Seasonal Depression

Seasonal Affective Disorder (SAD)

Seasonal affective disorder (sometimes abbreviated to SAD) is also known as "winter depression". It has most impact between the months of September and April, and particularly during the midwinter months, November to January.

In most cases it is associated with fairly mild symptoms of depression, and often remains undiagnosed, but in more severe forms it can be seriously disabling.

The symptoms are very similar to depression, though with particular emphasis on sleep and eating problems. You may find yourself eating more or sleeping more when the temperature drops and darkness falls earlier. While those are common and normal reactions to the changing seasons, people with seasonal affective disorder (SAD) experience a much more serious reaction when summer shifts to fall and on to winter.

People with seasonal depression are often fatigued and tend to oversleep, although some suffer disturbed sleep. There is also a tendency to over eat and put on weight.

Symptoms of Seasonal Depression

Seasonal affective disorder is a cyclic, seasonal condition. This means that signs and symptoms usually come back and go away at the same times every year. Usually, seasonal affective disorder symptoms appear during late fall or early winter and go away during the warmer, sunnier days of spring and summer. 

But some people have the opposite pattern, developing seasonal affective disorder with the onset of spring or summer. In either case, problems may start out mild and become more severe as the season progresses.

Fall and winter SAD (winter depression)

Symptoms of winter-onset seasonal affective disorder include:

• Depression
• Hopelessness
• Anxiety
• Loss of energy
• Social withdrawal
• Oversleeping
• Loss of interest in activities you once enjoyed
• Appetite changes, especially a craving for foods high in carbohydrates
• Weight gain
• Difficulty concentrating and processing information

Test yourself

Spring and summer SAD (summer depression)

Symptoms of summer-onset seasonal affective disorder include:

• Anxiety
• Insomnia
• Irritability
• Agitation
• Weight loss
• Poor appetite
• Increased sex drive

Test yourself

What causes winter depression?

It is not entirely clear what causes winter depression, but it appears that daylight is the most important factor.

There is an interesting link between daylight and the level of serotonin in your brain, which as you surely know, is involved in controlling mood and emotions. When it is dark, a tiny gland in your brain called the pineal gland produces a hormone called melatonin. Melatonin is involved in making you sleep when it is dark. The important thing here is that the pineal gland uses serotonin to make melatonin.

It appears that if you have seasonal affective disorder, your melatonin levels are abnormally high during the winter months. As serotonin is used to make melatonin, these seasonal increase in melatonin may impair serotonin function.

In the same way as depression, it is thought that stressful life experiences and hormonal upheavals are amongst the triggers for seasonal depression.

How is it treated?

Often the first choice of treatment is light therapy (phototherapy). Phototherapy involves spending between 1 and 4 hours each day exposed to bright light, at least ten times brighter than an ordinary light bulb. It is important that you use a light box designed specifically for this purpose, in order to avoid exposure to dangerous levels of ultraviolet (UV) light. A sunbed, for example, is not suitable for this purpose.

Phototherapy is effective in approximately 4 out of 5 people.

You may experience some headaches or irritability whilst having a course of phototherapy and it is important that you have your eyes checked regularly, but the side-effects are generally mild and rare compared with those you might experience with antidepressants. Once your treatment is well established and if it is working effectively, you may not need to use the light source every day.

There are a number of other things you can do to help yourself overcome seasonal depression, such as

• getting plenty of exercise
• eating well 
• spending as much time outdoors as possible
• sitting near a window when you are indoors
• avoid oversleeping, reduce your sleep to 8 hours a day.

Related pages in this site:

Help for Seasonal Affective Disorder

Are you suffering from depression? Or somebody in the family?

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