Seasonal Affective Disorder (SAD)

Primer

Seasonal Affective Disorder (SAD) (also known as Major Depressive Disorder with seasonal pattern in the DSM-5) is a subtype of depression related to mood changes that are linked to seasonal changes. The diagnostic specifier “with seasonal pattern” can be describe a seasonal pattern of symptoms in both major depressive disorder and bipolar disorder.

Prevalence
  • The prevalence of winter-type seasonal pattern varies with latitude (increases with higher latitudes), age, and sex.[1]
Risk Factors
  • Age is a strong predictor of seasonal depression, with younger persons at higher risk for winter depressive episodes.[2]

DSM-5 Diagnostic Criteria

This specifier applies to the lifetime pattern of mood episodes. The essential feature is a regular seasonal pattern of at least 1 type of episode (i.e. - mania, hypomania, or depression). The other types of episodes may not follow this pattern. For example, an individual may have seasonal manias, but his or her depressions do not regularly occur at a specific time of year.

Criterion A

There has been a regular temporal relationship between the onset of manic, hypomanic, or major depressive episodes and a particular time of the year (e.g. - in the fall or winter) in bipolar I or bipolar II disorder. Do not include cases in which there is an obvious effect of seasonally related psychosocial stressors (e.g. - regularly being unemployed every winter).

Criterion B

Full remissions (or a change from major depression to mania or hypomania or vice versa) also occur at a characteristic time of the year (e.g. - depression disappears in the spring)

Criterion C

In the last 2 years, the individual’s manic, hypomanic, or major depressive episodes have demonstrated a temporal seasonal relationship, as defined above, and no non-seasonal episodes of that polarity have occurred during that 2-year period.

Criterion D

Seasonal manias, hypomanias, or depressions (as described above) substantially outnumber any nonseasonal manias, hypomanias, or depressions that may have occurred over the individual’s lifetime.

Signs and Symptoms

  • Major depressive episodes that occur in a seasonal pattern are often characterized by prominent energy, hypersomnia, overeating, weight gain, and a craving for carbohydrates.
  • This specifier can be applied to the pattern of major depressive episodes in bipolar I disorder, bipolar II disorder, or major depressive disorder, recurrent.
  • The essential feature is the onset and remission of major depressive episodes at characteristic times of the year.
    • Typically the episodes begin in fall or winter and remit in the spring. Less commonly, there may be recurrent summer depressive episodes.
    • This pattern of onset and remission of episodes must have occurred during at least a 2-year period, without any nonseasonal episodes occurring during this period.
    • Finally, the seasonal depressive episodes must significantly outnumber any nonseasonal depressive episodes over the individual's lifetime. The seasonal specifier also does not apply to those situations in which the pattern is better explained by seasonally linked psychosocial stressors (e.g. - seasonal unemployment or school schedule).

Treatment

Light Therapy

  • Light therapy is indicated as a first-line treatment of depression with seasonal affective subtype
  • The standard intensity of light needed is usually 10,000 lux (light intensity) for 30 minutes per day in the early morning for a period of 6 weeks.[3]

Pharmacotherapy

  • Bupropion has been shown to be effective in the prevention of SAD by starting treatment prior to the winter season.[4]

References

1) American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.
2) American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA.
3) Ravindran, A. V., Balneaves, L. G., Faulkner, G., Ortiz, A., McIntosh, D., Morehouse, R. L., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 5. Complementary and alternative medicine treatments. The Canadian Journal of Psychiatry, 61(9), 576-587.
4) Modell, J. G., Rosenthal, N. E., Harriett, A. E., Krishen, A., Asgharian, A., Foster, V. J., ... & Wightman, D. S. (2005). Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL. Biological psychiatry, 58(8), 658-667.