Abnormal behavior, often referred to as mental illness, results from changes in brain function that influence thought patterns, behaviors, and social interactions. Psychologists and psychiatrists typically assess abnormal behavior using three primary criteria: deviance, maladaptation, and personal distress, particularly when these traits persist over long periods.
Deviant Behavior
Deviance in behavior refers to actions or thought patterns that significantly diverge from societal norms or...

Antisocial personality disorder is a chronic mental health condition characterized by persistent patterns of disregard for the rights and well-being of others. Individuals with antisocial personality disorder exhibit behaviors that include deceitfulness, impulsivity, irresponsibility, aggression, and a profound lack of empathy. These traits often manifest early in life and persist into adulthood, leading to significant personal, social, and legal consequences.
Behavioral Characteristics and...

Conduct disorder is a complex mental health diagnosis characterized by a repetitive and persistent pattern of behavior that violates societal norms, the rights of others, or age-appropriate rules. The diagnostic criteria for conduct disorder require the presence of at least three problematic behaviors within the past 12 months, with at least one occurring in the past six months. These behaviors are grouped into four categories: aggression toward people and animals; destruction of property;...

The Diagnostic and Statistical Manual of Mental Disorders (DSM) serves as the primary classification system for mental health disorders, providing standardized diagnostic criteria for clinicians and researchers. First published by the American Psychiatric Association (APA) in 1952, the DSM has undergone several revisions to reflect evolving psychiatric understanding. The fifth edition, DSM-5, released in 2013, introduced key updates that expanded diagnostic categories and modified diagnostic...

The development of psychological disorders, which are characterized by deviant, maladaptive, and personally distressing behaviors, has been explored through several theoretical approaches.
Biological approach
The biological approach posits that internal, organic factors are the primary causes of such disorders. This perspective emphasizes brain structure and function, genetic predispositions, and neurotransmitter imbalances. For example, schizophrenia has been associated with both genetic...

Borderline Personality Disorder is a complex and multifaceted mental health condition characterized by pervasive instability in interpersonal relationships, self-image, emotions, and impulse control. This instability manifests in extreme emotional reactions, fear of abandonment, and self-destructive behaviors. The disorder significantly impacts daily functioning, often leading to distress in both personal and professional domains.
Genetic and Environmental Contributions
Borderline Personality...