Seasonal Affective Disorder is a depression that many people experience during the winter months, particularly in the Northern Hemisphere.

Often referred to as seasonal depression, Seasonal Affective Disorder was discovered in the early eighties by the National Institute of Health in the US.

Seasonal Affective Disorder causes you to feel down, gloomy, and lose energy. You may have difficulty concentrating and feeling alert, withdraw socially and have carbohydrate cravings. Seasonal Affective Disorder sufferers also experience sleep problems.

The NIH estimates that over 36 million Americans suffer depressive symptoms brought on by the winter months. Although not as prevalent in Australia it is still estimated that 1 in 300 Australians experience SAD.

Seasonal Affective Disorder vs. Winter Blues

Although often confused with the ‘winter blues,’ Seasonal Affective Disorder and Winter Blues are not the same.

Seasonal Affective Disorder is manifested by symptoms of clinical depression, with impaired social interaction and cognitive ability. On the other hand, Winter Blues is milder than SAD and is typified by the lack of energy and feeling sad or down.

If you have the winter blues, you can still function. If you have Seasonal Affective Disorder, normal daily functions are difficult to perform.

Although Seasonal Affective Disorder and Winter Blues differ in the degree of severity, the treatment is the same for both conditions.

What causes Seasonal Affective Disorder?

Researchers agree that the lack of sunlight in Autumn and winter causes the effects of seasonal depression. Without sunlight, the brain doesn't produce enough serotonin, which results in the symptoms of depression. The darker days also signal the brain to overproduce the hibernation hormone, melatonin. The symptoms diminish as the days get longer, although many Seasonal Affective Disorder sufferers note brief (1-2 week) periods of SAD-like symptoms in the summer.

Symtoms often include fatigue, weight gain, sleep problems such as insomnia and hypersomnia, mood swings, introversion and food cravings. The problem many doctors have in diagnosing SAD is the symptoms overlap with many sleep disorders and other forms of depression.

More information Why some people are affected and others are not

Seasonal Affective Disorder Treatment

Light Therapy

Since the discovery of Seasonal Affective Disorder (SAD) in 1984, light therapy has been recommended as the treatment of choice.

In studies, over 80% of those who used light recovered quickly — usually within 2 weeks. Other treatments, although successful, require more time and some, such as antidepressant medication cause long-term side effects. However, there are still some sufferers who do not respond well to light therapy, and these individuals need to consider another or a combined approach.

During the last 20 years, over 4,000 studies involving tens of thousands of patients have demonstrated the superiority of light for treating Seasonal Affective Disorder and related circadian rhythm disorders.

The NIH has demonstrated that specialised blue light to be the most effective means of reversing the effects of this winter depression. Light therapy produces serotonin in the brain, and researchers have shown low serotonin levels contribute to depression.

Since this discovery, scientists have successfully used bright light to treat non-seasonal depression as well as other mood disorders.

Light also suppresses the hibernation hormone melatonin. This is important, because melatonin forces us to pull back, conserve and sleep. Melatonin secretion is necessary during the night, but daytime melatonin can be harmful. By suppressing melatonin during the daytime, our activity cycle is extended, and we actually sleep better at night.

Scientists agree that Seasonal Affective Disorder and related problems result from the lack of light and patients respond to light therapy much quicker than any other treatment.

Only 15 minutes/day is needed to maintain the antidepressant effect, and light can be used while doing other activities such as getting ready in the morning, eating breakfast, or watching TV.

Light therapy is preferred because it works naturally and addresses the core problem that the lack of light causes. Light not only suppresses the winter, withdrawal hormones, but it produces active mood hormones and resets the sleep/wake cycle.

Disadvantages
Although the vast majority of people respond to light, not every one does, and of those who do respond, some do not feel completely better with light alone. Some people may also find light therapy inconvenient, as it requires 15-20 minutes each day.

Side Effects
No long-term negative side effects have been documented from using light therapy. Short-term side effects are uncommon, but include headache from eyestrain, nausea, agitation or nervousness. In almost all cases, side effects are quickly mitigated by allowing the eyes to gradually adjust to the light. Increasing the distance one sits away from the light as well as increasing the background lighting should minimize any potential side effects.

Other Treatments

Light resets Circadian Rhythms

Scientists believe that Seasonal Affective Disorder is associated with shifted circadian rhythms (i.e. body clock). The body clock regulates our daily activity cycles, and it needs bright light signals to reset itself each day. When it doesn't receive this signal, it can malfunction. This can affect how you sleep and feel during the day. If you have difficulty waking up, or you fall asleep and wake up at the wrong time, you may have a circadian rhythm disorder.

Body clock Assessment tool

You can now take a test to see if you have a circadian rhythm disorder. The assessment tool will let you know which circadian rhythm disorder you may have as well as its degree of severity. Since our body clocks react differently, this assessment tool will also develop a customized treatment schedule so you can respond as quickly as possible.

Frequently Asked Questions

Getting the best treatment

Research Articles

Light Therapy And Fluoxetine (Prozac) Are Equally Effective Seasonal Affective Disorder

Consensus Guidelines for Seasonal Affective Disorder Treatment