Lorazepam challenge

The lorazepam challenge is a diagnostic tool used in the clinical diagnosis of catatonia.^[1] Upon treatment with lorazepam, other benzodiazepines, or zolpidem, 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.^[2] Response to lorazepam can support the diagnosis of catatonia and inform treatment strategy, although a minority may not respond to the challenge.^[3] 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.^[4]

Lorazepam is preferred to other benzodiazepines and zolpidem due to its longer duration of action.^[4] An initial therapeutic effect typically occurs within 10–30 minutes of IV administration lorazepam at doses between 2–4 mg.^[5][4] Higher doses may be used in patients who are unresponsive, to minimise the chance of a false negative result.^[4]