Personality disorders (PD) are a class of mental disorders characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by the individuals culture. These patterns develop early, are inflexible, and are associated with significant distress or disability. The definitions vary by source and remain a matter of controversy. Official criteria for diagnosing personality disorders are listed in the sixth chapter of the International Classification of Diseases (ICD) and in the American Psychiatric Associations Diagnostic and Statistical Manual of Mental Disorders (DSM). Personality, defined psychologically, is the set of enduring behavioral and mental traits that distinguish individual humans. Hence, personality disorders are defined by experiences and behaviors that deviate from social norms and expectations. Those diagnosed with a personality disorder may experience difficulties in cognition, emotiveness, interpersonal functioning, or impulse control. For psychiatric patients, the prevalence of personality disorders is estimated between 40 and 60%, The behavior patterns of personality disorders are typically recognized by adolescence, the beginning of adulthood or sometimes even childhood and often have a pervasive negative impact on the quality of life.Treatment for personality disorders is primarily psychotherapeutic. Evidence-based psychotherapies for personality disorders include cognitive behavioral therapy, and dialectical behavior therapy especially for borderline personality disorder. A variety of psychoanalytic approaches are also used.Personality disorders are associated with considerable stigma in popular and clinical discourse alike.
DSM-5
The most recent fifth edition of the Diagnostic and Statistical Manual of Mental Disorders stresses that a personality disorder is an enduring and inflexible pattern of long duration leading to significant distress or impairment and is not due to use of substances or another medical condition. The DSM-5 lists personality disorders in the same way as other mental disorders, rather than on a separate axis, as previously.DSM-5 lists ten specific personality disorders: paranoid, schizoid, schizotypal, antisocial, borderline, histrionic, narcissistic, avoidant, dependent and obsessive–compulsive personality disorder. The DSM-5 also contains three diagnoses for personality patterns not matching these ten disorders, but nevertheless exhibit characteristics of a personality disorder:
Personality change due to another medical condition – personality disturbance due to the direct effects of a medical condition. Other specified personality disorder – general criteria for a personality disorder are met but fails to meet the criteria for a specific disorder, with the reason given. Unspecified personality disorder – general criteria for a personality disorder are met but the personality disorder is not included in the DSM-5 classification.These specific personality disorders are grouped into the following three clusters based on descriptive similarities:

Cluster A (odd or eccentric disorders)
Cluster A personality disorders are often associated with schizophrenia: in particular, schizotypal personality disorder shares some of its hallmark symptoms with schizophrenia, e.g., acute discomfort in close relationships, cognitive or perceptual distortions, and eccentricities of behavior. However, people diagnosed with odd-eccentric personality disorders tend to have a greater grasp on reality than those with schizophrenia.