Organic brain syndromes from a psychiatric point of view: diagnostic and nosological aspects.

Organic brain syndromes constitute increasing public health, social and economic problems. In the diagnosis of organic brain syndrome no single symptom is pathognomonic. The core features of organic brain syndrome are disturbances in cognitive functions (memory, thinking, perception, and attention). The expression of emotions is altered, and alertness and vigilance are disturbed. The clinical picture is confused by compensatory, protective, and reactive symptoms. The most important psychopathogenetic mechanisms of organic brain syndrome are impaired cerebral function and the subjective meaning of the illness to the individual. According to American Psychiatric Association's classification (DSM-III), organic brain syndromes can be divided into seven purely descriptive clusters; subdivisions into psychotic and nonpsychotic syndromes and into acute and chronic brain syndromes have been omitted. The organic brain syndromes are delirium, dementia, amnestic syndrome, organic delusional syndrome, organic hallucinosis, organic affective syndrome and organic personality syndrome. The differential diagnostic aspects are discussed. Organic brain syndromes caused by industrial chemicals are nonspecific and multifactorial. When long term exposure to organic solvents occurs, the clinical picture is often characterized by tiredness and astheno-emotional or neurasthenic syndrome resembling neurotic states, depressive states, or presenile dementia.