affective disorder is sometimes known as “winter depression” because the symptoms are more apparent and tend to be more severe during the winter and autumn and not during the spring or summer. This is often referred to as suffering the winter blues. A small proportion, however, are depressed only during the late spring and summer.

The symptoms often begin in the autumn as the days start getting shorter. Seasonal affective disorder typically most severe during December, January and February.

Seasonal affective disorder often improves and disappears in the spring and summer, although it may return each autumn and winter in a repetitive pattern.

Symptoms of seasonal affective disorder can include:

• a persistent low mood
• a loss of pleasure or interest in normal everyday activities
• irritability
• feelings of despair, guilt and worthlessness
• feeling lethargic (lacking in energy) and sleepy during the day
• sleeping for longer than normal and finding it hard to get up in the morning
• craving carbohydrates and gaining weight
• thoughts of death or suicide

For some people, these symptoms can be severe and have a significant impact on their day-to-day activities.

In North America, seasonal affective disorder may affect as many as 6 of every 100 people. About 70-80% of those with seasonal affective disorder are women, although it can affect either sex and any age. You are also more likely to have SAD if you or your family members have depression. The most common age of onset is in one’s 30s, but cases of childhood seasonal affective disorder have been reported and successfully treated. For every individual with full blown seasonal affective disorder, there are many more with milder “Winter Blues.” It occurs throughout the northern and southern hemispheres but is extremely rare in those living within 30 degrees of the Equator, where daylight hours are long, constant and extremely bright.

No laboratory tests are available to detect SAD. Your health care provider will make the diagnosis from your symptoms, medical interview, and examination.

Seasonal affective disorder light therapy or bright light therapy has been shown to suppress the brain’s secretion of melatonin. Although, there have been no research findings to definitely link this therapy with an antidepressant effect, many people respond to this treatment. The device most often used today is a bank of white fluorescent lights on a metal reflector and shield with a plastic screen. For mild symptoms, spending time outdoors during the day or arranging homes and workplaces to receive more sunlight may be helpful. One study found that an hour’s walk in winter sunlight was as effective as two and a half hours under bright artificial light.

If seasonal affective disorder light therapy doesn’t work, an antidepressant drug may prove effective in reducing or eliminating SAD symptoms, but there may be unwanted side effects to consider. Discuss your symptoms thoroughly with your doctor and/or mental health professional.

Seasonal affective disorder outlook (prognosis)

The outcome is good with continuous treatment, though some people may have the disorder throughout their lives.

Seasonal affective disorder complications

Take signs and symptoms of seasonal affective disorder seriously. As with other types of depression, seasonal affective disorder can get worse and lead to problems if it’s not treated. These can include:

• Social withdrawal
• School or work problems
• Substance abuse
• Other mental health disorders such as anxiety or eating disorders
• Suicidal thoughts or behavior

Treatment can help prevent complications, especially if seasonal affective disorder is diagnosed and treated before symptoms get bad.

Seasonal affective disorder (SAD) causes

The exact cause of seasonal affective disorder (SAD) isn’t fully understood, but it’s often linked to reduced exposure to sunlight during the shorter autumn and winter days.

The main theory is that a lack of sunlight might stop a part of the brain called the hypothalamus working properly, which may affect the:

• production of melatonin – melatonin is a hormone that makes you feel sleepy; in people with seasonal affective disorder, the body may produce it in higher than normal levels
• production of serotonin – serotonin is a hormone that affects your mood, appetite and sleep; a lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression
• body’s internal clock (circadian rhythm) – your body uses sunlight to time various important functions, such as when you wake up, so lower light levels during the winter may disrupt your body clock and lead to symptoms of seasonal affective disorder

It’s also possible that some people are more vulnerable to seasonal affective disorder as a result of their genes, as some cases appear to run in families.

Risk Factors for Seasonal affective disorder

As seasons change, there is a shift in our ‘biological internal clocks’ or circadian rhythms, due partly to these changes in sunlight patterns. This can cause our biological clocks to be out of ‘step’ with our daily schedules. The most difficult months for seasonal affective disorder sufferers are January and February (northern hemisphere) and July and August (southern hemisphere). Younger persons and women are at higher risk.

