Difficulty: Intermediate | Prerequisites: Part 1 of these notes (overview and Cluster A), basic understanding of emotion regulation and psychotherapy approaches.
Cluster B is the "dramatic-emotional" group of personality disorders. These are among the most heavily tested personality disorders in abnormal psychology courses because they involve high comorbidity, significant interpersonal disruption, and, in the case of borderline personality disorder, a robust evidence base for treatment (dialectical behaviour therapy). This section covers borderline, histrionic, and narcissistic personality disorders. You should understand each disorder's core features, how they overlap with one another, their theoretical explanations, and the treatment landscape. Antisocial personality disorder also belongs to Cluster B but is not covered in these notes (it may be addressed in a separate chapter in your textbook).
This is Part 2 of 3.
Cluster B disorders share dramatic, impulsive behaviour and a lack of concern for others. Borderline personality disorder centres on emotional dysregulation, identity instability, and fear of abandonment. Histrionic personality disorder involves attention-seeking and rapidly shifting emotions. Narcissistic personality disorder is defined by grandiosity, need for admiration, and lack of empathy. Treatment options vary widely in evidence base, with borderline having the most researched interventions.
Cluster B
The "dramatic-emotional" personality disorder cluster. Core feature across all Cluster B disorders: lack of concern for others, combined with dramatic and impulsive behaviour.
Borderline personality disorder (BPD)
A personality disorder characterised by out-of-control emotions, hypersensitivity to abandonment, identity disturbance, impulsive self-damaging behaviour, and unstable interpersonal relationships. In simple terms, people with BPD experience emotional storms they cannot calm, swing between idealising and devaluing others, and struggle with a shifting sense of who they are.
Splitting
A defence mechanism associated with BPD in which a person views themselves and others as entirely good or entirely bad, with little ability to integrate these views. Leads to instability in emotions and relationships.
Dialectical behaviour therapy (DBT)
A psychotherapy developed by Marsha Linehan specifically for BPD. Combines cognitive-behavioural techniques with mindfulness and distress tolerance strategies to help clients regulate emotions, correct dichotomous thinking, and improve interpersonal skills.
Mentalization-based treatment (MBT)
A psychodynamic therapy for BPD based on the idea that patients have difficulty understanding mental states (their own and others') due to early traumatic attachment experiences. Provides support and validation while helping patients develop alternative perspectives.
Transference-focused therapy (TFT)
A psychodynamic approach for BPD that uses the patient-therapist relationship to develop more realistic self-understanding and healthier interpersonal patterns.
Histrionic personality disorder (HPD)
A personality disorder characterised by pervasive attention-seeking behaviour, rapidly shifting emotions, and unstable relationships. Shares features with BPD but centres on the need for attention rather than fear of abandonment.
Narcissistic personality disorder (NPD)
A personality disorder defined by grandiosity, preoccupation with self-importance, need for admiration, and lack of empathy. Distinguishing feature from HPD is the grandiosity.
Engage in behaviours that are dramatic and impulsive
Show little regard for their own safety or the safety of others
May act in hostile or violent ways toward others
Lack of concern for others is the core shared feature
Clinical picture:
Out-of-control emotions that the person cannot smooth or regulate
Hypersensitivity to abandonment; misinterpret everyday actions of others as rejection or desertion
Tendency to cling tightly to other people; describe an inner emptiness that drives them to attach to new acquaintances or therapists to fill that void
History of hurting oneself; engage in impulsive, self-damaging behaviours
Fundamental deficits in identity: self-concept is distorted and unstable, with periods of extreme self-doubt alternating with grandiose self-importance
Prone to transient dissociative states (feeling unreal, losing track of time, forgetting who they are)
Unstable interpersonal relationships: switch from idealising others to despising them with minimal provocation
Mood is unstable, with bouts of depression, anxiety, or anger arising frequently and seemingly without cause
Variety of symptoms and their shifting nature make BPD difficult to treat and diagnose
Usually diagnosed with another disorder as well: substance abuse, depression, generalised anxiety disorder, simple phobia, agoraphobia, PTSD, or somatisation disorder
Higher suicide rates, especially in the first year or two after diagnosis (likely because diagnosis often coincides with a crisis period)
Demographics and course:
Slightly more common in women than men
More common in people of colour than in white populations
More common in lower socioeconomic classes
Hispanics more likely than white or Black individuals to be diagnosed, possibly due to genuine risk-factor prevalence or clinician failure to account for cultural norms around emotional expression
Chronic and intractable, but recent studies show higher rates of remission within 10 to 15 years
Only a minority in remission relapse
