I think the main issue is that most mental illnesses are vaguely defined clusters of problems - if you represented a diagnosis as a vector where each index corresponded to severity of a particular symptom, the diagnosis space would not properly aligned with the actual disease basis. This introduces ambiguity - a single disease tends to fall into multiple clusters when your representational domain is misaligned with the actual data axes.
The solution is ML. Neural networks with appropriate architectures effectively perform a change of basis, mapping the data basis to an output coordinate system. When properly trained they can automagically orient their internal representation with the true data bases.
For most people, even with shitty parents, your still parents sacrificed for you and raised you. A loyal human would not abandon them without great reason. Cutting contact should be a last resort, even if that means slightly worse mental health for yourself. Yes, you do owe them some minimum of respect and kindness if they showed you the same in raising you. That leads to better outcomes for society.