Cluster A disorders are marked by social isolation and difficulties in forming and maintaining interpersonal relationships. Features of these disorders include odd, unconventional, idiosyncratic, and unusual beliefs/thought patterns, behaviors, and difficulties in social interactions. As these disorders can make social interactions challenging, treatment can involve therapy to address social and interpersonal difficulties and improve overall functioning.

Disorders in this category include the following:

Paranoid Personality Disorder (PPD)
This disorder is characterized by a pervasive pattern of distrust and suspiciousness of others, such that motives are interpreted as malevolent. Individuals may be reluctant to confide in others, hold grudges, and frequently question the loyalty of their associates related to beliefs or fears of exploitation, harm, or deception without sufficient basis.

Schizoid Personality Disorder (SPD)
SPD is characterized by a pervasive pattern of detachment from social relationships and a restricted range of emotional expression in interpersonal settings. Individuals with SPD often prefer solitary activities and takes pleasure in few, if any, activities. They lack a desire for close relationships, have limited emotional expression.

Schizotypal Personality Disorder (STPD)
This disorder is characterized by a pervasive pattern of social and interpersonal deficits marked by acute discomfort with, and reduced capacity for, close relationships. Individuals with STPD exhibit odd beliefs, eccentric behavior, and cognitive or perceptual distortions (e.g., ideas of reference, unusual/odd beliefs or magical thinking).

Cluster B disorders are associated with difficulties in impulse control, emotional regulation, and maintaining stable relationships. Individuals with these disorders may exhibit intense, dramatic, erratic emotions and behaviors contributing to difficulties in regulating emotions and forming stable interpersonal relationships. Treatment often involves psychotherapy to address the underlying emotional and interpersonal issues associated with these disorders.

Disorders in this category include the following:

Antisocial Personality Disorder (ASPD)
Individuals with ASPD often display a disregard for the rights of others, a lack of empathy, and a history of behavior that violates societal norms and rules. This pervasive pattern is often prevalent before the age of 15, as indicated by the prevalence of Conduct Disorder. As adults, this disorder manifests through deceitfulness, impulsivity, irresponsibility, irritability and aggression, and a lack of remorse. *This disorder is not “antisocial” in the sense of asocial, introversion, social isolation or discomfort.

Borderline Personality Disorder (BPD)
BPD is marked by a pervasive pattern of instability in interpersonal relationships, self-image, and affect (mood and regulation), as well as marked impulsivity. People with BPD often experience intense mood swings, fear of abandonment, and identity disturbance. They make frantic efforts to avoid real or imagined abandonment and may engage recurrent self-injurious behavior that is distinctly different than self-harm or self-injury motivated by suicidal idealization (e.g., cutting absent of intent to die).

Histrionic Personality Disorder (HPD)
HPD is categorized by a pervasive pattern of excessive emotionality and attention-seeking behavior. Individuals with HPD exhibit a strong need to be the center of attention and tend to feel extreme discomfort in situations where they are not the center of attention. They may also displays shallow and rapidly shifting emotions.

Narcissistic Personality Disorder (NPD)
NPD is pervasive pattern of grandiosity (in fantasy or behavior), need for admiration, and lack of empathy. The individual has a grandiose sense of self-importance, a preoccupation with fantasies of unlimited success, and a belief in their special uniqueness.

Cluster C disorders are characterized by anxious, fearful, or avoidant behaviors and thought patterns. The high levels of anxiety and fear can significantly impact an individual's daily functioning and interpersonal relationships. Treatment typically involves psychotherapy and, in some cases, medication to address associated symptoms like anxiety or depression.

Disorders in this category include the following:

Avoidant Personality Disorder (AvPD)
Individuals with AvPD exhibit extreme social inhibition, intense feelings of inadequacy, and a strong fear of rejection and criticism. They often avoid social interactions and new situations due to their fear of negative evaluation.

Dependent Personality Disorder (DPD)
People with DPD display an excessive need to be taken care of, often leading to submissive and clingy behavior. They have difficulty making decisions independently and rely heavily on others for emotional and practical support.

Obsessive-Compulsive Personality Disorder (OCPD)
OCPD is different from Obsessive-Compulsive Disorder (OCD). Individuals with OCPD are preoccupied with perfectionism, orderliness, and control. They often set excessively high standards for themselves and others and may be rigid in their behaviors and beliefs.