This review considers the issues of clinical typology of delirium (mental confusion), its etiology and pathogenesis. Based on these data, the peculiarities of treatment, prevention and rehabilitation of delirium are discussed. Attention is drawn to the risk factors of this disorder (potentially modifiable or non-modifiable), which are most important in treatment and prevention of delirium. The questions of rehabilitation measures are regarded. Section "Treatment" presents pharmacological and non-pharmacological approaches to treatment of delirium.