THE UNIVERSITY OF CHICAGO Student Counseling AND RESOURCE SERVICE

Seasonal Affective Disorder (SAD)

D. Murstein, M.D.
January 30, 2002

SAD is a type of seasonal depression, usually occurring in the winter, which affects millions of people a year between September and April with the peak occurring in the winter months of December, January, and February. True SAD is a seriously disabling illness, preventing people from functioning normally. In addition, millions of others suffer from a milder version called "subsyndromal SAD" or "winter blues," less disabling but still impairing and uncomfortable. There is a more rare form of summer SAD in which symptoms occur in the summer and remit in the winter.

Contents

• Diagnosis
  • Scales for Assessing SAD
  • Keys to the Development of SAD
  • Differential Diagnosis
• Etiology
• Prevalence
• Treatment
  • Parameters for Light Therapy
  • Side Effects of Light Therapy
  • Medications
  • Choosing between Light Therapy and Medications
• References
  • Web Sites
  • Books for Patients
• Addendum

Diagnosis

• Recurrent major depressive episodes that start around the same time each year (e.g. September-October) and remit around the same time each year (e.g. March-April).

• Full remission of symptoms during the unaffected periods of the year (e.g. May-August), otherwise the diagnosis of major depression may be more accurate.

• Over the lifetime course of the illness there are relatively more seasonal depressive episodes than non-seasonal episodes.

• Seasonal depressive episodes occur in at least 2 consecutive years.

• Core symptoms:

  • Increased sleep (70-90% of SAD patients)
  • Increased appetite (70-80%)
  • Unacceptable weight gain (70-90%)
  • Carbohydrate craving (80-90%)

• Other symptoms:

  • Fatigue/inability to carry out normal routine
  • Feelings of misery, guilt, low self-esteem, despair, apathy
  • Irritability
  • Avoidance of social contacts ("hibernation" syndrome)
  • Increased susceptibility to stress
  • Decreased interest in physical contact and sex
  • In some: mood swings and periods of hypomania in spring & autumn

• Symptoms in children:

  • Feeling tired and washed out
  • Feeling cranky and irritable
  • Temper tantrums in the winter months
  • Slipping grades

Scales for Assessing SAD (in addition to the clinical interview)

• SPAQ = Seasonal Pattern Assessment Questionnaire -- simple, brief, and useful

• SIGH-SAD = Structured Clinical Interview Guide for the Ham-D, SAD version.

• Beck Depression Inventory (version II)

Please also see the addendum.

Keys to the Development of SAD

• Inherent vulnerability (genetics)

• Light deprivation

• Stress

Differential Diagnosis

Medical conditions to rule out when suspecting SAD:

• Hypothyroidism (low thyroid -- correctable with medication)

• Anemia (various causes -- usually can be treated with iron and/or B12 vits.)

• Hypoglycemia (low blood sugar) -- dietary changes to control

• Chronic viral illness (e.g. Epstein-Barr)/Chronic Fatigue Syndrome

Although these do not have a seasonal pattern, with the exception of more viral infections in winter, it is wise to check for them in anyone presenting with the symptoms of SAD.

Etiology

Studies have shown variable mechanisms, not always consistent from study to study, including:

• Seasonal variations in serotonin, which is higher in the summer and fall and lower in the winter and spring. SSRIs may help to combat SAD. Some studies show abnormal serotonin metabolism at the level of the post-synaptic serotonin receptor.

• Phase delayed circadian rhythms -- reset by bright light therapy

• Hypothalamic dysregulation-changes due to lack of stimulation via the pineal gland

• Mechanical impairments (cataracts, wearing of the Chador, reversed shift work)

• However, exact mechanism not known

Prevalence

• Varies with latitude, initially overestimated due to self-report nature of SPAQ. With more rigorous diagnosis, approximately 2-4% of population of Canada and 1-2% of US population, depending on geography. On average, an additional 10% suffer from subsyndromal SAD ("winter blues").

• Women 2-4 times as likely as men to have SAD, depending on study.

• Prevalence unknown, up to 5% in one study of children in MN had a high degree of mood changes with seasons. Fewer meet criteria for full-blown depression.

Treatment

• 1980 -- circadian study shows that >2000 lux light intensity needed to suppress nocturnal melatonin.

• 1984 -- first controlled study of SAD therapy with bright light: 2,500 to 10,000 lux. 10,000 lux is approximately the amount of light outdoors 1/2 hour after dawn.

• Currently -- over 60 controlled studies (most placebo controls with "sham" light of lesser intensity) show an average response rate of 65-90% for bright light therapy.

• Some studies show equal efficacy for "dawn simulators."

Parameters for Light Therapy

• Intensity -- 2,500 (1-2 hours/day) to 10,000 (30 minutes/day) lux, Higher intensity results in less time needed for treatment efficacy.

• Wavelength -- not as important as intensity, but most favor "broad spectrum" wavelengths closer to natural light than limited wavelength bands.

