Chapter 14: Anxiety Disorders

Epidemiological data reveal high lifetime prevalence rates, typically early age of onset, and substantial comorbidity with major depression and substance use disorders, underscoring the public health significance of these conditions. The chapter traces diagnostic evolution from historical psychoanalytic conceptualizations through contemporary nosological frameworks including DSM-5-TR and ICD-11 criteria, which emphasize symptom cluster patterns and functional impairment rather than outdated categorical distinctions. Biological mechanisms receive extensive coverage, with particular attention to hypothalamic-pituitary-adrenal axis dysregulation, aberrant GABAergic neurotransmission, serotonergic system dysfunction, genetic predisposition factors, and neuroimaging findings demonstrating amygdala hyperresponsivity to threat stimuli. Psychosocial etiological contributors such as early adverse experiences, personality vulnerability factors, and classical conditioning mechanisms for fear acquisition are integrated into contemporary multifactorial conceptual models. Assessment methodology emphasizes use of standardized psychometric instruments and structured diagnostic interviews to accurately differentiate anxiety disorders from organic medical conditions including thyroid dysfunction, cardiac conduction abnormalities, and respiratory disorders that may mimic anxiety presentations. Comprehensive treatment coverage encompasses pharmacological interventions with selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, benzodiazepines, and azapirone agents alongside evidence-based psychotherapeutic modalities including cognitive-behavioral therapy, systematic desensitization, relaxation techniques, and acceptance-based mindfulness approaches. Special clinical considerations address treatment-resistant presentations, combined therapeutic strategies, and developmentally sensitive applications in pediatric, adolescent, and geriatric populations. The chapter concludes by acknowledging cultural variation in anxiety symptom expression, international epidemiologic patterns, and significant morbidity associated with untreated anxiety disorders.