Many people tend to feel a little “blue” in the late fall and winter, as shorter days and inclement weather make outdoor activities less enjoyable. In some cases, seasonal depression can take the form of a more serious condition known as seasonal affective disorder, or SAD.

Symptoms of SAD may include mild to moderate depression or anxiety, which may be quite debilitating. People who work long hours in office buildings with few windows can actually experience symptoms of SAD year round. For others, long stretches of cloudy, overcast weather can spur symptoms of seasonal affective disorder.

If you feel “down” for days or even weeks at a time, or you can’t motivate yourself to do your normal, otherwise enjoyable activities, you may be suffering from seasonal affective disorder, a form of depression that can dramatically impact your daily life. Fortunately, many treatment options are at your disposal.

SAD Causes and Risk Factors

Although its exact cause is still unknown, seasonal affective disorder has been linked to a chemical imbalance in the brain triggered by shorter daylight hours and the relative lack of sunshine in winter. Reduced sunlight can reduce levels of serotonin, a neurotransmitter that affects mood, which can lead to seasonal depression.

Some medical researchers suspect that changes in levels of melatonin, a hormone that regulates sleep patterns and mood, contribute to seasonal affective disorder.

Other risk factors for seasonal depression include:

  • Family history: SAD sufferers are likely to have relatives with the condition.
  • Gender: Female SAD sufferers seem to outnumber their male counterparts.
  • Geography: Living far from the equator, where there is less sunlight in winter, increases SAD risk.

Researchers also believe that the change of seasons can disrupt our internal clocks that let us know when we should be awake or asleep. This disruption of our circadian rhythm may lead to seasonal depression.

Symptoms of SAD

The defining characteristic of SAD is its cyclical, seasonal nature; symptoms of SAD tend to appear and disappear at the same time every year. Most seasonal affective disorder sufferers experience the symptoms of SAD in late fall and winter. These effects gradually disappear as the warmer, more sun-filled days of spring and summer return.

People with SAD may experience any number of the following symptoms:

  • Anxiety
  • Appetite changes
  • Depression
  • Difficulty concentrating
  • Hopelessness
  • Loss of energy
  • Loss of interest in normally enjoyed activities
  • Oversleeping
  • Social withdrawal
  • Weight gain.

In a small number of cases, the onset of seasonal affective disorder occurs in the summer instead of the fall or winter. Some scientists believe that this form of seasonal depression may be a response to high heat and humidity. In cases of summer-onset seasonal depression, the symptoms of SAD include insomnia, anxiety and weight loss due to decreased appetite.


American Psychiatric Association. (2010). Seasonal affective disorder. Retrieved July 10, 2010, from

Family Doctor. (2010). Seasonal affective disorder. Retrieved July 10, 2010, from

Mayo Clinic. (2007). Seasonal affective disorder (SAD). Retrieved July 10, 2010, from

 Posted on : June 11, 2014