Factors that may increase your risk of seasonal affective disorder include:

• Family history. People with seasonal affective disorder may be more likely to have blood relatives with SAD or another form of depression.
• Having major depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.
• Living far from the equator. Seasonal affective disorder appears to be more common among people who live far north or south of the equator. This may be due to decreased sunlight during the winter and longer days during the summer months.

Seasonal affective disorder symptoms

The symptoms of seasonal affective disorder (SAD) are similar to those of normal depression, but they occur repetitively at a particular time of year.

Seasonal affective disorder (SAD) usually start in the fall or early winter and and go away during the sunnier days of spring and summer. Less commonly, people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses.

The nature and severity of seasonal affective disorder varies from person to person. Some people just find the condition a bit irritating, while for others it can be severe and have a significant impact on their day-to-day life.

Depression

Most people with seasonal affective disorder will feel depressed during the autumn and winter.

Signs that you may be depressed include:

• a persistent low mood
• a loss of pleasure or interest in normal everyday activities
• feeling irritable
• feelings of despair, guilt and worthlessness
• low self-esteem
• tearfulness
• feeling stressed or anxious
• a reduced sex drive
• becoming less sociable

A small number of people will experience these symptoms in phases that are separated by “manic” periods where they feel happy, energetic and much more sociable.

Fall and winter SAD

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:

• Oversleeping
• Appetite changes, especially a craving for foods high in carbohydrates
• Weight gain
• Tiredness or low energy

Spring and summer SAD

Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:

• Trouble sleeping (insomnia)
• Poor appetite
• Weight loss
• Agitation or anxiety

Seasonal changes in bipolar disorder

In some people with bipolar disorder, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), and fall and winter can be a time of depression.

Other symptoms

In addition to symptoms of depression, you may also:

• be less active than normal
• feel lethargic (lacking in energy) and sleepy during the day
• sleep for longer than normal and find it hard to get up in the morning
• find it difficult to concentrate
• have an increased appetite – some people have a particular craving for foods containing lots of carbohydrates and end up gaining weight as a result

These symptoms may make everyday activities increasingly difficult.

Seasonal affective disorder diagnosis

Visit your doctor if you have symptoms of seasonal affective disorder (SAD). Effective treatments are available if you’re diagnosed with the condition.

Your doctor may carry out a psychological assessment to check your mental health. They may ask about:

• your mood
• your lifestyle
• your eating and sleeping patterns
• any seasonal changes in your thoughts and behavior
• whether your symptoms prevent you from carrying out normal activities
• whether there’s anything in your personal history that may contribute to a depressive disorder, such as child abuse
• whether there’s anything in your family history that may contribute to a depressive disorder, such as a family history of depression

Your doctor may also carry out a brief physical examination.

Confirming a diagnosis of seasonal affective disorder

Seasonal affective disorder can be difficult to diagnose because there are many other types of depression that have similar symptoms.

It may therefore take several years before you and your doctor realize that your symptoms are forming a regular pattern.

A diagnosis of seasonal affective disorder can usually be confirmed if:

• your depression occurs at a similar time each year
• the periods of depression are followed by periods without depression
• you’ve had symptoms during the same time of year for two or more years in a row.

Seasonal affective disorder treatment

A range of treatments are available for seasonal affective disorder, including cognitive behavioural therapy, antidepressants and light therapy. Your doctor will recommend the most suitable treatment option for you, based on the nature and severity of your symptoms. This may involve using a combination of treatments to get the best results.

The main treatments are:

• Lifestyle measures – including getting as much natural sunlight as possible, exercising regularly and managing your stress levels
• Seasonal affective disorder light therapy – where a special lamp called a light box is used to simulate exposure to sunlight
• Psychotherapy – such as cognitive behavioral therapy (CBT) or counseling
• Antidepressant medication – such as selective serotonin reuptake inhibitors (SSRIs)
• Mind-body connection: Examples of mind-body techniques that some people may choose to try to help cope with SAD include:
  • Relaxation techniques such as yoga or tai chi
  • Meditation
  • Guided imagery
  • Music or art therapy

The National Institute for Health and Care Excellence ¹⁾ recommends that SAD should be treated in the same way as other types of depression.

