I see some problems with the said "5 of the 9 features" when employed for a different generations, 20 years apart. The concepts there are not fixed but change constantly and that may alter the final result as, for instance, something that would be considered a "sleep problem" today would not be considered a sleep problem back then.
Some examples, as I find it easier to explain what I'm talking about using those:
"depressive mood" - The nineties were the age of grunge music. Alice in Chains, Pearl Jam "sad phase", etc. Today's music seems less gloomy, overall. Hip hop, etc. - A depressed teenager would fit in back in the nineties, as that was the "standard", but would seem more depressed than their peers these days, even if his/her state of mind remained the same.
"change in appetite or weight" - People in America seem to be fatter today than back then. It is only natural that a depressed person with a predisposition to gaining weight would gain weight in a greater ratio back then, as their natural weight would tend to be lower in order to fit to society's standards of that time.
"sleep problems" - It seems to me that in the nineties, a depressed person would have less sleep problems, regardless of the severity of their depression, as at 3am there would be very few things to do but sleep. Now there is instagram, online gaming, Netflix, etc. so that even a less depressed person will show "sleep problems" to a higher degree as any tiny difficulty falling asleep will cause said person to be distracted with something else instead of "forcing himself/herself" to try to fall assleep.
"fatigue or loss of energy" - Again, the same person suffering at the same degree of depression might feel a different severity to their fatigue now as opposed to what they felt in the nineties simply because they walk much less now, that Uber leaves you in front of the building where you wanted to go instead of you having to find a parking spot nearby and walking the rest of the way to this place.
"excessive self-reproach or guilt" - Again, changes in society might alter the final result. Someone who felt no guilt whatsoever telling jokes about black people back in the nineties, for instance, might have changed their attitude as society changed during this time and now may feel guilty for not being involved with the BLM movement to the degree they feel they should.
Some examples from the top of my mind, so you have some food for thought.
This is a very important post to read concerning Bitcoin "billionaires", from one of the guys who helped code its software:
Not as rich as you think… - http://gavinandresen.ninja/not-as-many-as-you-think
It goes like this:
People assume that the people who worked on Bitcoin in the early years are fabulously wealthy.
That’s a bad assumption, for lots of reasons: