The present work aims to study the psychological manifestations of acute stress occurring in patients hospitalized in the Intensive Care Unit, both from a cognitive, emotional and behavioral point of view, developing a diagnostic and psychological support tool used and tested in the assessment of the dynamics of acute stress disorder, anxiety and depression in patients admitted to intensive care units. Despite the acquisitions in the field of quality of medical services in the Intensive Care Unit the anxiety of patients admitted to this unit, the critical state of patients, fear of medical treatments and specific procedures (which can develop into a pervasive disorder, which adversely affects many areas of individual functioning) involves a procession of cognitive-emotional and behavioural symptoms of varying intensity and frequency, often with an insidious evolution, which affects the patient’s compliance with treatment, and therefore the patient’s health.