Table 1.

A comparison between seasonal Affective Disorder and Depression.

Seasonal Affective Disorder	Vs.	Depression
Reduced sunlight, circadian rhythm, latitude, vit D deficiency, melatonin overproduction, decreased serotonin levels, lower dopamine production	Etiology	Genetic factors; dietary factors; deficiency of neurotransmitters noradrenalin, serotonin, and dopamine; hypothyroidism; Cushing’s syndrome.
Similar	Symptoms	Similar
Possible weight gain	Weight gain	Possible weight gain/loss
More likely in the fall or winter	Timing	No specific time
Responding	Antidepressants	Responding
Responding	Light Therapy	Unclear. Needs more study.