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Self-Help Information: Seasonal Affective Disorder or Winter Depression 

What is SAD?

Do you find yourself dreading the long nights and short days of winter?

Do you find that you sleep longer but have less energy during that time? Do you snack more and gain weight during the longer winter evenings? If so, you may suffer from Seasonal Affective Disorder (SAD) or winter depression. In its broadest sense, SAD encompasses anyone who has distinct depressions associated with the seasons. Although there are people who suffer from summer depression (the closer one gets to the equator, the more people say they dislike summer), in the northern US, the vast majority complain of winter depression.

Most people (over 90%) experience some difference in mood, energy or behavior with the change of seasons (called seasonality). For example, many people prefer sunny days to dark, cloudy ones and report a decrease in activity level in winter. Indeed, almost half of all people in the northern US report that they feel worse during the winter, with January and February typically experienced as the worst. In most individuals, these changes do not cause problems. However, in about six percent of the US population, this seasonality is severe enough to cause a great deal of distress and difficulties in functioning and qualifies for a diagnosis of SAD. Another 14% may suffer to a lesser degree (Rosenthal, 1998). These numbers are averages. In general, the further north you go, the more people are affected.

What are the Causes?

The primary culprit in SAD appears to be light deprivation. There are a variety of situations which can cause light deprivation, the most common being winter in a northern climate where there are fewer hours of daylight. Other factors include the level of light and windows available at work and at home and the weather pattern (sunny vs. gray or foggy days). While we do not know for sure the cause of SAD, it appears that melatonin, a sleep-related hormone secreted by the pineal gland in the brain, may be involved. When it is dark, the production of melatonin (which may cause symptoms of depression) is increased.

There are other contributing factors to SAD. Stressful events may trigger feelings of depression in winter. As with many illnesses, we are more vulnerable when we are stressed. In addition, it appears that some people are simply more vulnerable to SAD than others. SAD tends to run in families and most individuals with SAD have a close relative with some type of depression (frequently SAD). Thus, there appears to be a genetic vulnerability to SAD, perhaps connected to a general vulnerability to depression.

What are the Symptoms of SAD?

SAD is a form of depression so the symptoms are similar to depression in general. The main distinguishing feature from other types of depression is "seasonality" or a consistent pattern of mood changes in relation to the seasons of the year. The most common symptoms are:

  • Depression (sad, anxious or empty moods)
  • Decreased energy
  • Change in appetite (especially a craving for sweet or starchy foods)
  • Weight gain
  • Increased need for sleep
  • Avoidance of social situations
  • Level of Seasonality

    To determine is you suffer from SAD, fill out the chart below by putting an X in the appropriate column for all applicable months. Consider your pattern over the past three years.














    No Change

    Feel best

    Lose most weight

    Socialize most

    Sleep least

    Eat least

    Gain most weight

    Socialize least

    Feel worst

    Eat most

    Sleep most

    Examine your chart. Compare the first five symptoms on the list with the bottom five and look for a pattern. How consistent is the pattern? Are the winter months when you feel the worst? Because everyone is impacted by the change of the seasons, you also need to examine the level of severity. Are the changes you note mild, marked, severe, or disabling? (Adapted from the Seasonal Pattern Assessment Questionnaire by Rosenthal, Bradt, & Wehr). If your pattern is fairly consistent and you are significantly affected, you might benefit from treatment.



  • Do anything you can to increase your exposure to light during the winter months. Increase the light level in your home. Take a walk at midday. Take a winter vacation to a southern latitude.
  • Establish a regular exercise routine.
  • Reduce your stress level.
  • Light Therapy (Phototherapy)

    Much research has been conducted in recent years examining the efficacy of light therapy for SAD. Although still being explored, current thought is that exposure to bright light on a daily basis can help ameliorate the symptoms of SAD. The light must be high intensity (generally between 2500 and 10,000 lux). For comparison, the average office is lighted to between 500 to 700 lux whereas the amount of light coming off a summer sky is over 100,000 lux. Full spectrum lighting is not necessary. Generally, a person needs to sit close to the light, making sure the eyes are not shaded, for between 20 and 40 minutes a day, preferably first thing in the morning. Although available for purchase without a prescription, a consultation with a mental health professional is recommended before trying light therapy.

    Professional Help

    There are currently a variety of highly effective interventions available for the treatment of SAD. Evaluation and consultation with a mental health professional (psychologist, psychiatrist, counselor, or social worker) will help you determine the best treatment for you. Treatment may include counseling/psychotherapy, light treatment and/or medication.

    Recommended Books to Read

    • Winter Blues: Seasonal Affective Disorder. What It Is and How to Overcome It. Norman E. Rosenthal, New York: Guilford, 1998.

    Need Additional Help?

    Washington State University College of Veterinary Medicine Counseling and Wellness Services offer free individual counseling for these and related issues for veterinary students (WSU Veterinary Students ONLY). For more information or to schedule an appointment call or e-mail:

    Anne LaFrance, MA, Licensed Mental Health Counselor
    (509) 335-4607
    135A McCoy Hall

    NOTE:  The information contained in these self help documents is not to be used as a substitute for professional care.  Neither the authors, Washington State University nor the College of Veterinary Medicine assume liability for injury incurred by following the information presented in these self-help documents
    Last Edited: May 12, 2014 9:25 AM   

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