Fundamentals of Psychological Disorders

Fundamentals of Psychological Disorders (formerly titled Abnormal Psychology) is a comprehensive open textbook created by Dr. Alexis Bridley and Dr. Lee W. Daffin Jr. through Washington State University. Updated through the DSM-5-TR diagnostic criteria, the book explores the complex field of psychopathology across 16 modular units. The text begins by establishing foundational concepts, examining the definition of abnormal behavior, theoretical models of psychopathology, and clinical assessment, diagnosis, and treatment planning methods. Subsequent modules systematically cover major diagnostic classes across five organized blocks: mood, trauma-, stressor-related, and dissociative disorders; anxiety, somatic symptom, and obsessive-compulsive disorders; eating and substance-related disorders; schizophrenia spectrum and personality disorders; and neurocognitive, childhood, and contemporary psychopathological issues. Each disorder class is analyzed through a standardized pedagogical framework covering clinical presentation, official DSM criteria, epidemiology, comorbidity, multidimensional etiology, and evidence-based treatment options. Designed for undergraduate psychology, mental health, and behavioral science courses, this open textbook provides an accessible, rigorous instructional foundation that can be easily adopted, customized, or integrated into institutional learning management systems.