Ability to hold a job improves, but stable, positive social relationships remain difficult
Stressful life events and lack of social support are triggers for relapse
Theories of BPD
Emotion regulation deficits: greater variability in moods (particularly hostility, fear, sadness), more negative emotional baseline, more emotional variability, and slower return to emotional baseline
Cognitive theories:
Hyperattentive to negative emotional stimuli
Memories tend to be more negative
Negative biased interpretations of situations
Attempt to suppress negative thoughts but fail, leading to impulsive acting out
Combination of emotional and cognitive dysfunction disrupts interpersonal behaviour: more negative views of others and relationships, poor empathy, poor social problem-solving
Childhood factors:
Childhood marked by instability, neglect, and parent psychopathology
History of physical and sexual abuse during childhood
Linehan suggests that exposure to abuse, neglect, and criticism by significant others makes it difficult to learn emotion-regulation skills and to understand and accept one's own emotional reactions
Individuals rely on others to cope but lack self-confidence to ask for help maturely, so they become manipulative and indirect; extreme emotional reactions lead to impulsive actions
Psychoanalytic theories:
Never fully differentiated their view of self from their view of others, making them extremely reactive to others' opinions and the possibility of abandonment
When they perceive rejection, they reject themselves and may engage in self-punishment or self-mutilation
Unable to integrate positive and negative qualities of self-concept or concept of others (splitting), because early caregivers rewarded dependence and compliance but were hostile when the child tried to separate
Neurobiology:
Amygdala and hippocampus are smaller in volume
Greater activation of the amygdala
Structural and metabolic abnormalities in the prefrontal cortex (which regulates emotional reactions and impulse control)
Neurobiological differences may be genetic; disorder runs in families, and twin studies show heritability
Early abuse and maltreatment are associated with changes in the structure and organisation of the amygdala and hippocampus, which may explain the link between childhood abuse and BPD deficits
Treatment of BPD
Dialectical behaviour therapy (DBT):
Most researched psychotherapy for BPD
Helps client gain a more realistic and positive sense of self
Teaches adaptive problem-solving skills and emotion regulation
Corrects dichotomous (black-and-white) thinking
Client learns to monitor self-disparaging thoughts and challenge them
Assertiveness skills for close relationships
Impulse control through monitoring situations and learning alternative responses
Evidence: reduces depression, anxiety, and self-mutilating behaviour; increases interpersonal functioning
Systems training for emotional predictability and problem solving (STEPPS):
Group cognitive-behavioural intervention
Challenges irrational and maladaptive cognitions; addresses self-management and problem-solving
Evidence: improvement in negative affect, impulsivity, functioning, and mood; reduction in hospitalisation and suicide attempts
Psychodynamically oriented therapies:
Transference-focused therapy: uses the therapist-patient relationship to develop more realistic self-understanding and healthier interpersonal relationships. Evidence: reductions in suicide, impulsivity, aggression, and anger.
Mentalization-based treatment: based on the idea that BPD patients have difficulty understanding mental states due to traumatic childhood experiences and poor attachment. Provides support and validation; helps patients develop alternative perspectives on self and others. Evidence: improvement in mood and functioning, fewer medication needs, fewer suicide attempts.
Medications:
Mood stabilisers (e.g., aripiprazole, lamotrigine)
Atypical antipsychotics (e.g., olanzapine)
No evidence that SSRIs improve mood or reduce aggressiveness and impulsiveness in BPD
Adding medication to psychotherapy does not appear to improve overall treatment effectiveness
Clinical picture:
Shares features with BPD: rapidly shifting emotions and intense, unstable relationships
Distinguishing feature: pervasive attention-seeking behaviour across situations
Wants flattering nurturance and preferential attention
Overly trusting of and influenced by authority figures
Pursues attention by being highly dramatic, overtly seductive, and flamboyantly emphasising appearance
Perceived by others as self-centred, shallow, unable to delay gratification, demanding, and overly dependent
Alienates friends with constant demands for attention
More common in women than men
More likely to be separated or divorced than married
Tends to exaggerate medical problems and makes more medical visits than average
Increased rate of suicidal threats and behaviour, used to coerce attentive caregiving
Often seeks treatment for depression or anxiety
Theories of HPD
Little is known about the causes
Some evidence of family linkage, but genetic linkage is unclear
Treatment of HPD
Psychodynamic treatments: focus on uncovering repressed emotions and needs, then helping express them in socially appropriate ways
Cognitive therapy: identifying assumptions that the client cannot function independently; helping formulate goals that do not depend on others' approval; toning down dramatic evaluations of situations. Evidence: reductions in depression and interpersonal difficulties.
