A personality disorder is a type of mental health condition that affects how a person thinks, feels, and behaves. Individuals with these disorders often have rigid and unhealthy patterns of thinking and functioning, which can lead to difficulties in relationships and daily life. Common types include borderline personality disorder, narcissistic personality disorder, and antisocial personality disorder. These disorders typically emerge in adolescence or early adulthood and can vary in severity. Treatment often involves therapy, such as cognitive-behavioral therapy, to help individuals understand and change their thought patterns and behaviors. In some cases, medication may also be prescribed to manage symptoms.