Seasonal Affective

Seasonal affective disorder (SAD) is a type of depression that is related to the change of seasons but is predominant in the fall/winter months. It can occur in tandem with either major depression or manic depression (bipolar disorder).
The onset of SAD usually occurs during adulthood (average age of 23), and it is four times more likely to affect women than men. Individuals living in northern climates are especially affected. A diagnosis of SAD is considered when depressive symptoms occur at about the same time each year and have persisted for at least two years.
Causes of SAD
In the fall/winter months, decreased exposure to sunlight can interrupt your biological clock and lead to the depression that characterizes SAD. Related declines in the brain chemical serotonin (which affects mood) and melatonin (which influences sleep) may be implicated. The cause of spring-onset SAD is unclear.
Symptoms of SAD
Two seasonal patterns of SAD symptoms have been identified. 
  • Fall-onset type (‘winter depression’), or classic SAD, occurs with major depressive episodes that begin in the late fall to early winter months and remit during the summer months.
  • Spring-onset type (‘summer depression’) SAD is characterized by severe depressive episodes that begin in late spring to early summer.

Individuals may experience different symptoms of SAD that include the following
  • Increased sleeping
  • Daytime drowsiness
  • Irritability
  • Fatigue or low energy level
  • Decreased sex drive
  • Diminished concentration
  • Difficulty thinking clearly
  • Weight gain

The symptoms of SAD may resemble those of other psychiatric conditions.

Diagnosing SAD
Your doctor will perform a thorough physical exam, obtain a medical and social history and conduct a careful psychiatric evaluation to diagnose SAD. Laboratory or other tests may be needed to rule out any underlying causes of depression.
Treating SAD
Treatment can differ for fall-onset and spring-onset depression but will include one or more of the following approaches.
  • Light therapy (phototherapy) consists of exposure to bright light that mimics natural outdoor light.
  • Antidepressant medications can help relieve the symptoms associated with SAD.
  • Psychotherapy (“talk” therapy) may be useful in identifying and eliminating negative behaviors, managing stress and helping you cope with SAD.

A number of steps can be taken to help alleviate some of the symptoms of SAD.
  • Expose yourself to natural light as much as possible .
  • Set realistic goals with the depression in mind and assume a reasonable amount of responsibility.
  • Break large tasks into small ones, set some priorities and do what you can as you can.
  • Try to be with other people and to confide in someone; it is usually better than being alone and secretive.
  • Participate in activities that may make you feel better.
  • Mild exercise, going to a movie or a ball game, or participating in religious, social, or other activities may help


Our physicians at Houston Methodist specialize in managing seasonal affective disorder at the following convenient locations: