Seasonal Affective Disorder

What Is Seasonal Affective Disorder (SAD)?

Seasonal affective disorder, or SAD, is a type of depression that is linked to the changing seasons. It occurs most commonly in the late fall and winter months, but also occasionally during spring and early summer. About five percent of American adults experience SAD, with women more susceptible than men. Hormonal imbalances likely play a role in the onset of this condition. Several treatment options are available, including therapy and medication.

SAD should be taken seriously; like any depression, it can sap you of your energy and make daily living difficult or unpleasant. If you or a loved one is battling the winter or summertime blues, the health-care experts at Baptist Health may be able to help.

What Are the Symptoms of Seasonal Affective Disorder (SAD)?

SAD is characterized by the appearance of depression-like symptoms in conjunction with seasonal change:

  • Feelings of melancholy or remorse
  • Sluggishness and loss of energy
  • Lack of interest in things that normally appeal to you
  • Trouble sleeping
  • Feelings of anxiety or agitation
  • Fluctuations in appetite and weight
  • Poor concentration
  • In more extreme cases, a preoccupation with death and suicide

There are some distinctions between the winter and summer versions of SAD. Wintertime SAD is marked by oversleeping, overeating, and weight gain, whereas summertime symptoms more often include insomnia, weight loss, and high levels of anxiety.

What Are the Causes of Seasonal Affective Disorder (SAD)?

Though tied to times of the year, SAD’s medical causes are not well understood. Researchers view hormonal fluctuations triggered by variations in daytime light as a primary culprit. Changes in brain chemistry can lead to changes in emotional states, such as:

  • Serotonin levels: Serotonin is a neurotransmitter connected with feelings of cheerfulness and well-being in humans. It is photosensitive, which means that reductions in sunlight can lead to reductions in serotonin.
  • Melatonin levels: Melatonin is a hormone with a variety of physiological functions. The body’s production of melatonin is inversely proportional to the amount of sunlight, meaning that as sunlight decreases, melatonin increases. Elevated levels of melatonin can lead to lethargy and sleepiness.
  • Circadian rhythm: The circadian rhythm is the body’s “internal clock” for regulating the sleep-wake cycle. Seasonal change can disrupt the normal circadian pattern, affecting sleep and mood.

There are several risk factors that increase the likelihood of experiencing SAD, including a family history of depression or being diagnosed with a bipolar disorder. SAD also appears stronger in people living closer to the Earth’s poles than the equator, presumably because of greater variation in the length of daylight hours.

How Is Seasonal Affective Disorder (SAD) Diagnosed?

Because SAD’s symptoms are common to other forms of depression, your physician or mental-health provider may find diagnosing this condition to be tricky. Here are some steps he or she is likely to take:

  • Physical exam: An exam is important as a means of ruling out an underlying physical or medical cause of your depression.
  • Family medical history: Because of the prevalence of depression and other mental-health conditions in some families, your physician will want to know your medical history.
  • Lab work: Blood tests and other forms of lab work can help pinpoint certain endocrinological conditions that might be driving hormone imbalances.
  • Psychological evaluation: You might be asked to fill out a questionnaire with the purpose of documenting medical and behavioral evidence for depression. Your physician can use this information, in conjunction with the criteria published by the American Psychiatric Association in the Diagnostic and Statistical Manual of Mental Disorders, or DSM, to make his or her diagnosis.

How Is Seasonal Affective Disorder (SAD) Treated?

The primary means of treating seasonal affective disorder are prescription medications and therapy.


Persons suffering from SAD are sometimes treated with antidepressant medications. If your SAD is recurring, your physician might suggest that you begin taking the medication prior to the seasonal change that triggers your condition.

Light therapy

Another common method of treating SAD is light or phototherapy. This involves sitting by a specially designed light box when first getting out of bed to start your day. The light stimulates the production of hormones that regulate mood and emotion. Phototherapy appears effective in dealing with SAD but is not recommended for people with a bipolar disorder, as it can generate manic episodes.


Psychotherapy – also called talk therapy – is used to address underlying personal issues that can result in depression. You’ll learn how to identify and correct negative habits or behaviors, as well as healthy ways of coping with SAD.

There are also steps you can take on your own to prevent the onset of seasonal depression. Exercising, eating healthy, spending time outdoors, and staying involved with family and friends can all work to counteract the changes you may feel when the seasons change.

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