None of these therapies have been empirically tested in controlled studies
Clinical picture:
Similar to HPD in dramatic manner, admiration-seeking, and shallow emotional expression and relationships
Distinguishing feature: grandiosity
Preoccupied with thoughts of self-importance and fantasies of power and success
View themselves as superior
Make entitled demands, ignore or devalue the needs of others, exploit others for power, and are arrogant and condescending
Unlike BPD, do not experience the same abandonment concerns despite needing admiration
Can be successful in societies that reward self-confidence and assertiveness
Grossly overestimate their abilities, which eventually leads to failures
Annoy and alienate important people in their lives
Seek treatment for depression and trouble adjusting to life stressors
More common in younger adults, which supports the idea that NPD may be increasing due to social and economic conditions that promote self-focused individualism
High rates of substance abuse, mood, and anxiety disorders
Increased rates of physical and sexual aggression, impulsivity, homicidal thoughts, and suicidal behaviours
Theories of NPD
Psychodynamic: maladaptive strategies for managing emotions and self-views. Did not develop a realistically positive self-view or adaptive coping strategies as children, so they rely on praise and domination of others for self-esteem.
Cognitive: developed unrealistically positive assumptions about self-worth due to childhood indulgence and overvaluation by significant others. Alternatively, the belief in being unique or exceptional may serve as a defence against rejection or unmet emotional needs. Significantly more likely to endorse beliefs that they are not bound by rules.
Pincus and Lukowitzky: narcissism can present as grandiose or vulnerable.
Grandiose type: copes with self-esteem difficulties by viewing the self as superior and engaging in grandiose fantasies. Entitled, exploitative, envious, and aggressive, especially under stress. May engage in criminal activities or violent acts.
Vulnerable type: copes by engaging in grandiose fantasies to manage intense shame. Hypersensitive to rejection and criticism, leading to avoidance of others.
NPD is associated with childhood adversity: physical abuse, neglect, and having a parent who was abused or had a mental health problem
Treatment of NPD
Tend not to seek treatment unless they develop depression or encounter severe interpersonal problems
View problems as weakness and blame others
Pose significant challenges to therapeutic alliance
Collaborative cognitive approach: help develop more realistic expectations of abilities; increase sensitivity to others' needs by challenging self-aggrandising interpretations
Patients often leave therapy once their acute problem (e.g., depression) resolves
No systematic psychotherapy or medication treatment studies have been published for NPD (same gap as HPD)
Borderline personality disorder is one of the most commonly encountered diagnoses in psychiatric emergency settings, partly because of the associated self-harm and suicidality. DBT, originally developed for BPD, has since been adapted for eating disorders, substance use disorders, and treatment-resistant depression, making it one of the most influential therapeutic developments of the past several decades. Narcissistic traits are increasingly discussed in popular culture (e.g., "narcissistic abuse"), but it is worth keeping the clinical definition separate from colloquial usage.
Students often confuse BPD with bipolar disorder because both involve mood instability. BPD mood shifts happen rapidly (within hours) and are usually triggered by interpersonal events, whereas bipolar episodes last days to weeks and follow a different neurobiological pattern.
A common mistake is assuming that BPD is untreatable. Evidence-based treatments (DBT, MBT, TFT, STEPPS) show meaningful improvement, and recent research shows significant remission rates over 10 to 15 years.
Students sometimes conflate histrionic and narcissistic personality disorders. The distinguishing feature is grandiosity in NPD: narcissistic individuals believe they are superior, while histrionic individuals are seeking attention and validation without the same inflated self-evaluation.
Adding medication to psychotherapy for BPD does not improve outcomes. This is counter-intuitive and frequently tested.
⚠️ Know the core features and distinguishing characteristics of BPD, HPD, and NPD.
⚠️ Be able to explain splitting and its role in BPD relationships and self-concept.
⚠️ Understand the biopsychosocial model of BPD: emotion dysregulation, cognitive biases, childhood abuse, psychoanalytic underpinnings, and neurobiology (amygdala, hippocampus, prefrontal cortex).
⚠️ Know DBT in detail: what it targets, its techniques, and its evidence base. Also know MBT, TFT, and STEPPS at a summary level.
⚠️ Medication for BPD: mood stabilisers and atypical antipsychotics may help, but SSRIs do not, and drugs added to psychotherapy do not improve outcomes.
⚠️ HPD and NPD both lack empirically tested treatment studies. This is a testable gap.
⚠️ Grandiose vs. vulnerable narcissism (Pincus and Lukowitzky) is a commonly tested distinction.
True or False: BPD mood shifts typically last days to weeks, similar to bipolar disorder.
Fill in the blank: The defence mechanism in which BPD patients see themselves and others as entirely good or entirely bad is called _______.
True or False: Adding SSRIs to psychotherapy improves treatment outcomes for BPD.
Fill in the blank: The distinguishing feature of narcissistic personality disorder compared to histrionic personality disorder is _______.
True or False: Both HPD and NPD lack systematic treatment outcome studies.
Answers: 1. False (BPD shifts happen rapidly, often within hours). 2. Splitting. 3. False. 4. Grandiosity. 5. True.
Q: What are the core features of borderline personality disorder?
A: Emotional dysregulation (out-of-control emotions), hypersensitivity to abandonment, unstable interpersonal relationships (idealising then devaluing), identity disturbance (distorted and unstable self-concept), impulsive self-damaging behaviour, and proneness to transient dissociative states.
Q: Describe how dialectical behaviour therapy (DBT) addresses BPD symptoms.
A: DBT helps clients develop a more realistic and positive sense of self, learn adaptive problem-solving and emotion-regulation skills, correct dichotomous thinking by monitoring and challenging black-and-white evaluations, build assertiveness skills for relationships, and control impulsive behaviours through situational monitoring and alternative responses. Evidence shows it reduces depression, anxiety, and self-mutilation while improving interpersonal functioning.
Q: How do psychoanalytic theories explain the development of BPD?
A: Patients never fully differentiated their view of self from their view of others, making them hypersensitive to others' opinions and abandonment. They are unable to integrate positive and negative qualities of self or others (splitting) because early caregivers rewarded dependence but punished autonomy. This results in instability in emotions and relationships.
Q: Compare histrionic and narcissistic personality disorders.
A: Both involve dramatic behaviour, admiration-seeking, and shallow emotional expression and relationships. HPD centres on attention-seeking and emotional volatility; NPD is distinguished by grandiosity (inflated self-importance, fantasies of power and success, belief in superiority). NPD patients view dependency as weakness, while HPD patients are overly dependent and trusting of authority figures.
Q: What neurobiological differences are associated with BPD?
A: Smaller amygdala and hippocampus volume, greater amygdala activation, and structural and metabolic abnormalities in the prefrontal cortex. These differences may be partly genetic (the disorder runs in families and twin studies show heritability) and partly due to early abuse altering brain development.
BPD connects closely to trauma and PTSD (childhood abuse as a risk factor), emotion regulation (a core deficit in BPD), and attachment theory (insecure attachment patterns underlying psychoanalytic models). NPD connects to social psychology research on self-esteem, self-enhancement, and cultural individualism. All Cluster B disorders connect to the broader discussion of categorical vs. dimensional classification, since these disorders overlap substantially and comorbidity is the norm.
Cluster B, dramatic-emotional, borderline personality disorder, BPD, splitting, emotional dysregulation, dialectical behaviour therapy, DBT, Marsha Linehan, mentalization-based treatment, MBT, transference-focused therapy, TFT, STEPPS, histrionic personality disorder, HPD, attention-seeking, narcissistic personality disorder, NPD, grandiosity, grandiose narcissism, vulnerable narcissism, Pincus and Lukowitzky, amygdala, hippocampus, prefrontal cortex, mood stabilisers, aripiprazole, lamotrigine, olanzapine, psychoanalytic theory, abandonment, identity disturbance, impulsivity, self-harm, comorbidity