I have always found personality disorders (PD) fascinating so I appreciate this post. I think understanding a personality disorder can especially be empowering to those who have been raised by someone with a PD . There are many books out there for children of a borderline parent who often have a chaotic childhood. Nonetheless, there are a few corrections I want to make from your post.
One does not need to be a psychiatrist to diagnose someone with a personality disorder. A psychologist, clinical therapist, or clinical social worker can also make this diagnosis (at least in the USA - not sure about other countries). This is a good thing because psychotropic medications cannot fix a personality disorder, and psychiatrists typically do not provide therapy but instead focus on prescribing medication. Although medication can be helpful in managing symptoms related to the personality disorder (i.e. depression, anxiety, substance use), for some reason people with a personality disorder do not respond as well to medication as the client without a personality disorder. https://psychcentral.com/lib/treatment-for-antisocial-personality-disorder/
A personality disorder IS a mental illness, and a serious one at that. https://healthcommkey.org/how-are-personality-disorders-different-from-mental-illnesses/
According to the DSM 5, Passive Aggressive (although highly irritating) is not a personality disorder but instead a behavior that can be seen in some personality disorders.
I read somewhere that 1 out of every 20 people can be diagnosed with a personality disorder, but as a clinical therapist myself I find this number to be a bit high - unless they are also counting people with only features or traits instead of meeting the criteria for a full blown personality disorder. Most personality disorders are so hard to treat, but there are some therapeutic treatments that have proven to be helpful for certain disorders (i.e. DBT for Borderline Personality Disorder). However, from what I have heard (and through my own personal experience) talk therapy unfortunately can be counterproductive for the narcissistic sociopath.
Thanks for sharing, @zheimberg!