• Duration of exposure -- 30 minutes to several hours, depending on intensity and needs of the individuals. Less time for children.

• Time course -- response usually occurs in 2-4 days with more noticeable improvement within a week. Atypical symptoms of depression (increased appetite, increased sleep, weight gain, carbohydrate cravings) respond better than classical melancholic symptoms.

• Time of day -- lights may be used at any time of day, although several studies find AMs to be more effective and late PM use to cause activation and possible insomnia.

Side Effects of Light Therapy

This percentagereport this symptom 19-27eye strain or visual disturbances 13-21headache 6-13feeling agitated or "wired" 7nausea 7sweating 6-7sedation

Side effects are usually mild and diminish with time or reduction of exposure. Rarely, but importantly, hypomania and mania can be induced with light therapy. Five year light therapy use studies have not shown any eye or retina damage, and routine ophthalmologic monitoring is not considered necessary in the absence of risk factors for retinal damage such as old age, diabetes, cataract surgery and lens removal, retinal detachments, glaucoma, photosensitizing medications (lithium, St. John's Wort, melatonin, phenothiazines, and some others).

 

Medications

The best evidence for the treatment of SAD with medications is for the SSRIs. Large studies have shown fluoxetine (Prozac) and sertraline (Zoloft) to be effective, and there is no reason to think that the other medications in this family would not be equally effective. Non-SSRI antidepressants have not had adequate sample sizes and study designs to prove efficacy. Dosing is comparable to dosing for any other depressive disorder.

 

Choosing between Light Therapy and Medications

The severity of the depression, motivation and time for light treatment, associated medical conditions, prior experience with medications and light therapy, cost and other factors influence the decision.

 

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References

1. Eastman CI, Young MA, Fogg LF, Liu L, Meaden PM: Bright light treatment of winter depression: A placebo-controlled trial, Arch Gen Psychiatry 1998; 55: 883-9.

2. Kogan AO, Guilford PM: Side effects of short-term 10,000-lux light therapy, Am J Psychiatry 1998; 155: 293-294.

3. Lam RW (ed): Seasonal Affective Disorder and Beyond: Light Treatment for SAD and Non-SAD Conditions, Washington DC: American Psychiatric Press, 1998.

4. Lam RW, Levitt AJ (eds): Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder, Canadian J of Diagnosis.

5. Moscovitch A, Blashko C, Wiseman R, et al: "A double-blind, placebo-controlled study of sertraline in patients with seasonal affective disorder," New Research Abstracts, 151st Meeting of the Am. Psychiatric Assoc., 1995.

6. Rosenthal NE, Sack DA, Gillin JC, Lewy AJ, Goodwin FK, Davenport Y, Mueller PS, Newsome DA, Wehr TA: Seasonal affective disorder: A description of the syndrome and preliminary findings with light therapy, Arch Gen Psychiatry 1984; 41: 72-80.

 

Web Sites

• Center for Environmental Therapeutics

• Clinical Chronobiology, Columbia University

• Seasonal Affective Disorder Information, University of British Columbia

• Seasonal Light/SAD Homepage

 

Books for Patients

(no picture, sorry)

Don't be SAD: Your Guide to Conquering Seasonal Affective Disorder, by Celeste A. Peters

Winter Blues : Seasonal Affective Disorder and How to Overcome It, by Norman E. Rosenthal, M.D.

 

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Addendum

Date: Thu, 21 Nov 2002 09:07:18 -0500

I have a few of suggestions for your Scales section.

The SPAQ is not readily available, and it is a somewhat outdated instrument with many extraneous questions and without an interpretation guide. The Personal Inventory for Depression and SAD -- which incorporates the key SPAQ items, an item for determination of a major depressive episode in the past year and an item to assess reverse neurovegetative symptoms that characterize SAD -- is available as a free download here.

The SIGH-SAD, in both self-rating and interview formats, is available here. This instrument is of most utility to clinicians and is not designed for self-evaluation.

A newer instrument, the Automated Morningness-Eveningness Questionnaire (AutoMEQ), has been designed for on-line use in specifying the optimum light treatment time of day. Its score correlates highly with circadian rhythm phase as measured by the onset of pineal melatonin secretion. It is available free here in two formats: (a) for volunteer participation in an IRB-approved epidemiology research project that requires entry of personal information (but no personal identification); and (b) for personal use only.

These instruments were devised at New York Psychiatric Institute in collaboration with Drs. Janet Williams and Tom White. The Center for Environmental Therapeutics (CET) is the designated distributor. CET is a 501(c)(3) nonprofit research and education agency for which Williams and I serve as scientific advisers and for which I am currently president.

I hope this information is useful to your students and colleagues at University of Chicago and others who visit your web site.

Michael Terman PhD
Professor, Psychiatry
Columbia University

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Revised: November 21, 2002
Developed by: Robert Hsiung, MD, dr-bob@uchicago.edu
URL: http://counseling.uchicago.edu/vpc/uchicago/sads.html
All contents copyright 2002 University of Chicago. All rights reserved.