Normal people don’t generally tend to share their health or mental health diagnosis with other people just out of the blue like that. It’s certainly weird.
I mean, first of all, most mental health professionals aren’t going to just blurt out that label in therapy; most therapists are going to focus on the patient’s behavior, emotions, and thoughts rather than go straight to labeling them.
Second, what kind of braggable thing is it, to be diagnosed with a personality disorder? Why would someone share this with anyone outside a close circle of trusted people? What response were they expecting from you? It’s just very odd for someone to say that about themselves.
If you are dealing with a covert narcissist, or a narcissist with co-morbid diagnoses, it’s possible that they are using this one ‘nugget’ of truth to draw you in, manipulate you, or attempt to skew your perceptions in some way. I mean, look how much time you’re giving to this declaration already—they’ve hooked you in, you’re thinking about them, you’re wondering about them, you’re doing research and reaching out to strangers on the internet to try and figure out this fascinating character. They are front-and-center in your expenditure of time, focus, and energy. That’s narcissistic supply, baby!
Honestly, there is really no telling why someone would say something like that; it’s a safe bet that anyone doing that kind of self-disclosure is damaged in some way, but if I was going to guess, I’d say they skewed more toward histrionic or borderline, one of the other Cluster B[1] disorders.
I suggest that you don’t give too much more of your time, energy, or thought to this person and their problem personality, whatever it may be. They have revealed to you that they are, or believe that they are, a disordered individual with a mental health diagnosis that is destructive to both self and others.
How much more time do you want to spend around a person who has come right out and told you that they’re toxic?
Footnotes
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