What could you tell someone who won't get help because they think their mental health problems are what defines them as a person?

Mental Health: Let the person know that you care. Encourage them to seek care because it can help their function and quality of life. But - remember, it is ultimately that person's decision. Call 911 for suicide or homicide risk.

Question: My first question would be, what do they get out of it? Why define one's self so narrowly?

Frustration, Anxiety: I understand your frustration. Many people communicating with such people at home, work or social situations feel that they are stubborn, rigid, righteous and inflexible. Do not argue, show your concern about their specific behaviors, ask them to put themselves in your shoes and tune in with your feelings. Write a letter expressing your concern. Offer to go with them to any Therapist they choose.