There doesn't seem to be a cure for any of the personality disorders (part of the reason they are categorized that way) at this time. However, symptoms can be mitigated (IF they are truly open to treatment which is a problem with quite a bit of the personality disorders) primarily with CBT and hard work at changing the way you perceive and react to everything.
Medications used on people with personality disorders are usually only used to deal with peripheral (or comorbid) symptoms like depression (antidepressants, stimulants), anxiety (benzos, beta-blockers, etc), anger/aggression (typical and atypical antipsychotics). Also mood stabilizers.
Personality disorders are not caused by chemical imbalances in the brain; although we still have a great deal more to learn about PDs, the biggest culprit apparent so far is one's experiences growing up. There are no meds that can treat the personality disorder itself because it is about maladaptive or abnormal perceptions of reality, thought patterns, and behaviors. No drugs have been invented yet that can alter these things. By the time these people get to doctors as adults, they have been set in their ways since their teens and their brain is a bit hard-wired for their particular disorder.
Very inflexible and difficult to change; we are talking about personality traits that we see as abnormal, relative to cultural norms. Try to think about how hard it would be for you to alter one of your personality traits. If you're a generally humble or self-effacing person, try to imagine how difficult it would be to alter this behavior to something a little more prideful; not pretending to be proud and overriding your impulse for be humble, but to actually abolish the humble impulse and replace it with the proud impulse. Completely change your default position. Very very difficult for adults to do, takes a lot of time and constant effort.
The personality disorders are probably the most difficult to treat because it requires patient willingness and cooperation (quite a bit do not believe there is something wrong with them or that it's so bad they need treatment) and steadfast commitment to therapy (lots of people stop therapy after just a few months). But more importantly the goal is to change the way someone thinks and reacts.
Btw, there is no real pattern suggesting personality disorders inherently worsen with time.
People with NPD will not normally seek therapy on their own (they are unlikely to believe they have a problem, nor do the majority cause others such harm that would compel treatment or at least make it obvious to the patient that they need help). But they can be talked into trying therapy by friends and family. If you try this I suggest you present a very logical, calm argument and make sure you have some evidence to back up things you say in case he challenges your point of view.
And Tom was spot on.
Edited by Duchykins, 06 July 2015 - 05:16 AM.