Abstract: The 2011 update search yielded three further randomised controlled trials. The review currently includes 34 studies with 2657 participants. Most studies were characterised by a small sample size, short duration, and incomplete outcome data reporting. Benzodiazepine monotherapy is compared with placebo in eight trials. The proportion of participants with no clinically important response did not significantly differ between those given benzodiazepines or placebo (N = 382, 6 RCTs, RR 0.67 CI 0.44 to 1.02). The results from the various rating scales applied to assess global and mental state were inconsistent. Fourteen studies examined benzodiazepine monotherapy in comparison with antipsychotic monotherapy. Clinically important treatment response assessment revealed no statistically significant difference between the study groups (30 minutes: N = 44, 1 RCT, RR 0.91 CI 0.58 to 1.43; 60 minutes: N = 44,1 RCT, RR 0.61 CI 0.20 to 1.86; 12 hours: N = 66, 1 RCT, RR 0.75 CI 0.44 to 1.30; pooled short-term studies: N = 112, 2 RCTs, RR 1.48 CI 0.64 to 3.46). Desired sedation occurred significantly more often among participants in the benzodiazepine group than in the antipsychotic group at 20 and 40 minutes. No significant between-group differences could be identified for global and mental state or occurrence of adverse effects. Twenty trials compared benzodiazepine augmentation of antipsychotics with antipsychotic monotherapy. Referring to clinically important response, statistically significant improvement could be demonstrated only for the first 30 minutes of augmentation treatment (30 minutes: 1 RCT, N = 45, RR 0.38 CI 0.18 to 0.80; 60 minutes: N = 45,1 RCT, RR 0.07 CI 0.00 to 1.13; 12 hour: N = 67,1 RCT, RR 0.85 CI 0.51 to 1.41; pooled short-term studies: N = 511, 6 RCTs, RR 0.87 CI 0.49 to 1.54). Analyses of the global and mental state yielded no between-group differences except for desired sedation at 30 as well as 60 minutes (30 minutes: N = 45, 1 RCT, RR 2.25 CI 1.18 to 4.30; 60 minutes: N = 45, 1 RCT, RR 1.39 CI 1.06 to 1.83). There is currently no convincing evidence to confirm or refute the practise of administering benzodiazepines as monotherapy or in combination with antipsychotics for the pharmacological treatment of schizophrenia and schizophrenia-like psychosis. Low-quality evidence suggests that benzodiazepines are effective for very short-term sedation and could be considered for calming acutely agitated people with schizophrenia. Measured by the overall attrition rate, the acceptability of benzodiazepine treatment appears to be adequate. Adverse effects were generally poorly reported. High-quality future research projects with large sample sizes are required to clarify the evidence of benzodiazepine treatment in schizophrenia, especially regarding long-term augmentation strategies.

Plain-language summary: This review found 34 studies with 2657 people. It compared benzodiazepines when used alone as the only medication or when used in combination with another drug for people with schizophrenia. Information from the 34 studies was generally poor, incomplete and badly reported. The 34 studies were of short duration and were small in size. The review suggests that there is little evidence to support the use of benzodiazepines either alone or in combination. However, benzodiazepines do have sedative properties that can calm people down and help them become less agitated for short periods of time. More research, particularly involving benzodiazepines as add-on treatment used in combination with traditional antipsychotic drugs, is required. This plain language summary has been written by Benjamin Gray, Service User and Service User Expert, Rethink Mental Illness, Email: [email protected]