Seasonal Affective Disorder – Causes, Symptoms, Diagnosis, Treatment and Ongoing care
- Seasonal affective disorder (SAD) is a heterogeneous mood disorder with depressive episodes usually in winter months with full remissions in the spring and summer.
- Noted to occur decades ago; not formally named until the 1980s
- Ranges from a milder form (winter blues) to a seriously disabling illness
- Must separate out patients with other mood disorders (such as major depressive disorder and bipolar affective disorder) whose symptoms persist during spring and summer months
- Affects up to 500,000 people every winter
- Up to 30% of patients visiting a primary care physician (PCP) during winter may report winter depressive symptoms.
- Predominant age: Occurs at any age; peaks in 20s and 30s
- Predominant sex: Female > Male (3:1)
- 1–9% of the general population
- 10–20% of patients identified as having mood symptoms will have a seasonal component.
- Most common during months of January and February: Patients frequently visiting PCP during winter months complaining of recurrent flu, chronic fatigue, and unexplained weight gain should be screened for SAD.
- Working in a building without windows or other environment without exposure to sunlight
- Some twin studies have suggested a genetic component, but further study is needed.
- Increased incidence of depression, attention deficit hyperactivity disorder and alcoholism in close relatives
- Consider use of light therapy at start of winter (if prior episodes begin in October), increasing time outside during daylight, or moving to a more southern location.
- Bupropion (Wellbutrin) is a Food and Drug Administration (FDA)–approved antidepressant for the prevention of SAD.
The major theories currently involve the interplay of phase-shifted circadian rhythms, genetic vulnerability, and serotonin dysregulation.
- Melatonin produced by the pineal gland at increased levels in the dark has been linked to depressive symptoms; light therapy on the retina acts to inhibit melatonin secretion.
- Serotonin dysregulation, because it is secreted less during winter months, must be present for light therapy to work, and treatment with selective serotonin reuptake inhibitors (SSRIs) appears to reverse SAD symptoms.
- Decreased levels of vitamin D, often occurring during low-light winter months, may be associated with depressive episodes in some individuals experiencing SAD symptoms.
Commonly Associated Conditions
Some individuals with SAD have a weakened immune system and may be more vulnerable to infections.
- Carefully document the presence or absence of prior manic episodes.
- Screen for the existence of any suicidal ideation and safety risk factors.
- Remission of symptoms during spring and summer
- Symptoms have occurred the past 2 years
- Seasonal episodes associated with winter months substantially outnumber any nonseasonal depressive episodes.
- Symptoms of depression meeting the criteria for major depressive disorder:
- Sleep disturbance—either too much or too little
- Interest (lack of)—in life and absence of pleasure from hobbies/activities
- Guilt—feelings of guilt or worthlessness
- Energy—fatigue or constantly feeling tired
- Concentration—difficulty with concentration and memory
- Appetite—changes in appetite and weight
- Psychomotor retardation—patients feeling slowed down with decreased activity
- Suicidal thoughts—patients reporting thoughts of suicide
- In SAD, hypersomnia, hyperphagia (craving for carbohydrates and sweets), and weight gain usually predominate. Despite sleeping more, patients report daytime sleepiness and fatigue. Cravings may lead to binge eating and weight gains >20 lb.
- Obtain collateral history if patient is unable to provide insight into the seasonal component.
Use exam to exclude other organic causes for symptoms. Focal neurologic deficits, signs of endocrine dysfunction, or stigmata of substance abuse should prompt further testing.
Diagnostic Tests & Interpretation
- Thyroid-stimulating hormone to rule out hypothyroidism
- Complete blood count to rule out anemia
- Rule out electrolyte and glucose dysregulation.
- 25-OH vitamin D level
- Pregnancy test for women of child-bearing potential
- Urine tox screen if substance abuse is a concern
Generally not useful unless focal neurologic finding or looking to exclude an organic cause
- Similar to that of major depression, meaning that organic causes of low energy and fatigue such as hypothyroidism, anemia, and mononucleosis (or other viral syndromes) need to be considered
- Other mood disorders without a seasonal component such as major depression, bipolar disorder, adjustment disorder, or dysthymia
- Symptoms should not be better accounted for by seasonal psychosocial stressors, which often accompany the winter holiday seasons.
- Substance abuse
There is a lack of evidence to determine whether light therapy or medication should be the 1st-line agent. Both are supported by the literature and in some studies have equal efficacy. Medications typically have more side effects. Adherence to both treatments remains a critical issue. The ultimate choice depends on the acuity of the patient and the comfort level of the prescribing clinician with each treatment modality (1)[B]:
- SSRIs such as sertraline (Zoloft), paroxetine (Paxil), fluoxetine (Prozac), citalopram (Celexa), and escitalopram (Lexapro) in their traditional antidepressant doses (2)[B]
- Bupropion (Wellbutrin) is the only antidepressant currently approved by the FDA for the prevention of SAD (3)[A].
Issues for Referral
- Patients with a history of ocular disease should be referred for an ophthalmologic exam before phototherapy and for serial monitoring.
