Personality Disorder

Etiology

There are limited high-quality, evidence-based studies focused directly on the etiology of personality disorders, which are complex and multifactorial. Biological factors contribute to the development of personality in multiple ways. Temperament is a heritable and innate psychobiological characteristic that significantly contributes to personality development. [7][8] Temperament lays the framework for an individual's personality development. Personality is a pattern of behaviors that an individual uniquely adapts to address constantly changing internal and external stimuli. Temperament is further shaped through epigenetic mechanisms, namely, life experiences such as trauma and socioeconomic conditions. These are referred to as adaptive etiological factors in personality development.[9][10] Temperament traits include harm avoidance, novelty seeking, reward dependence, and persistence.

Harm avoidance involves a bias towards inhibiting behavior that would result in punishment or non-reward.[11] High harm avoidance results in fear of uncertainty, social inhibition, shy behavior, and avoidance of danger or the unknown. Low harm avoidance is pathological and evident in antisocial personality disorder, histrionic personality disorder, and borderline personality disorder. Novelty seeking describes an inherent desire to initiate new activities likely to produce a reward signal.[12] Low novelty-seeking results in uninquiring, isolative, and stoical behaviors commonly seen in clusters A and C personality disorders; high novelty-seeking is evident in cluster B personality disorders. 

Reward dependence describes the amount of desire to alter behaviors in response to social reward cues.[13] Low reward dependence results in isolative behaviors, with little need for social reward. Persistence describes the ability to maintain behaviors despite frustration, fatigue, and limited reinforcement. Low persistence is associated with indolence, inactivity, and ease of frustration.[13][14] Genetic factors have been attributed as significant contributors to the development of a personality disorder; this was supported by multiple studies that investigated twin, linkage, candidate gene association studies, genome-wide association studies, and polygenic analyses.[7] 

Medical conditions are often associated with personality disorders or personality changes, specifically including those with pathology that may damage neurons. This includes but is not limited to head trauma, cerebrovascular diseases, cerebral tumors, epilepsy, Huntington disease, multiple sclerosis, endocrine disorders, heavy metal poisoning, neurosyphilis, and acquired immune deficiency syndrome (AIDS).[15] Psychoanalytic factors also contribute to the development of personality disorders. Psychoanalyst Wilhelm Reich described "character armor" as defense mechanisms that develop with personality types to relieve cognitive conflict from internal impulses and interpersonal anxiety. For example, individuals with cluster A traits have projection defense mechanisms, and individuals with cluster B traits tend to develop defense mechanisms of displacement, denial, projection, rationalization, and regression.[16]

Epidemiology

The World Health Organization has estimated the prevalence of having a personality disorder to be 6.1%.[17] The estimated prevalence of the 3 clusters (A, B, and C) are 3.6%, 1.5%, and 2.7%, respectively.[5] Within the psychiatric population, estimates for the prevalence of personality disorders can reach up to 30% and even higher in incarcerated populations.[18] Those with personality disorders are likely to be younger, unmarried, men of lower socioeconomic status, and lower education levels.[19] These findings are likely congruent with certain personality disorders known to be partially self-resolving or at least decreasing symptom severity with age.[20]

Pathophysiology

Limited high-quality, evidence-based investigations of neuroimaging and histopathological findings among personality disorders exist. Some studies propose that there is a genetic link between schizophrenia and cluster A personality disorder, forming a spectrum of schizophrenia-like illnesses; however, the current clinical understanding of the relationship between cluster A personality disorders and schizophrenia is limited.[21] Some biological correlates and physiological findings have been associated with cluster B personality disorders. Most of this research relates to antisocial personality disorder (and psychopathy) in studies of individuals in correctional settings. Underarousal of the autonomic nervous system has been hypothesized as a pathophysiological mechanism for antisocial personality disorder. This hypothesis proposes that individuals with antisocial personality disorder (ASPD) require higher sensory input to produce normal brain functioning than normal subjects, causing affected individuals to seek higher sensory input to raise their arousal to more tolerable levels. The result may be a higher risk tolerance for situations with higher arousal.[22][23] Findings to support this suggestion are lower pulse rates, lower skin conductance, and increased amplitude on event-related potentials in patients with antisocial personality disorder.[24][25] Nearly 50% of individuals with ASPD disorder exhibit various electroencephalogram (EEG) abnormalities, including more slow-wave activity.[23][26]

