The diagnosis itself is not necessarily disqualifying, but the history that established that diagnosis may be:
Decision Considerations - Aerospace Medical Dispositions
Item 47. Psychiatric Conditions - Personality Disorder
The category of personality disorders severe enough to have repeatedly manifested itself by overt acts refers to diagnosed personality disorders that involve what is called "acting out" behavior. These personality problems relate to poor social judgment, impulsivity, and disregard or antagonism toward authority, especially rules and regulations.
A history of long-standing behavioral problems, whether major (criminal) or relatively minor (truancy, military misbehavior, petty criminal and civil indiscretions, and social instability), usually occurs with these disorders. Driving infractions and previous failures to follow aviation regulations are critical examples of these acts.
Certain personality disorders and other mental disorders that include conditions of limited duration and/or widely varying severity may be disqualifying. Under this category, the FAA is especially concerned with significant depressive episodes requiring treatment, even outpatient therapy. If these episodes have been severe enough to cause some disruption of vocational or educational activity, or if they have required medication or involved suicidal ideation, the application should be deferred or denied issuance.
Some personality disorders and situational dysphorias may be considered disqualifying for a limited time. These include such conditions as gross immaturity and some personality disorders not involving or manifested by overt acts.
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So yeah, if you actually seriously screwed up in life and demonstrated that you don't give a fly in' $;:@ if you hurt people, your odds aren't great. If you simply PO'd a single shrink, heck, 80% of shrinks would have been seriously PO's to find that you had voted for the winner in the 2016 presidential election, some willing to testify in court that you are sociopathic for doing so.
Besides, everyone is entitled to a second opinion.