- Patients who fail to respond or who develop manic symptoms or suicidal ideation once treatment is initiated should be considered for psychiatric referral.
Phototherapy using special light sources has been shown to be effective in 60–90% of patients, often providing relief with a few sessions (2,4)[A]:
- Variables that can regulate effect are:
- Light intensity: Although the minimum light source intensity is under investigation, 2,500 lux is suggested (domestic lights emit, on average, 200–500 lux). There is good evidence for 10,000 lux as the recommended source (2)[B].
- Treatment duration: Exposure time varies based on intensity of light source with daily sessions of 30 minutes to a few hours.
- Time of treatment: Most patients respond better by using the light therapy early in the morning.
- Color of light source: Emerging data suggest that lower-intensity light-emitting diodes in the blue spectrum may have equal efficacy to the traditional white light boxes with a decreased incidence of side effects, but these results are preliminary (5)[B].
- Light box is placed on table several feet away, and the light is allowed to shine onto the patient’s eyes (sunglasses should be avoided). Ensure that the light box has an ultraviolet filter.
- Most common side effects are eye strain and headache. Insomnia can result if the light box is used too late in the day. Light boxes also can precipitate mania in some patients.
- Dawn simulation machines gradually increase illumination while the patient sleeps, simulating sunrise while using a significantly less intense light source.
Complementary and Alternative Medicine
- Work to reduce stress levels through meditation, progressive relaxation exercises, and/or lifestyle modification.
- The potential role of vitamin D supplementation is under investigation. A small study found it to be more effective than phototherapy, but a much larger and more rigorous study recently found no benefit in elderly women for SAD symptoms. Doses used are typically 400–800 IU/d (6)[B].
If the patient develops suicidal ideation as part of his or her depression or mania after treatment is initiated
Regular monitoring by PCP or psychiatrist for response to treatment; patients may become manic when treated with SSRIs or light therapy.
Patients should be seen in the outpatient clinic weekly to biweekly when initiating light or pharmacotherapy to monitor treatment results, side effects, and any increased suicidal thoughts if using SSRIs.
No specific diet modification needed
- Increase time outdoors during daylight.
- Rearrange home or work environment to get more direct sunlight through windows.
Symptoms, if untreated, generally remit within 5 months with exposure to spring light, only to return in subsequent winters. If treated, patients usually respond within 3–6 weeks.
Development of suicidal ideation and mania are 2 outcomes the clinician needs to monitor.
1. Lam RW, Levitt AJ, Levitan RD, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J Psychiatry. 2006;163:805–12.
2. Lurie SJ, Gawinski B, Pierce D, et al. Seasonal affective disorder. Am Fam Physician. 2006;74:1521–4.
3. Modell JG, Rosenthal NE, Harriett AE, et al. Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL. Biol Psychiatry.2005;58:658–67.
4. Terman M, Terman JS. Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects. CNS Spectr. 2005;10:647–63; quiz 672.
5. Anderson JL, Glod CA, Dai J, et al. Lux vs. wavelength in light treatment of Seasonal Affective Disorder. Acta Psychiatr Scand. 2009.
6. Dumville JC, Miles JN, Porthouse J, et al. Can vitamin D supplementation prevent winter-time blues? A randomised trial among older women. J Nutr Health Aging. 2006;10:151–3.
A recent review article briefly outlining the diagnosis and current treatment of SAD is cited here for those interested in the subject.
Howland RH. Somatic therapies for seasonal affective disorder. J Psychosoc Nurs Ment Health Serv. 2009;47:17–20.
See Also (Topic, Algorithm, Electronic Media Element)
Bipolar I Disorder; Bipolar II Disorder; Depression
Algorithm: Depressive Episode, Major
296.99 Other specified episodic mood disorder
247803002 seasonal affective disorder (disorder)
- The difference between SAD and depression is that SAD is a subtype of major depressive disorder. Once someone has a diagnosed mood disorder such as depression or bipolar, one needs to ask whether the symptoms vary in a seasonal pattern to qualify for the diagnosis of SAD. Generally, these patients will report sleeping too much, eating too much (especially carbs and sweets), and gaining weight during winter months.
- As with all psychiatric diagnoses, ensure that the symptoms are not due to an organic process (e.g., anemia, hypothyroidism, mononucleosis) or better explained by substance abuse.
- There is a lack of good evidence to decide whether light therapy or SSRIs should be the 1st-line agent. Guidelines suggest that SSRIs should be used first if the patient is more acute or has contraindications to light therapy, or the clinician is not comfortable with light therapy.
- Light therapy boxes are available from numerous online suppliers, but they are not extensively regulated, and thus practitioners should take care to ensure that patients are using devices from reputable suppliers.
- If using SSRIs, there have been recent studies indicating that some patients may begin to experience increased suicidal thoughts on therapy, and thus these patients need to be monitored closely in your outpatient office every 1–2 weeks. Patients on light therapy also should be monitored closely initially in order to adjust treatment. Once stabilized, both groups of patients can be seen every 4–8 weeks during the winter months.
- All patients who demonstrate suicidal ideation or symptoms of mania should be referred for consideration of hospitalization.