Researchers have also discovered abnormal central nervous system (CNS) functioning associated with ASPD on nervous system imaging. The prefrontal cortex, the superior temporal cortex, the amygdala-hippocampal complex, and the anterior cingulate cortex are likely involved.[27] In 1991, Raine published a study comparing 21 individuals with ASPD to 34 control subjects that showed reduced prefrontal gray matter in the subjects with ASPD compared to control subjects on structural magnetic resonance imaging (MRI).[28] Grant reported a study comparing 18 men with ASPD and psychopathy to healthy controls that showed individuals with ASPD had a smaller orbitofrontal cortex volume on structural MRI.[29]

Current neurobiological models of borderline personality disorder link findings across neuroendocrinology, structural neuroimaging, and functional neuroimaging. Specific genes may be involved with disruptions in the hypothalamic-pituitary-adrenal axis consistent with stress-related changes and chronic elevation of cortisol, affecting emotional regulation and impulse control.[30] Neuroimaging studies have identified differences in the amygdala, hippocampus, and medial temporal lobes in patients with borderline personality disorder that may also be related to self-reported childhood trauma.[31][32]

Top-down control abnormalities are seen in borderline personality disorder, showing that cortical activity to moderate the amygdala (and other limbic areas) is impaired. Instead, behavior is driven from the bottom-up, meaning that amygdala activation is unmoderated by higher-level cortical functions.[33] Studies also suggest that patients with borderline personality disorder may misattribute negative emotions (fear, anger, disgust) to neutral faces more than control patients despite having the perception of happy and upset faces equivalent to those groups.[34] On neuropsychological testing, patients with borderline personality disorder have impaired cognitive flexibility and increased impulsivity. No correlation was found between borderline personality disorder disorder symptom severity and cognitive function.[35][36]

The pathophysiology of cluster C personality disorders is poorly understood. Although obsessive-compulsive disorder and obsessive-compulsive personality disorder are separate conditions, they have intersecting traits. There is a hypothesis stating that in obsessive-compulsive personality disorder, there is a disruption in serotonergic neurotransmission similar to that seen in obsessive-compulsive disorder.[37] Neuroimaging has revealed anomalies in brain areas related to decision-making, emotional modulation, and habit formation. These studies emphasize the prefrontal cortex and the amygdala. However, the findings are preliminary, and more research is needed to understand the neurobiological aspects of obsessive-compulsive personality disorder and other cluster C personality disorders.[38]

History and Physical

The presentation of personality disorders is broad and variable. Further, each personality is unique due to the extensive spectrum of temperament variation and life experiences endured by individuals that shape their personality. Those with personality disorders may bear grudges, hold strong first impressions, have poor boundaries, or be distrustful of clinicians they encounter. Therefore, an individualized approach is needed in the evaluation of a patient with a suspected personality disorder to maintain therapeutic rapport, establish trust, and maintain safe and appropriate boundaries. 

The chief complaint is likely to relate to psychiatric sequelae of an underlying personality disorder, such as depression, anxiety, impulsive behaviors, and substance abuse. Additional complaints may relate to psychosocial impairments resulting from the underlying personality disorder, including difficulties with interpersonal relationships, unsatisfactory academic history, and poor vocational performance.[39] Obtaining a thorough psychiatric history, medical history, social history, developmental history, and history of family dynamics is essential for diagnosis. The features of personality disorders typically start emerging in adolescence, and worsening pathological behaviors may increase through early adulthood before they become an inflexible pattern of thinking and action. Inquiring about the patient's capacity to make and maintain relationships with family, friends, and romantic partners can help clarify the personality disorder diagnosis.[40] 

The mental status examination is crucial in assessing individuals for personality disorders. The specific elements and findings of the examination can vary depending on each case. Assessment of patients should include the following:

