Fantastic Beasts Headcanon
An Obscurus is a very extreme, physical representation of youth and teen depression.
In Fantastic Beasts, an Obscurus is created when a young, magical child attempts to repress their magical gifts. A powerful darkness is born, treating the child (or young adult) as a host, slowly feeding off of them if they don’t perform magic. Eventually, the host will die.
This seems like a very close synonym for young adults and children with depression at an early age, facing pressures much too soon and developing a growing fear of showing who they really are, for fear of being rejected. Slowly, this pain and anguish eats away at them, and in the worst of cases, could lead to them lashing out at others or themselves. It’s a creeping darkness that slowly chokes the life from what they could be, and they end up destroying themselves.