SAD (seasonal affective disorder) is a subtype of depression.
Also known as SAD, it is sometimes referred to as winter depression. As winter approaches, the mornings start later and the evenings begin earlier, so there is less sunlight each day. Experts say SAD is most likely caused by lack of sunlight alone and not by cold temperatures.
Depressive symptoms usually build up slowly as days start getting shorter, and they gradually subside in early spring, as the amount of sunlight rises each day.
Contents of this article:
- SAD did not receive a clinical name until the early 1980s.
- The symptoms of SAD are similar to those of depression.
- Common symptoms include low mood, lethargy, and social withdrawal.
What is SAD?
SAD was first mentioned in scientific literature in 1845 but the condition did not get a clinical name until the early 1980s.
We know that seasonal variations in sunlight have an impact on animal behavior, for example, hibernation, reproduction, and seeking out a mate. Seasonal changes in sunlight affect our circadian rhythms, which are also referred to as our internal biological clocks.
SAD is thought to affect 4-6 percent of people in the United States and is more common among young adults with onset typically between 20-30 years of age. It is often seen in females more than males, although depression is more common, generally, in females.
It also occurs more in areas that are further north. For example, it is seven times more common in Washington State than in Florida.
Interestingly, people can have SAD during the summer, although this is rare.
Symptoms of SAD
The signs and symptoms of SAD are similar to those of depression, but they come on as winter approaches and go away during springtime. In the majority of cases, symptoms come back each year at around the same time.
Symptoms are usually mild as autumn advances, and they worsen as the amount of daylight drops. The severity, characteristics, and patterns of SAD can vary considerably from person-to-person.
About four-fifths of people who experience SAD develop unipolar depression, while the rest have bipolar depression. Unipolar means they have persistent depressive symptoms, while bipolar involves swinging from high or manic periods to very low or depressive ones.
The signs and symptoms of SAD include:
- feeling guilty and worthless
- feeling stressed
- low moods and despair
- reduced libido
- lethargy, fatigue, hypersomnia
- increased appetite
- social withdrawal
- difficulty concentrating
- weight gain
Symptoms of spring and summer SAD
Insomnia is a common symptom of spring and summmer SAD.
Rather than feeling depressed during the winter, some people have symptoms in the spring and summer. This type of SAD is rare, but symptoms can include:
- low mood
- reduced appetite
- weight loss
Who has a higher risk of developing SAD?
There are factors that can affect who gets SAD and who is less likely to have the condition.
Sex - females are more likely than males to suffer from SAD, although this may be due to a greater prevalence of depression among women. Males may have more severe symptoms.
Geography - some studies suggest that the further someone lives from the equator, the higher the chances of developing SAD. Put simply, those who live in places where days are considerably shorter in winter are more susceptible.
Genetics - individuals with a close relative who has or had SAD have a greater risk.
Having, or having had depression - people with a history of depression or bipolar depression are more likely to develop SAD than those with no such history.
Causes of SAD
Experts are still unsure of the exact causes of SAD. However, studies have pointed to the following:
- Circadian rhythm - our body clock. Each of us has an internal body clock that tells us when to be awake and asleep. Less sunlight in the winter is thought to disrupt our circadian rhythm, causing depressive symptoms.
- Melatonin levels - melatonin is a hormone that influences our sleep patterns and mood. Experts believe that reduced exposure to sunlight through shorter days in winter disrupts our melatonin balance. People with SAD also have decreased serotonin levels during the winter months.
- The hypothalamus - sunlight is thought to stimulate the hypothalamus, a part of the brain that controls sleep, mood, and appetite, all of which impact on how we feel. Similarly, production of serotonin, a brain chemical (neurotransmitter) that affects mood, may be affected by low sunlight.
Diagnosis of SAD
The doctor may carry out a physical exam and ask questions covering:
- How long symptoms have been present, how severe they are, and how they affect daily activities.
- What eating patterns are like.
- General lifestyle questions.
- Sleeping patterns and if they have changed.
- How thoughts and behaviors change with the seasons.
- Details about family medical history, such as depression, SAD, etc.
As there are several types of depression, diagnosing SAD accurately may take time. There is no medical or laboratory test that can diagnose the condition. The doctor may order some diagnostic tests, including blood tests, to rule out other illnesses or underlying conditions.
The American Psychiatric Association do not class SAD as a separate disorder under the DSM-5 criteria, but a "course specifier." They refer to it as "depression with seasonal pattern."
Treatments for SAD
According to the American Psychiatric Association, people may alleviate SAD symptoms by boosting their exposure to sunlight. For example, going for long walks outdoors when there is still some sunlight could help.
The National Institute for Health and Care Excellence (NICE) in the United Kingdom recommend that SAD treatment should be the same as for other types of depression, involving psychosocial and antidepressant medication.
Bright light therapy
If symptoms are so severe that they affect a person's daily life, light therapy is sometimes recommended. Bright light therapy, also known as phototherapy, can help restore circadian rhythm.
With this kind of therapy, a person sits in front of a special light for 30-90 minutes each day. It is important to purchase a light box that is designed for treating SAD. UV lamps, full-spectrum lights, and tanning lamps will not do the same job.
In general, light therapy is required from 30 minutes to 2 hours per day, depending on the strength of the light. Doctors say exposure in the mornings tends to give the best results.
A similar treatment is known as dawn simulation when a special light in the bedroom is programmed to get slowly lighter in the mornings, to simulate dawn.
Experts say this type of phototherapy also helps restore brain chemistry balance. Nobody is sure how all this occurs.
Although SAD involves a change to a person's brain chemistry, therapy that focuses on mood and behavior can also help.
Cognitive behavioral therapy (CBT) is based on the premise that it is how a person thinks and reacts to things that causes unhappiness rather than the situation. For example, if the way a person perceives certain situations can be altered, their behavior will change, and their symptoms will be reduced.
CBT usually includes an individual program of self-help, and another for the person and their partner, if appropriate. Sometimes a group program can also be helpful.
A doctor may prescribe an antidepressant, usually a selective serotonin reuptake inhibitor (SSRI), which raises serotonin levels.
Antidepressants do not work straight away; they can take from 10 days to 1 month to work well. Experts say antidepressants for SAD are more effective if taken at the beginning of the SAD season, before symptoms appear. Usually, they are taken daily until springtime.
People should always follow their doctor's instruction when taking these drugs.
Some people have found that making their environment sunnier and brighter helps alleviate symptoms. Examples include opening blinds and curtains, trimming trees around the house, and sitting closer to the window during daytime.
Even in winter, the sun still comes up, and there is more sunlight outdoors than indoors. So, getting out every day for a long spell in the open air may help.
Similarly, exercise is not only good for the health but alleviates symptoms of anxiety and aids proper sleep. Exercises can also help people nurture a better self-image, which tends to lift their mood.