In brief - Antisocial Personality Disorder (impulsive, aggressive, manipulative) Avoidant Personality Disorder (shy, timid, "inferiority complex") Borderline Personality Disorder (impulsive, self-destructive, unstable) Dependent Personality Disorder (dependent, submissive, clinging) Histrionic Personality Disorder (emotional, dramatic, theatrical) Narcissistic Personality Disorder (boastful, egotistical, "superiority complex") Obsessive-Compulsive Personality Disorder (perfectionistic, rigid, controlling) Paranoid Personality Disorder (suspicious, distrustful) Schizoid Personality Disorder (socially distant, detached) Schizotypal Personality Disorder (odd, eccentric) - but in reality personally pervasive, hard to diagnose and treat, and isolating. Most psychiatrists will not see such patients. Social conventions are often means of manipulation for sufferers. A personality disorder can go unnoticed by clinicians, but is usually experienced by the family - as one book title describes it, "I Hate You, Don't Leave Me." Many prisoners suffer from one or more of the personality disorders. Not listed is Dissociative Identity Disorder (formerly Multiple Personality Disorder). These folks are generally meek and unstable, having been subjugated as children to extreme sexual, physical, emotional and/or abandonment abuse. I believe the incidence of personality disorders in society is large (approaching 10%) and is either increasing or being more effectively diagnosed. The most common is the borderline personality disorder, sometimes co-occurring with bipolar disorder. See http://www.nami.org/Template.cfm?Section=By_Illness&Template=/TaggedPage/TaggedPageDisplay.cfm&TPLID=54&ContentID=23040 [Broken]. Someone you encounter who is not just "crazy," but whose relationships are maladaptive and seek predominantly their own benefit may have a personality disorder. What is your experience with people who behave in this manner?