This includes using talking treatments such as cognitive behavioural therapy (CBT) or medication such as antidepressants.

Light therapy is also a popular treatment for SAD, although NICE says it’s not clear whether it’s effective.

Things you can try yourself

There are a number of simple things you can try that may help improve your symptoms, including:

• try to get as much natural sunlight as possible – even a brief lunchtime walk can be beneficial
• make your work and home environments as light and airy as possible
• sit near windows when you’re indoors
• take plenty of regular exercise, particularly outdoors and in daylight – read more about exercise for depression
• eat a healthy, balanced diet
• if possible, avoid stressful situations and take steps to manage stress

It can also be helpful to talk to your family and friends about seasonal affective disorder, so they understand how your mood changes during the winter. This can help them to support you more effectively.

In addition to your treatment plan for seasonal affective disorder:

• Make your environment sunnier and brighter. Open blinds, trim tree branches that block sunlight or add skylights to your home. Sit closer to bright windows while at home or in the office.
• Get outside. Take a long walk, eat lunch at a nearby park, or simply sit on a bench and soak up the sun. Even on cold or cloudy days, outdoor light can help — especially if you spend some time outside within two hours of getting up in the morning.
• Exercise regularly. Exercise and other types of physical activity help relieve stress and anxiety, both of which can increase seasonal affective disorder symptoms. Being more fit can make you feel better about yourself, too, which can lift your mood.

Alternative medicine

Certain herbal remedies, supplements or mind-body techniques are sometimes used to try to relieve depression symptoms, though it’s not clear how effective these treatments are for seasonal affective disorder.

Herbal remedies and dietary supplements aren’t monitored by the Food and Drug Administration (FDA) the same way medications are, so you can’t always be certain of what you’re getting and whether it’s safe. Also, because some herbal and dietary supplements can interfere with prescription medications or cause dangerous interactions, talk to your doctor or pharmacist before taking any supplements.

Make sure you understand the risks as well as possible benefits if you pursue alternative or complementary therapy. When it comes to depression, alternative treatments aren’t a substitute for medical care.

Coping and support

These steps can help you manage seasonal affective disorder:

• Stick to your treatment plan. Follow your treatment plan and attend therapy appointments when scheduled.
• Take care of yourself. Get enough sleep to help you feel rested, but be careful not to get too much rest, as seasonal affective disorder symptoms often lead people to feel like hibernating. Participate in an exercise program or engage in another form of regular physical activity. Make healthy choices for meals and snacks. Don’t turn to alcohol or recreational drugs for relief.
• Practice stress management. Learn techniques to manage your stress better. Unmanaged stress can lead to depression, overeating, or other unhealthy thoughts and behaviors.
• Socialize. When you’re feeling down, it can be hard to be social. Make an effort to connect with people you enjoy being around. They can offer support, a shoulder to cry on or shared laughter to give you a little boost.
• Take a trip. If possible, take winter vacations in sunny, warm locations if you have winter seasonal affective disorder or to cooler locations if you have summer seasonal affective disorder.

Psychosocial treatments

Psychosocial treatments focus on both psychological aspects (how your brain functions) and social aspects (how you interact with others). Some possible psychosocial treatments are described below.

Cognitive behavioural therapy

Cognitive behavioural therapy (CBT) is based on the idea that the way we think and behave affects the way we feel. Changing the way you think about situations and what you do about them can help you feel better.

Cognitive behavioural therapy (CBT) is based on the concept that your thoughts, feelings, physical sensations and actions are interconnected, and that negative thoughts and feelings can trap you in a vicious cycle.

Cognitive behavioural therapy (CBT) aims to help you deal with overwhelming problems in a more positive way by breaking them down into smaller parts. You’re shown how to change these negative patterns to improve the way you feel.

Unlike some other talking treatments, CBT deals with your current problems, rather than focusing on issues from your past. It looks for practical ways to improve your state of mind on a daily basis.

