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