[Cerebral insufficiency: differential diagnosis]

Clinicians are mainly concerned with pathological ageing, since any new and unusual neuropsychic manifestation may indicate incipient dementia. In the absence of conclusive clinical or paraclinical criteria, the diagnostic approach consists of excluding other causative factors responsible for similar symptoms and sometimes amenable to treatment. The somatic factors of neurological disorders include in the first place expansive processes, followed by dysthyroidism, anterior pituitary insufficiency, iatrogenic factors and various biochemical disturbances. In the field of psychiatry, depressive states may produce symptoms which only differ from dementia on minor points of semiology. Therapeutic tests with antidepressants should be used when investigating uncommon psychic disorders in elderly patients.