benzodiazepine-induced hallucination

   The benzodiazepines (or 'benzos' for short) are formally known as CNS active 1,4-benzodiazepines. These substances constitute a group of CNS depressants whose major action is attributed to the potentiation of the gamma aminobutyric acid (GABA) system via the benzodiazepine receptors present in the CNS. The name benzodiazepine refers to the benzene and diazepine ring systems constituting the core chemical structure of classic benzodiazepine substances. Some examples of classic benzo-diazepines are chlordiazepoxide, diazepam, lorazepam, and oxazepam. Historically, chlor-diazepoxide was the first of the centrally acting 1,4-benzodiazepine derivatives. It was developed during the 1950s by the group headed by the Polish-Jewish-American chemist Leo Henryk Sternbach (1908-2005), and introduced for clinical use in 1960. Diazepam followed in 1963, with other benzodiazepines patented by Sternbach (and others) following successively. In biomedicine the benzodiazepines are prescribed for a wide variety of purposes, including the treatment of insomnia, epileptic seizures, anxiety, depression, agitation, aggression, and acute alcohol withdrawal. Because of their sedative and anxiolytic properties, the benzodiazepines are also widely misused. Their consumption may lead to dependency, as well as to a multitude of adverse effects. * Nightmares and vivid * dreaming have been reported during benzodiazepine use, as well as alterations in the qualitative character of dream images. Reports of benzodiazepine-induced hallucinations are less common. In 1968 the American psychiatrist Davis S. Viscott published a report on seven cases of apparent hallucinatory activity following the first-time use of chlordiazepoxide. However, it is unclear from Viscott's report whether the hallucinatory phenomena at hand were de novo hallucinations, or pre-existent hallucinations which the affected individuals had apparently never talked about until they came to do so under the influence of chlordiazepoxide. Benzodiazepine withdrawal, on the other hand, is notorious for its many perceptual rebound effects. These include * sensory deceptions and distortions such as * hyperaesthesia, * metamorphopsias, *visual hallucinations, * auditory hallucinations, *formication, and * body schema illusions. Although the effects of benzodiazepine use in individuals with a clinical diagnosis of *schizophrenia have been studied extensively throughout the years, its influence upon hallucinations and other psychotic symptoms remains somewhat unclear. Some studies indicate that the benzodiazepines may have a potentiating effect on antipsychotic substances, while others fail to record such an effect, or even report a decrease in the effectiveness of antipsychotic agents under benzodiazepine co-medication.

   References

   Costa, E., ed. (1983). The benzodiazepines. From molecular biology to clinical practice.New York, NY: Raven.

   Viscott, D.S. (1968). Chlordiazepoxide and hallucinations. Archives ofGeneral Psychiatry, 19, 370-376.