It is a guessing game because of the nature of the complaints. When your back hurts it is not normal, that is easy to decide. But you have no motivation towards life? This complicates things by orders of magnitude. Maybe you are naturally born that way, maybe you had certain traumas, maybe you had no particular trauma but your upbringing lead you that way slowly, maybe you had shitty friends or family... List goes on. It is even harder for deciding what is normal and what is not. How much sadness or joy should counted as pathological and under what conditions?

Psychiatry has the most subjective organ of interest of all fields in medicine.

There has been a lot of criticism of the DSM over the years, most of it justified. Labels like "borderline personality disorder" are almost so vague as to be unhelpful.

At the same time, nobody has come up with anything better. There is so much nuance that simple labels can never capture what is really going on.

If you wanted to really accurately capture someone's personality you would need dozens of scales, 0-100, like a sadistic variant of a table-top RPG. Many of these sliders would have similar competing effects, and any test you gave would never be able to single out a single value. Then, on top of that, people actively hide and deceive the real answers to questions, and the answers might change significantly from day to day.

The key takeaway here is that you can't self diagnose or treat using labels from the DSM or (even worse) western pop psy. Practicing self awareness, finding someone you trust enough to talk honestly with, and if feasible a really good psychologist (because there are plenty of mediocre ones out there, too) is more important.