Healthy Living: Seasonal Affective Disorder 

By: Dr. David Prescott, Ph.D. 

Seasonal Depression Impacts Many People:  People who live in areas where daylight hours in winter are extremely short are more likely to be impacted by seasonal affective disorder, or seasonal depression.  According to the American Psychiatric Association, 10-20% of people in America feel more depressed with the onset of winter.   A true diagnosis of seasonal affective disorder is less common, with estimates ranging from around 1% to 10% of the population during the winter, partly depending on the latitude at which you live.


What are the Symptoms of Seasonal Affective Disorder?  The symptoms for seasonal depression are exactly the same as those for major depression.  As the name implies, the only difference with seasonal affective disorder is that the symptoms begin at roughly the same month for one or more consecutive years.  In Maine and other northern latitude locations, the most common time of onset is the fall. Common symptoms include:


  • persistently sad or irritable mood ( 2 or more consecutive weeks)
  • pronounced changes in sleep, appetite, and energy
  • difficulty thinking, concentrating, and remembering
  • lack of interest in or pleasure from activities that were once enjoyed
  • feelings of guilt, worthlessness, hopelessness, and emptiness
  • recurrent thoughts of death or suicide
  • persistent physical symptoms that do not respond to treatment, such as headaches, digestive disorders, and chronic pain


Is Seasonal Affective Disorder Caused by Lack of Sunlight?   While many researchers have studies the cause, or causes, of seasonal affective disorder, the exact relationship between sunlight and depression is not entirely clear.  However, there is relatively good data that people who live at far northern latitudes are at higher risk for seasonal affective disorder than those who live further south.  There also appears to be some degree of genetic predisposition to seasonal affective disorder.



What Treatments are Available for Seasonal Depression?


  • Light Therapy:  Light therapy (i.e., daily exposure to bright artificial light during the symptomatic months) is supported by research as an effective treatment for seasonal affective disorder.   Clinical practice guidelines for SAD recommend daily use of light therapy each year from onset of the first symptom until the time in the spring when SAD symptoms would naturally resolve on their own.


  • Cognitive-Behavioral Therapy:   Cognitive-behavioral therapy (CBT) is a type of psychotherapy that teaches clients to challenge unhelpful patterns of thinking and to engage in behaviors which counteract depression.   It is often helpful, in terms of reducing depression, to overcome the tendency to ‘hibernate’ during winter months, but to purposefully engage in activities every day.


  • Get a thorough medical evaluation:  Sometimes depression can be caused by another medical problem, like abnormal thyroid activity.  If you are more depressed and haven’t seen your primary care doctor, calling for a visit may be an important first step.


  • Exercise: The benefits of exercise for treating depression continue to accumulate.  As with other forms of depression, seasonal affective disorder is often well controlled through regular exercise.


  • Medication:  Some anti-depressant medications, such as Wellbutrin XL, have been FDA approved for treatment of seasonal affective disorder.  Your psychiatrist or primary care doctor can discuss a range of medical treatment options.


Where can I get more information?  Here are some web links to learn more!


American Psychological Association:  or


American Psychiatric Association: