Classifying Organic Mental Disorders and Dementia—A Review of Historical Perspectives

Abstract

The concept of dementia should not be used synonymously with the concept of organic mental disorders. By definition, according to DSM-III and ICD-10, dementia is a syndrome which includes memory impairment. The severity of the disorder is disabling and the course is chronic. Differential diagnosis includes age-associated memory impairment (AAMI), delirium, and depressive disorders. The dementias may be subdivided into four groups: idiopathic (primary degenerative dementias), vascular, secondary, and others. The idiopathic dementias are those in which etiology is assumed to be found within the brain itself. The main subgroup is Alzheimer-type dementia. The vascular dementias are those in which the blood supply to the brain is insufficient. Multi-infarct dementia (MID) is the prototype. In secondary dementias, somatic disorders either within or external to the brain cause the dementia.