I'm not a psychiatrist/psychologist or any other kind of mental health expert, but I have a sibling who has been diagnosed with schizo-affective disorder (a psychiatric diagnosis) and Borderline Personality Disorder (a personality/psychological diagnosis). The mental illness (schizo-affective disorder) can be treated with psychotropic drugs, but Borderline Personality Disorder has no pharmaceutical remedy.
Cognitive Behavioral Therapy is frequently recommended for patients with BPD but is costly and works only when the patient acknowledges and understands the Borderline diagnosis and is willing to make the effort to change his/her behaviors. Most Borderlines don't recognize or accept the severity of their personality disorder, so therapy is rarely successful. My sister tried to manipulate a Cognitive Behavioral Therapist who "bought" my sister's tales-of-woe hook, line, and sinker until advised (by me and DH) that my sister's claims were bull@#$%. I suspect that Jodi Arias would likewise manipulate a pricy therapist who might be caught off-guard by Jodi's verbal savvy.
In my humble opinion, Borderline means that an individual does not meet the specific criteria for diagnosis with a psychiatric illness but is not so mentally ill that they cannot function in society. :moo: