Delirium, Amnesic Syndromes and Other Cognitive Disorders

This chapter will discuss delirium, amnesic syndromes and other organic mental disorders characterised predominantly by cognitive dysfunction. These disorders are classified within the ICD-10 classification system under organic mental disorders (F0), except where they occur as a consequence of alcohol or substance misuse, in which case they are classified as mental and behavioural disorders due to psychoactive substance use (F1) (World Health Organisation 1992). The DSM-IV classification system uses the term amnestic disorder rather than amnesic syndrome (American Psychiatric Association 1994). Within DSM-IV, delirium, amnestic and other cognitive disorders, including dementia, are grouped within a single section, in which disorders are differentiated on the basis of their aetiology. The causes listed are general medical conditions, effects of a psychotropic substance (alcohol, drugs of abuse and medication side-effects are included under this heading) and multiple aetiologies.