• Appearance: A general description of how the patient looks during the interview. Those with identity difficulties may have excessive or eccentric clothing or accessories. Poor grooming and hygiene levels can suggest problems with goal-driven behavior or poor persistence.            
• Attitude and behaviors: A general description of how the patient acts during the interview, including various levels of cooperation, disinhibition, and regression. Attitude can describe interest level, candidness, shyness, fearfulness, or grandiosity. The level of eye contact can be observed, which varies in personality disorders, particularly in those individuals with poor social interest. Document negative signs, such as avolition (lack of motivation), asociality (lack of desire for relationships), and alexithymia (lack of emotions).                                                                            
• Affect: Describe the quality and range of affect displayed by the individual. Some descriptions are angry, euthymic, dysphoric, irritable, euphoric, sad, or irritable.
• Speech: Abnormalities include odd, vague, metaphorical, or stereotyped speech. Individuals with personality disorders may have more pauses, slower speech, and less pitch variability.
• Thought content: Assess for auditory/visual/olfactory/tactile hallucinations, delusions, and thoughts of self-harm, suicidality, or harming others. Delusions can be grandiose, erotomanic, jealous, somatic, or persecutory/paranoid. Hallucinations are not characteristic of personality disorders and, if present, need further clinical investigation for diagnostic clarity. Transient paranoia is frequently associated with borderline personality disorder, but auditory hallucinations are not a primary symptom. Illusions can be present in certain personality disorders, particularly schizotypal personality disorder. Depersonalization and derealization can be present in personality disorders, particularly borderline personality disorder.                                 
• Thought process: This process describes how thoughts are formulated, organized, and processed. Document if the patient is clear and coherent or confused, tangential, loose, or disorganized. 
• Insight: Generally, individuals with personality disorders have a poor understanding of how their behaviors are related to their feelings, dysregulated emotions, and interpersonal difficulties. Insight can be fair or good in certain personality disorders despite persisting symptoms. 
• Judgment and impulse control: Poor judgment and poor impulse control are common in personality disorders and range in severity depending on the individual.[41]

Evaluation

Diagnosis of a personality disorder is based on the longitudinal observation of an individual's behaviors to assess their functioning over time. The symptoms of a personality disorder may overlap with symptoms observed during acute psychiatric conditions such as mood disorders or substance use disorders. If possible, personality disorders should be diagnosed when there is not a concurrent acute psychiatric condition.[42] Personality disorders can also contribute to the exacerbation of another psychiatric illness and lead to hospitalization.[43]

Clinicians often develop a psychological reaction to individuals with personality disorders, which is known as "countertransference." This occurs due to the nature of the encounters, as individuals may be irritable, aggressive, suicidal, or engage in self-harm.[44] Clinicians must recognize signs of countertransference, which can negatively affect patient care.[45] When clinicians feel frustrated with patients who may have a personality disorder, it is helpful to use those feelings as an evaluation tool to guide diagnosis and treatment.[46][47]

Psychological testing can help diagnose personality disorders but is not generally needed for a clinical diagnosis when a sufficient history is available. The Minnesota Multiphasic Personality Inventory-2 and the Rorschach Perceptual Thinking Index may be used to verify the presence of a personality disorder.[48][49][50] To formally diagnose a personality disorder, individuals must meet the diagnostic criteria specified in the DSM-5-TR. The diagnosis requires a thorough evaluation that considers multiple sources of information, including personal history, collateral information, and a mental status examination. A comprehensive assessment allows clinicians to assess the individual's symptoms, functioning, and overall presentation to see if diagnostic criteria are met. Specific DSM-5-TR criteria exist for each specified personality disorder. There is also a DSM-5-TR diagnosis for general personality disorder.

DSM-5-TR Criteria for General Personality Disorder

• An enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual's culture. This pattern is manifested in 2 (or more) of the following areas:
  • Cognition (ie, ways of perceiving and interpreting self, other people, and events)
  • Affectivity (ie, the range, intensity, lability, and appropriateness of emotional response)
  • Interpersonal functioning
  • Impulse control
• The enduring pattern is inflexible and pervasive across various personal and social situations.
• The enduring pattern leads to clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The pattern is stable and of long duration, and its onset can be traced back at least to adolescence or early adulthood.
• The enduring pattern is not better explained as a manifestation or consequence of another mental disorder.
• The enduring pattern is not attributable to the physiological effects of a substance (eg, a drug of abuse, a medication) or another medical condition (eg, head trauma).

The DSM-5-TR introduced an alternative diagnostic model for personality disorders in the Emerging Measures and Models section. The alternative diagnostic model for personality disorders in the DSM-5-TR is a hybrid dimensional-categorical model that defines personality disorders in terms of impairments in personality functioning and pathological personality traits.

