I recommend using f.lux and Twilight for PC and Android respectively, if you use technology at night.
In regards to depression, the cure is simple. Just be positive. I know it's not a definitive answer, but it's really the only way to not be depressed. If you don't want to drown, then you must swim. That desire alone should be enough to wake someone up from depression, but it's not as simple as that.
There was a friend of mine who suffered from depression. He told me about his thought patterns, and said he often had suicidal thoughts. When asked "what reason do you have to be depressed?", he told me about the triggers that caused his depression. So I asked, "why is it still affecting you, even though it happened in the past?". And he said "I don't know". So I told him that his mind was reliving past memories and thoughts, just stewing in those old emotions. Once you enter that mindset, it's very difficult to get out. Especially when psychomotor retardation kicks in (basically, so depressed that you don't have the energy to get up in the morning).
A lot of people, like my friend, ask the question "what's the point in getting up in the morning?". To which, nothing and no one responds. And so they lie in bed for much longer than is necessary, for some people, all day. Add ease of technology, and it becomes extremely easy to get a quick dopamine fix. It is a self defeating mentality.
The only solution I can see is to give your life purpose. This can only happen within your mind. You can give your life purpose by setting a goal, turning to role models or just a desire to escape the torment that is depression. You can channel your negativity into positivity. One trick I implement when I'm feeling a bit down is to say to myself "why am I sad? What purpose does this serve? ABSOLUTELY NOTHING! GET UP AND DO SOMETHING!". And this works a treat. I get up, and read a poem that I have attached to my bedroom wall. It's what gives me inspiration. And I go out and do something. Literally anything. The feeling of being active and physically doing something gives me some sense of living.
In regards to seasonal affective disorder, a lot of people don't like rain or snow. They see it as a hindrance, and consequently, feel bitter when it comes. When it is raining or snowing for weeks at at time, it's easy to see why seasonal affective disorder is a thing. There is a certain type of person that I've noticed. These people, NEVER get bogged down by the weather or seasons or anything. These people love ALL types of weather. When it rains, they walk in the rain with no umbrella. They embrace it. And it turns out, it's not just weather that they love. It's everything.
When you feel love, nothing can stop you.To those who feel unloved, all you need to do is reach out. I guarantee there will be a hand for you, all you gotta do is reach.
I come from a biomedical science background, and I absolutely detest big pharma. Remember,
change comes from within.
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."