Chapter 46: Treatment of Personality Disorders

Personality disorders are cataloged across ten subtypes in the DSM-IV and ICD-10 systems, organized into three distinct clusters (A: Odd/Eccentric, B: Dramatic/Erratic, C: Anxious/Fearful); however, the categorical, medical model approach used by these systems is widely considered inadequate, as empirical evidence does not strongly support the qualitative distinctness or fixed thresholds between diagnoses, leading many experts to favor dimensional conceptualizations. The clinical landscape is further complicated by pervasive co-morbidity, meaning patients often meet criteria for multiple PD subtypes, as well as high rates of co-occurring Axis I disorders (such as depression or substance misuse), which often severely limits the effectiveness of traditional treatments and has historically fueled therapeutic pessimism. Given the long-standing, inflexible, and interpersonal nature of PDs, individuals frequently utilize extensive services but exhibit high drop-out rates, struggling to maintain the "patient role" due to mistrust of figures in authority. Effective intervention requires treatments specifically tailored to personality pathology, drawing on three main theoretical foundations: the medical, psychoanalytic, and cognitive-behavioral models. Pharmacological approaches, which aim to manage symptoms based on overlap with Axis I disorders, have consistently shown inadequate evidence of effectiveness. Psychological treatments, which conceptualize PD etiology in terms of distorted schemas, core beliefs, and ways of relating learned from childhood environments, are more promising. Key psychological interventions include Cognitive-Behavioral Therapy (CBT), modified to target fundamental views of self and others and address the complex therapist-client relationship; Dialectical Behavior Therapy (DBT), developed specifically for Borderline Personality Disorder (BPD), which uses a biosocial model and combines individual therapy, skills groups, and crisis phone coaching to synthesize acceptance and change; object-relations psychoanalytic theory, which views BPD as a failure to integrate good and bad aspects of self and others (splitting); and Mentalization-Based Treatment (MBT), which focuses on restoring the capacity to understand self and others in terms of intentional mental states. Additionally, Democratic Therapeutic Communities (DTCs) foster responsibility and behavioral change through communalism, democratization, permissiveness, and reality confrontation in a long-term group setting. Although preliminary evidence suggests specialist treatments are more effective than treatment as usual, the lack of consensus on outcome measures and scarcity of randomized controlled trials mean no single approach is yet proven to be the definitive treatment of choice.