The Sun & Seasonal Affective Disorder

 from the NeuroNetwork for Emerging Therapies Mini Symposium Series: Here Comes the Sun

A Subtype of Depression

  • Low mood
  • Loss of interest or pleasure
  • Feelings of guilt, worthlessness, or hopelessness
  • Low energy
  • Mood symptoms reliably occur during specific seasons (typically fall/winter), with remission in between
  • Increased need for sleep
  • Carbohydrate cravings (increased appetite and weight gain)

Impacts up to 2.4% of the general population, but up to 20% of those with major depressive disorder

Causes of SAD

Not well-established, but may include:

  • Disruption in light-signaling pathways—reduced serotonin activity with shorter day length
  • Sleep-circadian rhythm dysregulation—delay in body clock relative to sleep
  • Genetics—family history is a risk factor

Treatment Options

  • Light Therapy—also an effective treatment for non-seasonal depression
  • Cognitive—behavioral therapy (CBT)
  • Medications (SSRIs, specifically fluoxetine and sertraline)
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Light Therapy

Light as an Antidepressant

  • Increases mood-positive neurotransmitters
  • Resynchronizes internal clock with the external clock
  • Improves sleep
  • Increases alertness

Light Therapy Devices

photo of a light therapy box
Photo of light therapy glasses
photo of the sun

How to Use Light Therapy

  • Wake up at the same time daily, so you can use light therapy at the same time daily (when you wake up).
  • Aim for at least 30 minutes, but can adjust to 15-60 minutes
  • Avoid using it later in the day, especially evening.