delirium

delirium is a widely-used diagnostic category used to denote a confused and excited state. It has been recognized ever since antiquity. Plato stated that there were four kinds of delirium; that of the prophets sent by Apollo, that of the ‘initiated’ sent by Dionysus, that of the poets due to the Muses, and that of lovers caused by Aphrodite and Eros.

The core symptoms are disturbances of consciousness accompanied by a change in cognition. The disturbance develops over a period of hours or days, and tends to fluctuate. A patient may be coherent and co-operative in the morning but at night insist on leaving hospital and going home to long-dead parents. Maniacal excitement often sets in, sometimes accompanied by violence. Other physical manifestations include muscular tremors and sweats.

The disturbance in consciousness is marked by a muddled awareness. Attention is impaired, and a delirious person is difficult to engage in conversation and easily distracted by irrelevant stimuli. There is an accompanying change in cognition — memory impairment, disorientation, or language disturbance — and sometimes the emergence of perceptual disturbance, usually manifested in disorientation with respect to time or place. In some cases, speech is rambling or incoherent. Language disturbance may be evident, as in dysnomia (impaired ability to name objects) or dysgraphia (reduced ability to write). Perceptual disturbances are common. A banging door may be mistaken for a gunshot (misinterpretation); bedclothes may turn into terrifying animals (illusion); or the person may ‘see’ enemies when no one is actually there (hallucination).

The debates over delirium as a diagnostic label concern its relationship to mental disease and, hence, more broadly, to the mind-body problem. Until the nineteenth century, disorientation with memory loss, and loss of the sense of time and place, was routinely considered a sign of mental disease. Since then, it has become accepted that many types of mental disorder occur without delirium (manie sans délire in the formulation developed by Pinel and Esquirol in France). There has, by consequence, been a growing tendency to stress the organic aetiology of delirium.

In modern medical thinking it is axiomatic that delirium is primarily an organic condition. From the patient's history, physical examination, or laboratory tests it will be apparent whether it arises as a physiological consequence of some medical condition (e.g. fever), or through injury to the head, or through substance intoxication or withdrawal, or through use of a medication (for instance, bromides or barbiturates), or by exposure to poison.

Substance-induced delirium has achieved considerable prominence nowadays. This includes the diagnosis of delirium tremens — a state of confusion, agitation, and tremulousness, associated with alcohol or its withdrawal, first identified as a separate clinical entity in 1813 by Thomas Sutton, who coined the term. Alcoholic delirium is a product not merely of excessive alcohol consumption but of accompanying exhaustion, lack of food, and dehydration. The patient has usually been deteriorating physically because of vomiting and restlessness. Vitamin B deficiency is also implicated.

Roy Porter

Bibliography

Berrios, G. E. (1996). The history of mental symptoms: descriptive psychopathology since the nineteenth century. Cambridge University Press.

See also mind–body problem; psychological disorders.