Delirium in Older Adults: Pathophysiological Mechanisms and Current Pharmacological Approaches

Delirium is an acute neuropsychiatric syndrome characterized by a sudden and transient alteration in the state of consciousness, accompanied by global impairment of cognitive functions.It is a complex condition, with clinical manifestations ranging from difficulty maintaining attention to alterations in memory, language and perception.The clinical picture can vary widely, with fluctuations in the level of consciousness throughout the day, alternating between periods of drowsiness, restlessness and psychomotor agitation.These fluctuations make it difficult for the patient to interact with the environment and often confuse the diagnosis, especially in individuals with other neurological or psychiatric conditions.One of the most striking features of delirium is the alteration of the sleep-wake cycle, which often manifests itself as insomnia at night and excessive sleepiness during the day, and there can also be a complete reversal of these patterns.The fluctuation of symptoms, with worsening at night -a phenomenon known as "twilight" -is one of the clinical aspects that help differentiate delirium from other conditions, such as dementia, which has a more insidious and continuous evolution.This temporal variability of symptoms reinforces the importance of careful and repeated clinical assessment throughout the day, especially in at-risk populations.Delirium is particularly common in hospital environments, with a higher prevalence among the elderly and patients in intensive care units.Studies indicate that its occurrence can vary between 10% and 80%, depending on the population assessed and the criteria used for diagnosis.This high prevalence, coupled with the negative impact on clinical outcomes -such as increased morbidity and mortality, longer hospital stays and the risk of institutionalizationhighlights the need for effective strategies for its early identification and appropriate management.Continuing education for healthcare teams, combined with systematic assessment the condition, making early diagnosis difficult.