The document discusses adjustment disorder, including its definition as a stress-related symptom complex occurring within 3 months of a stressor. It outlines the evolution of the diagnosis from the 11th century to DSM-5 and reviews epidemiology, diagnostic guidelines, clinical presentation, course/prognosis, management, and challenges regarding the diagnosis. While criticized as vague, adjustment disorder remains one of the most commonly diagnosed disorders, especially in consultation-liaison settings. Improving operationalization of the diagnosis is needed to address its shortcomings.