I am, like lara, absolutely positive that the emotional and psychological effects of summer are far worse than the biological, but this is just my opinion, the debate on this goes on. I do believe though that the biological explanation is also viable but not in a so large degree that it is can cause all of the summer stress.
As I said in the post, I just want to share this and it is not a blunt fact.
I think that the two factors together, leaving in the middle which factor adds how much, contributes to the summer stress.
What a hell it must be living somewhere where it is always summer lol.