SAD (Seasonal Affective Disorder) is a type of winter depression which affects
millions of people every winter between September and April, in particular
during the months from September through to March or even later depending on light levels and
is recognised by Doctors and
Psychiatrists as a medical condition . SAD is caused by a biochemical imbalance
in the hypothalamus due to the shortening of daylight hours and the lack of
sunlight in winter. For many people SAD is a seriously disabling illness,
preventing them from functioning normally without continuous medical treatment.
For others, it is a milder condition, causing discomfort and find they eat and sleep slightly more in winter and
dislike the dark mornings and short days and this is commonly referred to as sub-syndromal SAD
or winter blues. It is estimated that a staggering half of the UK population
have this milder form of condition. There is also a rare reverse form of SAD,
known as summer SAD, where symptoms occur each summer and remit in winter.
In the beginning man only worked and lived outdoors in
full natural daylight. At the turn of the 19th century 75% of the population
worked outdoors. Now less than 10% of the population work in natural outdoor
light. This change has resulted in a dramatic increase in light deficiency
symptoms of SAD can vary from person to person, and are similar to those that
develop in other types of depression. For more information, see Related topics.
The most common symptoms include:
Sleep problems - a desire to oversleep and difficulty staying awake, cannot get
out of bed, needing a nap in the afternoon, disturbed sleep and early morning
Overeating - a craving for carbohydrates and sweet foods, usually resulting in
Social problems - irritability and desire to avoid social contact
Loss of Libido - a decreased interest in sex and physical contact
Lethargy - too tired to cope, fatigue, often incapacitating, making it very
difficult or impossible to carry out normal routines
Physical symptoms - often joint pain or stomach problems, lowered resistance to
Cognitive Function - Difficulty with concentration and memory, the brain
does not work as well, or as quickly
- Low mood, worse than and different from normal sadness, misery, guilt,
loss of self-esteem, negative thoughts and feelings sometimes hopelessness and
despair, apathy and inability to carry out normal routine
- Tension, Stress is harder to deal with especially in young people
Sudden Mood Changes in Spring - Sharp change in mood, Some experience agitation and
restlessness and/or a short period of hypomania (over activity), no dramatic
mood change but a gradual loss of winter symptoms
One of the most important
distinguishing features of SAD is that it is highly seasonal. SAD symptoms
usually reoccur regularly each winter, starting between September and November
and continuing until March or April; a diagnosis can be made after 2 or more
consecutive winters of symptoms. In sub-syndromal SAD, symptoms such as
tiredness, lethargy, sleep and eating problems occur, but depression and anxiety
are absent or mild.
symptoms disappear in spring, either suddenly with a few weeks of
hypomania/hyperactivity, or gradually, depending on the intensity of sunlight
in the spring/early summer. In summer SAD, symptoms may be related to excessive
heat rather than light and may include irritability and lethargy rather than
oversleeping and overeating.
What Causes S.A.D
SAD is related to changes in the amount of daylight during the autumn and winter. Researchers have proved that bright light makes a difference to the brain chemistry but why some people suffer and others don't is not clear.
Scientists and doctors worldwide have been researching SAD since the early 1980s, and there are several different theories as to what causes it and where the problem lies. They mostly centre on the way that light triggers messages to part of the brain called the hypothalamus, which controls sleep, mood and appetite.
Low serotonin levels
Neurotransmitters (brain chemicals) carry the messages to the brain. There are several neurotransmitters involved in SAD, but the main one is serotonin. Levels of serotonin have been found to be lower in depressed people, in winter. It's thought that this neurotransmitter might not work properly in people with SAD.
High melatonin levels
After reaching the hypothalamus, nerve impulses travel to a tiny organ behind it called the pineal gland. While it's dark, the gland produces the hormone melatonin, which makes us sleep. Light stops melatonin production, so we wake up.
People with SAD have been found to 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 hypothalamus region of 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.
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.
SAD shows no discrimination.
