I'm starting to think that there's an intrinsic challenge with young people being vulnerable to depression. They are thinking hard, trying to figure out what they're going to do, having all sorts of "firsts". Oppenheimer was apparently quite moody, more so when he was younger. There's an especially stark moment in American Prometheus where he unintelligbly screams, seemingly out of nowhere, and throws his luggage down a staircase, putting a woman on the stairs at mortal risk. His parents traveled to Europe to attend to him.
His daughter committed suicide. As did a lover of his.
I certainly have dark spells. When I was younger, I coped by withdrawing. Now, in my 40s, leading teams executing missions, I can't withdraw, it's very much "Hello darkness, my old friend".
Charles Bukowski has become a favorite author. Typing question stems into Google is far more therapeutic than browsing social media. Talking with a friend is more helpful than a therapist. Exercise, similarly. Talking with a friend while riding a bike is positively curative.
Life sucks, then you die. Stop and smell the roses. Shadenfreude isn't all bad. Etc.