PSYX 340 Psychological Disorders · Unit 3: Psychosis, personality and childhood · on Exam 3
3.4 Personality disorders
Study notes for Personality disorders in PSYX 340 Psychological Disorders at Montana State University: the big ideas, a worked example, common mistakes and an exam tip. The same topic has endless practice questions and flashcards in Mathub.
Big ideas
- A personality disorder is an enduring, inflexible pattern of inner experience and behavior that deviates from cultural expectations, begins by adolescence or early adulthood and causes distress or impairment. DSM-5-TR groups the ten disorders into three clusters.
- Cluster A (odd or eccentric): paranoid (pervasive distrust), schizoid (detachment, restricted emotion) and schizotypal (odd beliefs and perceptions, eccentric behavior, social discomfort; related to schizophrenia).
- Cluster B (dramatic, emotional, erratic): antisocial (disregard for others’ rights; age 18 or older with evidence of conduct disorder before 15), borderline (instability in relationships, self-image and mood, impulsivity, self-harm, fear of abandonment), histrionic (excessive emotion and attention-seeking) and narcissistic.
- Cluster C (anxious or fearful): avoidant (feels inadequate, fears rejection), dependent (needs to be taken care of) and obsessive-compulsive personality disorder (preoccupied with order, perfectionism and control; different from OCD, which has true obsessions and compulsions).
- Treatment: dialectical behavior therapy (DBT), developed by Marsha Linehan, has the strongest support for borderline personality disorder; mentalization-based therapy also helps. Antisocial personality disorder responds poorly to treatment. DSM-5-TR Section III offers an alternative dimensional model rating personality functioning and traits.
Worked example
Sort into clusters: a woman who fears others are plotting against her; a man who cannot make any decision without his partner’s reassurance; a teen-turned-adult with a long history of lying, fights and no remorse.
Show the solution
Suspicion and distrust is paranoid (Cluster A). Needing others to decide and take care of him is dependent (Cluster C). Lying, aggression and no remorse since adolescence (with conduct disorder before 15, and now 18 or older) is antisocial (Cluster B).
Common mistakes
- Diagnosing antisocial personality disorder in someone under 18. Use conduct disorder instead.
- Confusing obsessive-compulsive personality disorder (perfectionism and control) with OCD (obsessions and compulsions).
- Using “psychopathy” as an exact synonym for antisocial personality disorder. They overlap but are not identical.
Exam tipMemorize the clusters with “weird, wild, worried” (A, B, C). Then learn one signature feature for each of the ten disorders.
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