If you have CBT, you’ll have a number of sessions with a specially trained therapist, usually over several weeks or months. Your programme could be:

• an individual programme of self-help
• a programme designed for you and your partner (if your depression is affecting your relationship)
• a group programme that you complete with other people in a similar situation
• a computer-based CBT programme that’s tailored to your needs and supported by a trained therapist

Counseling and psychodynamic psychotherapy

Counseling is another type of talking therapy that involves talking to a trained counselor about your worries and problems.

During psychodynamic psychotherapy you discuss how you feel about yourself and others and talk about experiences in your past. The aim of the sessions is to find out whether anything in your past is affecting how you feel today.

It’s not clear exactly how effective these two therapies are in treating depression.

Antidepressants

Antidepressants are often prescribed to treat depression and are also sometimes used to treat severe cases of seasonal affective disorder, although the evidence to suggest they’re effective in treating seasonal affective disorder is limited.

Antidepressants are thought to be most effective if taken at the start of winter before symptoms appear, and continued until spring.

Selective serotonin reuptake inhibitors (SSRIs) are the preferred type of antidepressant for treating seasonal affective disorder. They increase the level of the hormone serotonin in your brain, which can help lift your mood.

If you’re prescribed antidepressants, you should be aware that:

• it can take up to four to six weeks for the medication to take full effect
• you should take the medication as prescribed and continue taking it until advised to gradually stop by your doctor
• some antidepressants have side effects and may interact with other types of medication you’re taking

Common side effects of SSRIs include feeling agitated, shaky or anxious, an upset stomach and diarrhoea or constipation. Check the information leaflet that comes with your medication for a full list of possible side effects.

Seasonal affective disorder light therapy

Some people with seasonal affective disorder find that light therapy can help improve their mood considerably. This involves sitting by a special lamp called a light box, usually for around 30 minutes to an hour each morning.

Light boxes come in a variety of designs, including desk lamps and wall-mounted fixtures. They produce a very bright light. The intensity of the light is measured in lux – the higher lux, the brighter the light.

Dawn-stimulating alarm clocks, which gradually light up your bedroom as you wake up, may also be useful for some people.

The light produced by the light box simulates the sunlight that’s missing during the darker winter months.

It’s thought the light may improve seasonal affective disorder by encouraging your brain to reduce the production of melatonin (a hormone that makes you sleepy) and increase the production of serotonin (a hormone that affects your mood).

Who can use light therapy?

Most people can use light therapy safely. The recommended light boxes have filters that remove harmful ultraviolent (UV) rays, so there’s no risk of skin or eye damage for most people.

However, exposure to very bright light may not be suitable if you:

• have an eye condition or eye damage that makes your eyes particularly sensitive to light
• are taking medication that increases your sensitivity to light, such as certain antibiotics and antipsychotics, or the herbal supplement St. John’s Wort

Speak to your doctor if you’re unsure about the suitability of a particular product.

Does light therapy work?

There’s mixed evidence regarding the overall effectiveness of light therapy, but some studies have concluded it is effective, particularly if used first thing in the morning.

It’s thought that light therapy is best for producing short-term results. This means it may help relieve your symptoms when they occur, but you might still be affected by seasonal affective disorder next winter.

When light therapy has been found to help, most people noticed an improvement in their symptoms within a week or so.

Side effects of light therapy

It’s rare for people using light therapy to have side effects. However, some people may experience:

• agitation or irritability
• headaches or eye strain
• sleeping problems (avoiding light therapy during the evening may help prevent this)
• tiredness
• blurred vision

These side effects are usually mild and short-lived, but you should visit your doctor if you experience any particularly troublesome side effects while using light therapy.

Trying light therapy

You’ll need to buy one yourself if you want to try light therapy.

Before using a light box, you should check the manufacturer’s information and instructions regarding:

• whether the product is suitable for treating seasonal affective disorder
• the light intensity you should be using
• the recommended length of time you need to use the light

Make sure that you choose a light box that is medically approved for the treatment of seasonal affective disorder and produced by a fully certified manufacturer. The Seasonal Affective Disorder Association can provide you with a list of recommended manufacturers.