It affects everyone without any regard to class,
race or occupation.
occurs throughout the northern and southern hemispheres but is rare in those
living within 30 degrees of the Equator, where daylight hours are long,
constant and extremely bright.
SAD affects both sexes. But it was found to affect
women more than men.
may begin at any age, but the main age of onset is 18-30. Children and adolescents are also vulnerable
SAD may be hereditary. Many SAD sufferers come from
a family where a parent or a close relative suffer from SAD.
In U.K, Europe, Australia and Canada, doctors estimate
that five percent of the population suffer from SAD. It is estimated that ten
percent of the population in the USA suffer from SAD. Across the world the incidence increases with distance from the
equator, except where there is snow on the ground, when it becomes less common.
Children with Seasonal Affective Disorder
Children with SAD often suffer from
fatigue and irritability, but not necessarily depression. They are generally
aware that something is wrong, very often, they will blame their problem on
external factors such as someone is "picking on them" Usually, these
symptoms are thought to be the result of the onset of puberty or of
adolescence. Keep an eye on your children to see whether they experience a
seasonal decline in academic achievement, activity or mood.
children with SAD suffer the following symptoms during the autumn and/or winter
Some will show symptoms such as:
Sleep problems, disturbed sleep,
tendency to fall asleep during the day
Increase in appetite
Carbohydrate or junk food cravings
Keep an eye for the following tell-tale signs of the performance at
Decline in academic achievements
Loss of desire to take part in
activities, especially sports
Poor organizational skills
Difficulty in writing
Children suffering from SAD may also show behavioural difficulties such
Withdrawal from family and friends
Tendency to watch a lot of television
without retaining what is seen
In springtime become hypomanic with
feelings of elation, talkativeness, sleepless nights and hyperactivity.
Children suffering from SAD is treated the same way as adults
Your GP is a good first point of contact. He or she
will ask about your day-to-day life and symptoms. One bout of the "winter
blues" doesn't automatically mean you have SAD. But, if you have regular
symptoms over three or more consecutive years in autumn/winter which clear in
the spring, the diagnosis may be SAD.
GP may also want to rule out other forms of depression.
What you should know about SAD and Winter Blues:
Another name for the winter blues is?
Seasonal affective disorder (SAD)
The full name for the winter blues is sub-syndromal seasonal affective disorder, a milder version of SAD, but they have common symptoms. It's also known as winter depression.
How many people are affected by the winter blues?
17 per cent
It is estimated that around three per cent of people suffer from severe winter depression, but up to 17 per cent of us experience the winter blues.
The winter blues is most common in:
According to the Royal College of Psychiatrists, SAD is around three times more common in women than men, and is rare in children and elderly people.
How does SAD differ from normal (non-seasonal) depression?
You sleep more
You crave carbohydrates
You eat more
People who suffer from non-seasonal depression often have difficulty sleeping and lose weight. A craving for sugary foods and carbohydrates is common with SAD.
What is thought to trigger SAD?
Lack of daylight
SAD is thought to be linked to the shorter days and lack of daylight associated with autumn and winter.
Which of the following can help lessen the symptoms of SAD?
A regular sleep pattern
Antidepressants, talking therapy and maintaining a healthy diet rich in fruit and vegetables can also help. People with SAD are usually advised to get outside in the daylight hours as much as possible, even if they don't feel like it.
People with SAD often have raised levels of which hormone?
People with SAD often have raised levels of the sleep hormone melatonin, which, in the winter months, makes them feel more sleepy than usual. However, this returns to normal in the summer months.
Which region of the brain has been associated with SAD?
A lack of sunlight is thought to affect the hypothalamus, leading to a hormonal imbalance, although it's not known why it affects some more than others. The hypothalamus controls mood, appetite and sleep.
What is the minimum light intensity needed to treat SAD?
Ordinary domestic lighting, with an intensity of around 200-500 lux, is not strong enough to treat SAD. The light on a bright sunny day can be 100,000 lux.
SAD and the winter blues is more common in northern latitudes