The lorazepam challenge is a diagnostic tool used in the clinical diagnosis of

catatonia Catatonia is a complex syndrome most commonly seen in people with underlying mood disorders, such as major depressive disorder, or psychotic disorders, such as schizophrenia. People with catatonia exhibit abnormal movement and behaviors, wh ...

. Upon treatment with

lorazepam Lorazepam, sold under the brand name Ativan, Tavor among others, is a benzodiazepine medication. It is used to treat anxiety (including anxiety disorders), insomnia, severe agitation, active seizures including status epilepticus, alcoh ...

, other

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant, depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed t ...

s, or

zolpidem Zolpidem, sold under the brand name Ambien among others, is a medication primarily used for the short-term treatment of sleeping problems. Guidelines recommend that it be used only after cognitive behavioral therapy for insomnia and after beh ...

, a rapid reversal of the catatonic state is often observed in catatonic patients. A positive response is usually defined as a 50% reduction in catatonic symptoms using a standardized scale. Response to lorazepam can support the diagnosis of catatonia and inform treatment strategy, although a minority may not respond to the challenge. The lorazepam challenge can elicit a false positive result when administered to patients afflicted with conditions that can sometimes mimic catatonia, such as benzodiazepine and alcohol withdrawal. Lorazepam is preferred to other benzodiazepines and zolpidem due to its longer duration of action. An initial therapeutic effect typically occurs within 10–30 minutes of IV administration lorazepam at doses between 2–4 mg. Higher doses may be used in patients who are unresponsive, to minimise the chance of a false negative result.

Mechanism of action

The mechanism underlying rapid response to benzodiazepines and zolpidem in catatonia is unknown. The observation that zolpidem, a selective hypnosedative with little to no muscle relaxing properties, elicits a challenge response similar to benzodiazepines has called into question the hypothesis that lorazepam may reverse catatonia through myorelaxation.

References

{{reflist Catatonia