Neon Genesis Evangelion (1995)

This may be a hard recommendation to make for many people despite its ubiquity. It's a bit like the Twin Peaks of anime, at times almost hostile to outsiders and has a cult-like following but if you give it the time and patience you will be rewarded. It can be disjointed, slow, uneven, and downright confusing. But the most important thing is the emotionality especially for anyone who's suffered severe loneliness and/or depression; It serves as a deep reflection of the creator's own mental health. I can't say that will assuage the feeling of grief or trauma; Often times the show will trigger quite heavy feelings. But it does have a lot to say about self doubt, self care, abandonment, and every co-morbid mental health issue you can think of. The series is already great stand-alone but to certain people the ending can feel very abrupt in which case you might want to watch the movie (End of Evangelion) that takes place concurrently during the last two episodes but be warned it could leave you even more confused.