[Update on the diagnosis and treatment of delirium].

Delirium is an acute confusional state with typically fluctuating disturbances of attention, cognition, and qualitative awareness. Its incidence depends on the patient group. In the development of delirium, predisposing factors such as age, frailty, multimorbidity, surgical interventions, and pre-existing dementia are of high clinical relevance. The diagnosis of delirium should be based on symptoms and validated screening methods (e.g., Confusion Assessment Method). As delirium is a direct physiological consequence of a medical condition, the potential underlying cause(s) should be diagnosed. Prevention and therapy are primarily multimodal, non-pharmacological treatments such as reorientation, early mobilization, and sleep improvement. If symptomatic pharmacological treatment is necessary (e.g., due to delirium-related agitation), careful drug selection should be made depending on the patient population and symptoms.