He's partially correct. There is really no treatment for personality disorders. You can have certain medication to manage side-effects of the personality disorder (depression/anxiety) or attempt psychotherapy, but there's no actual cure for something like a narcissistic personality disorder.
Although, I want to add that there's been no evidence so far that Caryk has a personality disorder and it's unlikely that she actually does.
Let's just clarify a few things. Personality disorders are quite a broad category and there are certainly effective treatments for many of them, both talking and medication based (although you are correct that medication is often used for secondary symptoms such as anxiety etc.).
Psychopathy is a term derived from the British school of character pathology. In North America the term is "antisocial personality" (or conduct disorder in children). Narcissistic personality is a different entity altogether and there is strong evidence that psychotherapy can be effective in treating this disorder, although it can take time and effort.
As for the antisocial personality, there is NO evidence that any treatment has a positive impact likely due to the fact that it is a neurodevelopment disorder and they lack the brain's "remorse mechanism". The only treatment for severe cases is behavioural (ie. limit their freedom to engage in antisocial acts).
Anyone purposely threatening or harassing someone with the intent of causing them harm is engaging in antisocial behaviour, whether that constitutes a personality disorder is dependant on many other factors.
