Clinical meaning
Personality disorders (PDs) are enduring patterns of inner experience and behavior that deviate markedly from cultural expectations, are pervasive and inflexible, begin in adolescence or early adulthood, are stable over time, and lead to distress or functional impairment. They are organized into three clusters. Cluster A (odd/eccentric): paranoid PD (pervasive distrust and suspiciousness), schizoid PD (detachment from social relationships, restricted emotions), schizotypal PD (eccentric behavior, cognitive/perceptual distortions, magical thinking). Cluster B (dramatic/erratic): borderline PD (instability in relationships, self-image, and affect; impulsivity; self-harm; fear of abandonment), antisocial PD (disregard for rights of others, deceit, manipulation, lack of remorse), histrionic PD (excessive emotionality and attention-seeking), narcissistic PD (grandiosity, need for admiration, lack of empathy). Cluster C (anxious/fearful): avoidant PD (social inhibition, feelings of inadequacy, hypersensitivity to criticism), dependent PD (excessive need to be taken care of, submissive behavior), obsessive-compulsive PD (preoccupation with orderliness, perfectionism, control -- distinct from OCD). Borderline PD (BPD) is the most commonly encountered in clinical settings and has the most evidence-based treatments. BPD pathophysiology involves amygdala hyperreactivity (intense emotional responses to perceived threats), prefrontal cortex hypoactivity (impaired emotion...