As daylight disappears and temperatures drop in the fall, many people notice a shift in their mood, energy, and sleep. For five percent of Americans, there is a risk for Seasonal Affective Disorder (SAD), a form of depression triggered by seasonal changes.

According to the National Institute of Mental Health (NIMH), SAD is a recurrent depressive disorder with symptoms that typically last 4 to 5 months a year, usually beginning in late fall or early winter and resolving in the spring or summer (NIMH).

Signs and Symptoms: How to Diagnose SAD

According to American Psychiatric Association, the core symptoms of SAD overlap with major depression and include:

• Persistent sad, anxious, or “empty” mood

• Loss of interest or pleasure in activities once enjoyed

• Fatigue or decreased energy

• Feelings of hopelessness or worthlessness

• Difficulty concentrating or making decisions

• Changes in appetite or weight

• Sleep disturbances

• Physical symptoms such as headaches

• Thoughts of death or suicide

The symptoms might last up to five months, according to the National Institute of Mental Health.

Who’s at Risk?

Not everyone is equally affected by SAD. According to the Cleveland Clinic, it’s more common in:

• Adults between 18 and 30

• Women

• People with a personal or family history of depression or bipolar disorder

• People living far from the equator, where daylight hours are shorter in winter

• Those living in cloudy regions with limited sunlight exposure

Treatment Options That Work

• Cognitive behavioral therapy (CBT).

• Antidepressants, such as SSRIs or bupropion, approved by the Federal Drug Administration for treating SAD.

• Lifestyle changes, including regular exercise, maximum time outdoors, plenty of light indoors, and vitamin D supplements.

• Phototherapy.

Light Therapy: What Lamp To Choose 

Phototherapy uses special lamps emitting 10,000 lux of bright white light. The lamp should be used for 15–30 minutes each morning. 

• Place the lamp about 20 inches from your face, without looking directly at it.

• Many users feel better within several days, though full effects can take two weeks.

• Light therapy should continue daily throughout winter to prevent relapse.

What Else You Can Try

Lithium has shown promising results as a treatment for depression, but is available on prescription only. If you would like to try lithium as a supplement at a low dose without a prescription or serious side effects, read more about lithium ascorbate.