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...

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...

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...

Panic disorder is an anxiety disorder characterized by recurrent and sudden minutes-long episodes of intense fear, known as panic attacks. These attacks may feel like heart attacks and often happen without warning or a specific cause. They can include symptoms such as rapid heart rate, shortness of breath, chest pain, trembling, sweating, dizziness, and a sense of helplessness. During a panic attack, individuals may feel as though they are experiencing a heart attack or are in a...

Obsessive-compulsive disorder (OCD) is a mental health condition characterized by recurrent obsessions, compulsions, or both, which consume significant time and interfere with daily functioning. Obsessions involve persistent, intrusive, and unwanted thoughts, images, or urges that evoke anxiety. Common examples include irrational fears of contamination or harm. Compulsions are repetitive behaviors or mental acts performed to reduce the anxiety caused by obsessions. For instance, individuals...

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...