Alternative DSM-5 Models for Personality Disorders: General Criteria for Personality Disorder

The essential features of a personality disorder include:

• Moderate or greater impairment in personality (self/interpersonal) functioning
• Having 1 or more pathological personality traits 
• The impairments in personality functioning and the individual's personality trait expression are relatively:
  • Inflexible and pervasive across a broad range of personal and social situations
  • Stable across time, with onsets that can be traced back to at least adolescence or early adulthood
  • Not better explained by another mental disorder
  • Not solely attributable to the physiological effects of a substance or another medical condition (eg, severe head trauma)
  • Not better understood as normal for an individual's developmental stage or sociocultural environment

Treatment / Management

Attention to the therapeutic alliance is crucial, no matter the treatment paradigm one adopts. Individuals with personality disorders may be provocative, aggressive, or irritable, and the clinician's thoughts and feelings (countertransference), as well as the treatment team's reactions, must be monitored closely. No standard treatment algorithm exists for most personality disorders. Frequently, patients with personality disorders present due to comorbid psychiatric conditions, which can benefit from appropriate treatment. In the absence of a comorbid psychiatric illness, only poor evidence exists that pharmacotherapy helps treat personality disorders, and there are no Food and Drug Administration-approved medications for specific personality disorders. With the exception of borderline personality disorder, there are no high-quality, evidenced-based psychotherapies for personality disorders.[51]

Often, individuals request treatment at the behest of a first-degree relative or friend. Generally, this occurs after maladaptive behaviors have created stress on another rather than internal distress from the individual with a personality disorder. Therefore, assessing the treatment goals in each specific case is essential. As personality disorders may not remit, the focus of treatment may be reducing interpersonal conflict and stabilizing psychosocial functioning.[52][53] Case management can assist patients with personality disorders in maintaining income, shelter, and connection to medical and mental health services and providing assistance with other basic needs.(A1)

Differential Diagnosis

Personality disorders are often comorbid with other psychiatric disorders, and many features of specific personality disorders resemble other psychiatric illnesses. The defining characteristics of personality disorders that appear before early adulthood are an enduring pattern of behavior that is inflexible and pervasive across a broad range of personal and social situations and does not occur exclusively during an episode of another mental disorder.[20] These characteristics can help distinguish personality disorders from episodic psychiatric illnesses, such as a major depressive episode, an anxiety disorder, or a manic episode.[54] Transient paranoia and psychosis are possible in certain personality disorders (primarily borderline personality disorder, schizotypal personality disorder, and paranoid personality disorder). Frank and persistent psychosis is not consistent with a personality disorder.[55]

After extreme stress, an individual's personality can change, and a diagnosis of posttraumatic stress should be considered. A personality disorder diagnosis should not be made when there are behaviors connected with substance intoxication or withdrawal or behaviors that are associated with sustaining substance use. Medical conditions are often associated with personality disorders or personality changes, specifically including those with pathology that may damage neurons. This includes but is not limited to head trauma, cerebrovascular diseases, cerebral tumors, epilepsy, Huntington disease, multiple sclerosis, endocrine disorders, heavy metal poisoning, neurosyphilis, and acquired immune deficiency syndrome (AIDS).[15] In these instances, a diagnosis of personality change due to another medical condition should be considered; an individual may have personality traits that do not reach the threshold for a personality disorder.

Pertinent Studies and Ongoing Trials

Experts in personality disorders have suggested switching to a dimensional model of personality rather than a cluster model. The dimensional models proposed generally describe temperament, utilization of defense mechanisms, and identifying pathological personality traits.[4] The DSM-5-TR introduced an alternative diagnostic model for personality disorders in the Emerging Measures and Models section; this includes a hybrid dimensional-categorical model that defines personality disorders in terms of impairments in personality functioning and pathological personality traits.

Prognosis

The prognosis of personality disorders varies depending on the specific personality disorder. Patients with borderline personality disorder have a fair prognosis, and studies demonstrate that borderline personality disorder psychopathology improves more than generally expected but that psychosocial functioning often remains impaired. Systematic meta-analysis with 5- to 15-year follow-up periods showed mean remission rates of 60%.[56] Despite high rates of remission and low rates of relapse, patients with borderline personality disorder have severe and persistent impairment in functional and social recovery. This is consistent with the theory that with stable support and avoidance of interpersonal stressors, patients with borderline personality disorder remit clinically.[56] 

Individuals with antisocial personality disorder typically have severe pathology for life. However, in patients who achieve remission, the mean age is 35, and remission is predicted by less baseline symptomatology. Other factors that predict improved outcomes are older age at presentation, improved community ties, job stability, and marital attachment.[57][58][59] Other personality disorders have variable remission rates, and factors associated with remission (such as treatment and social stability) are poorly understood. 

Complications

Substance use disorders are common among personality disorders but it is not clear which personality disorders pose the most risk for a particular substance use disorder.[60] Personality disorders have an increased likelihood of suicide and suicide attempts compared to those without personality disorders, and individuals with personality disorders should be screened for suicidal ideation regularly.[61]