Seasonal affective disorder (SAD) is a type of depression that's related to changes in seasons — SAD begins and ends at about the same times every year. If you're like most people with SAD , your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody

Seasonal Affective Disorder
Some people experience a serious mood change during the winter months, when there is less natural sunlight. This condition is called seasonal affective disorder, or SAD. SAD is a type of depression. It usually lifts during spring and summer.

"In people who have Seasonal Affective Disorder, the brain has difficulty regulating serotonin, a neurotransmitter that is believed to be responsible for balancing mood. These difficulties are exacerbated when the body has less exposure to sunlight, as occurs during the shorter days of winter. At this point, the lack of sunlight leads to depleted levels of serotonin in the parts of the brain where it can boost the mood, leading to depression. In addition to seasonal changes of serotonin levels for individuals affected by SAD." source

Not everyone with SAD has the same symptoms. They include

Sad, anxious, or "empty" feelings
Feelings of hopelessness and/or pessimism
Feelings of guilt, worthlessness or helplessness
Irritability, restlessness
Loss of interest or pleasure in activities you used to enjoy
Fatigue and decreased energy
Difficulty concentrating, remembering details and making decisions
Difficulty sleeping or oversleeping
Changes in weight
Thoughts of death or suicide

Get Help SAD may be effectively treated with light therapy

From green light soothing the pain of migraine, to blue light reducing organ damage during surgery, recent small studies have uncovered some intriguing effects of this therapy. But apart from easing seasonal affective disorder, we’ve been slow to embrace light as a serious contender for treating neurological conditions.

"We’ve known for 15 years that a special kind of receptor in our eyes transmits information directly to the body’s master clock, as well as other brain areas that control mood and alertness. These cells are particularly responsive to bluish light, including sunlight.

These receptors enable light to act as a powerful reset switch, keeping the clock in our brain synced to the outside world. But this clock can fall out of sync or weaken as part of ageing or a range of disorders – a problem doctors are now starting to treat with light. Read more:

"Because of its link with lack of sunlight, one of the most common treatments for SAD is light therapy. This can take the form of regular use of a light box that produces bright, blue-enriched light. Increased exposure to natural sunlight can help too – indeed, exposure to sunlight soon after waking has been found to be as effective for general depression as antidepressant drugs.

Source:New Scientist

The Mayo clinic states Light therapy is a way to treat seasonal affective disorder (SAD) and certain other conditions by exposure to artificial light. SAD is a type of depression that occurs at a certain time each year, usually in the fall or winter.

During light therapy, you sit or work near a device called a light therapy box. The box gives off bright light that mimics natural outdoor light.

Light therapy is thought to affect brain chemicals linked to mood and sleep, easing SAD symptoms. Using a light therapy box may also help with other types of depression, sleep disorders and other conditions. Light therapy is also known as bright light therapy or phototherapy.

You may want to try light therapy for a number of reasons:

Your doctor recommends it for seasonal affective disorder or another condition.
You want to try treatment that is safe and has few side effects.
You want to increase the effectiveness of antidepressant medication or mental health counseling (psychotherapy).
You need to avoid antidepressant medications during pregnancy or while breast-feeding.
It may allow you to take a lower dose of antidepressant medication. Source

SAD Therapy Light 12000 Lux Twin Color: White and Warm white Dimmer Timer Control Auto shut down Certification: CE Certification: FCC Certification: ROHS Warranty: 1 Year