What Causes SAD (Seasonal Affective Disorder)?

By K Health
Medically reviewed
November 19, 2019

Though the exact cause of Seasonal Affective Disorder (SAD), a type of depression, has not been pinpointed yet, the following are some key factors that may influence your susceptibility to SAD:

  • Melatonin levels – the shift in seasons may throw your body’s melatonin off balance, which may cause irritability and a change in sleeping patterns
  • Serotonin levels – a study found that people diagnosed with S.A.D. have lower levels of available serotonin, a neurotransmitter that may influence mood
  • Vitamin D – being exposed to less sunlight may lower your production of vitamin D, which also influences serotonin. Low levels of vitamin D have also been linked to depression.
  • Circadian rhythm – decreased levels of sunlight during the colder seasons may interrupt your body’s internal clock and disrupt sleep patterns.

As you may have noticed, most of these elements are linked to a change in your exposure to sunlight. One common treatment for S.A.D. is light therapy, which mimics sunlight and allows your body to naturally amend your mood. Other common treatments for S.A.D. include (either alone or in conjunction) medication, psychotherapy, and vitamin D.

Suspect you have Seasonal Affective Disorder? On the K Health app, you can chat with an expert doctor to get treatment.

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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.