Then you have to admit the alternate explanation that people do not identify as having PTSD when they do, either because they don't know the signs or because it would be useless or embarrassing to do so.
Self-reporting is fraught when it comes to psychiatric disorders for a lot of reasons.
DST is (1) but synchronized. People could change their schedules to negate DST, and I'm sure some do.
Anyway, I don't want touch-grass time during my useless lunch hour, I want usable daylight hours after work during which to do outdoor things in the warmth of the sun. Where I am, people mostly seem to want year round DST (but of course it wouldn't be DST anymore, it would just be "the time").
Different places can and will do what suits their needs.
This is navel gazing along the lines of cocktail-fueled debates over a tree falling in a forest. Does light still have a color if no one is around to see it?
Fundamentally these words have lots of reasonable wiggle room to expand or narrow their definitions. Still, lots of technical domains would like to be explicit about what is meant, especially when reusing common words, which is why man invented the glossary.
Unfortunately this hasn't stopped endless argumentation over whether a tomato is a fruit or a vegetable. For whatever reason, it's often presumed that the definition of fruit used in botany has "won", even though botany has nothing to tell us about what a vegetable is or how to distinguish one from a fruit.
On the one hand you have light waves that hit some receptors in the eye. These receptors (various kinds) sensitive to frequencies according to a function. This creates a specific signal that is analyzed by the brain which assigns a "color" to that signal.
Everyone's, to some extent, functions are different. There is a general trend so most people agree on "colors". When you are colorblind, the functions differ drastically (or are just flat).
This is why "color" is a biological concept (same as, say, "pain") to which we are desperately trying to attach three or four numbers (or, worse, a wavelength)
