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Seasonal Affective Disorder might be a myth: http://blogs.discovermagazine.com/crux/2016/02/09/seasonal-affective-disorder-sad/ http://blogs.discovermagazine.co

• derefr 11y ago
  The crux of that article's argument is that they fail to find any correlation between latitude/light-exposure and depression. But Seasonal Affective Disorder—although frequently defined in terms of feeling "depressed"—is not defined as a kind of clinical depression: its symptoms do not heavily overlap with the clinical-depression symptoms they were looking for. I Am Not A Neurologist, but my understanding from reading various journal articles is that the photosensitive ganglion cells in the retina (the ones that detect mostly blue light and are known to calibrate circadian rhythm) do what they do by stimulating dopamine release when their activation potential is reached. Presuming that this production of dopamine due to direct-light stimulation is relied upon by developmental processes, then this can explain nearsightedness; without direct light, children produce too little dopamine, and so their eye muscles are left slightly more "slack", allowing the eye to grow in a deformed shape. Presuming also that this conditional production of dopamine continues to be relied upon to hold to some average level even after development, then "SAD" would be, effectively, an environmentally-induced Attention-Deficit Disorder, and not any kind of "depression" at all. (Note that people with undiagnosed ADHD almost always first assume that what they have is depression. "My life is crappy and it makes me want to disengage from it" is very easy to confuse with "I lack the motivation to improve things, so I let them turn to crap instead.") I would bet that if they looked for a correlation between those—light-exposure and ADHD symptoms—they'd find something much more interesting.