Personality Disorders — Clusters, Causes, and Evidence-Based Treatments Explained | Chapter 11 of Essentials of Abnormal Psychology

Personality disorders are enduring, maladaptive patterns of thinking, feeling, and behaving that emerge in adolescence or early adulthood and cause significant impairment. Chapter 11 of Essentials of Abnormal Psychology organizes these disorders into three DSM-5 clusters—A, B, and C—examines their prevalence and risk factors, and reviews effective treatment approaches. This guide will help you master these complex disorders and prepare for your exams.

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Overview of Personality Disorders

Personality disorders affect up to 10% of adults and often co-occur with other mental health conditions. The DSM-5’s categorical approach places them into three clusters based on shared traits, though a dimensional model is also debated. Gender and cultural biases can influence diagnosis, making awareness of these factors crucial.

DSM-5 Clusters A, B, & C

Cluster A (Odd or Eccentric)

• Paranoid Personality Disorder: Pervasive distrust and suspicion of others’ motives.
• Schizoid Personality Disorder: Detachment from social relationships and limited emotional expression.
• Schizotypal Personality Disorder: Social deficits, cognitive distortions, and eccentric behaviors resembling mild schizophrenia.

Cluster B (Dramatic, Emotional, or Erratic)

• Antisocial Personality Disorder (ASPD): Disregard for others’ rights, manipulative behavior, and lack of remorse—often linked to psychopathy.
• Borderline Personality Disorder (BPD): Unstable relationships, self-image, mood swings, impulsivity, and intense fear of abandonment.
• Histrionic Personality Disorder: Excessive emotionality and attention-seeking behaviors.
• Narcissistic Personality Disorder (NPD): Grandiosity, need for admiration, and lack of empathy.

Cluster C (Anxious or Fearful)

• Avoidant Personality Disorder: Extreme sensitivity to criticism, social inhibition, and feelings of inadequacy.
• Dependent Personality Disorder: Excessive need for care, submissive behavior, and fear of separation.
• Obsessive-Compulsive Personality Disorder (OCPD): Preoccupation with order, perfectionism, and control (distinct from OCD).

Causes & Risk Factors

Personality disorders arise from an interplay of genetic, neurobiological, and environmental influences. ASPD and BPD show strong heritability, with abnormalities such as low serotonin in BPD and underactive prefrontal cortex in ASPD. The underarousal hypothesis explains risk-seeking in ASPD, while childhood trauma and poor parental discipline increase vulnerability across clusters.

Treatment Approaches

Effective interventions are cluster-specific and often require long-term therapy:

• Cluster A: Trust-building and social skills training (particularly for schizotypal PD).
• ASPD: Limited efficacy, but CBT can reduce criminal behaviors and improve self-control.
• BPD: Dialectical Behavior Therapy (DBT) is the gold standard, focusing on emotion regulation, distress tolerance, and interpersonal effectiveness.
• NPD: Empathy-building exercises, cognitive restructuring, and self-reflection in therapy.
• Cluster C: CBT for avoidant and dependent PDs; exposure techniques for social inhibition.

Conclusion: Integrating Diagnosis and Treatment

Chapter 11 emphasizes the chronic nature of personality disorders and the need for a nuanced, individualized treatment framework. Understanding clusters, risk factors, and evidence-based therapies will strengthen your clinical skills and exam performance.

For case examples and further insights, watch the full Chapter 11 video summary. Dive deeper into your textbook and reinforce your learning with these frameworks.

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