In my opinion, “personality disorders” are more easily understood as signaling problems.
All types of personality disorder involve dysfunctional signaling with other people. Signals are both sent and received in ways that result in suffering.
As currently defined, personality disorders “develop early, are inflexible, and are associated with significant distress or disability.”
Thus, if there are no significant brain injuries or other biological problems, all personality disorders (PD) develop through experience.
This means that during childhood the PD sufferer has received many bad signals (and/or interpreted many signals badly) resulting in their failing to form a coherent well-functioning internal signaling system.
The way to fix this is work with the signals. And the best way to do this is FIML practice. A professional psychotherapist cannot possibly provide this level of treatment.
This brings me to a second point: is there anyone who would not benefit from improving their signaling?
Why do we view psychotherapy as treatment designed merely to make us look and feel “average”? Why don’t we instead work to optimize our psychologies every day?
The Buddha said we are all crazy. We are. We all need to work on our signaling—our personality disorders—all the time.
The distinctions between one PD and another and those who have PDs and those who don’t are vague. This is because all PD problems (absent significant biological deficits, which may include intelligence) are idiosyncratic varieties of signaling malfunctions.
If signaling is the core problem, it should follow that all acquired PD will be classifiable as some kind of signaling malfunction. And that is precisely what we see.
Narcissism is a too simple signaling system. Borderline is an unstable signaling system. Compulsive, passive aggressive, histrionic, avoidant, and so on all are variations of a poorly formed internal signaling system.
The way to study this is through interpersonal semiotics; that is interpersonal semiotic analysis of real-time, real-world communicative signs and symbols.
All people need to do this to optimize their psychologies (their internal signaling systems). Why would anyone not want to do this? Maybe not wanting to do this is the surest sign of PD there is.
The hardest part about doing FIML is finding a willing and able partner. To me, this shows how pervasive bad signaling is. Most people will do almost anything but examine their own signaling with the help of another person.