Also, something that’s a surprisingly major factor: Adults need 8 hours of sleep every night. Teenagers need 10. Those two hours make one hell of a difference.
Like, my high school routine was waking up at 5 AM to catch the bus at 6 - I lived in a small town with no high school, so my bus route picked us up then had to spend awhile collecting all the farm kids before bringing us to school, so I’d get there at about 8. School would be done at about 3:15, and I’d be back on the bus for 3:30, to get home at about 5:30 PM. Let’s take an hour or so to eat dinner, shower, and just generally take care of any chores that need doing (laundry, cleaning litterboxes, ect), and then I could start on homework at 6:30. Three hours of that brings us to 9:30 PM, but uh oh! We’ve got a problem here! Let’s say I finish my homework exactly at 9:30 go straight to bed, and fall asleep immediately. That means I wake up at 5 AM the next day with only six and a half hours of sleep. Three and a half less than what I need.
But that’s not too bad, that’s survivable, right? And I’d always fall aslepe on the bus, so let’s be generous and call the naps an extra hour and a half of sleep, pushing us up to eight hours. Except I’ve got ADHD, and one of the effects of that is extreme difficulty falling asleep - unless I’m passing out from exhaustion, it takes me at least an hour to fall asleep, dropping us back down to 7 hours. And nowhere in here is there room for personal time! I’m not a social animal; I need time alone with my own head, or I start to really lose my shit. Let’s call it at least three hours of that every day, which was the bare fucking minimum needed to convince myself that suicide was probably a bad idea, and jesus fucking christ we’re down to four hours of sleep, and a solid hour of that is just a fucking nap on the bus.
That was my schedule. Every. Single. Day. Four hours of sleep, if I was lucky and my insomnia didn’t act up, and I had nothing else going on. On a really good day I might get five or six hours. That’s difficult for an adult. For a teenager, it’s torture. But it’s okay! Yeah, I had a massive sleep deficit, but that’s what weekends are for! Fourteen hours of sleep may be a bit extreme, but dear fucking lord did I ever need it. But oh wait, everyone knows teenagers are super lazy and that definitely included me. Just look at how I’d sleep past noon if left to my own devices! Thank god I had my loving and understanding parents to forcibly drag me out of bed at a reasonable hour in the morning on weekends to ‘save’ my sleep schedule. After all, I had a really hard time getting up in the mornings, and I’d sleep through my alarms sometimes, so that obviously meant I needed to sleep less on my days off, to make sure I didn’t get too used to it. Oh, and remember, not only did I have to go through all my classes with like 4 hours of sleep, I also had to do it with an untreated learning disability and no accommodations. And I was going hungry more often than not on top of it all, because the mountain of stress and exhaustion I was under meant that I rarely had the energy or executive function to make myself breakfast, and packing a lunch for myself hasn’t been possible since junior high. I’m pretty sure four hours of sleep and one meal a day is all a growing teenager needs to function; I mean I didn’t fucking die, so I was probably fine. I only dissociated hard enough to accidentally wander out into traffic a few times, it wasn’t so bad.
…and that is why I burned out so hard i pretty much dropped out of high school, finally finished the last few courses I needed to graduate in night school when by the time was 19, and now at 21 I’m still struggling to explain to my parents that I’ll start attending university once the idea of returning to school doesn’t make me genuinely want to fucking die. Which will probably be never.