qualitative impairment of consciousness; paroxysmal (suddenly) hallucinatory confusion of consciousness, accompanied by abundant perceptual disorders: illusions, hallucinations of various modalities (visual, verbal, tactile). The leading symptoms are: allopsychic disorientation (disorientation in what is happening around – place, time, situation), detachment, partial amnesia after getting out of the state. Delirium can also be accompanied by pronounced affective disorders (affect of fear, pronounced anxiety, rapid change of emotions), psychomotor disorders (motor restlessness), night sleep disorders (nightmares, insomnia). Delirium is characterized by diurnal fluctuations in severity with worsening at night (undulating course). On average, the duration of delirium is several days (or only nights), but in many respects the course depends on the cause of this condition.