Benzodiazepines for psychosis-induced aggression or agitation

Acute psychotic illness, especially when associated with agitated or violent behaviour, can require urgent pharmacological tranquillisation or sedation. In several countries, clinicians often use benzodiazepines (either alone or in combination with antipsychotics) for this outcome.

To examine whether benzodiazepines, alone or in combination with other pharmacological agents, is an effective treatment for psychosis-induced aggression or agitation when compared with placebo, other pharmacological agents (alone or in combination) or non-pharmacological approaches.

We searched the Cochrane Schizophrenia Group's register (January 2012, 20 August 2015 and 3 August 2016), inspected reference lists of included and excluded studies, and contacted authors of relevant studies.

We included all randomised controlled trials (RCTs) comparing benzodiazepines alone or in combination with any antipsychotics, versus antipsychotics alone or in combination with any other antipsychotics, benzodiazepines or antihistamines, for people who were aggressive or agitated due to psychosis.

We reliably selected studies, quality assessed them and extracted data. For binary outcomes, we calculated standard estimates of risk ratio (RR) and their 95% confidence intervals (CI) using a fixed-effect model. For continuous outcomes, we calculated the mean difference (MD) between groups. If there was heterogeneity, this was explored using a random-effects model. We assessed risk of bias and created a 'Summary of findings' table using GRADE.

Twenty trials including 695 participants are now included in the review. The trials compared benzodiazepines or benzodiazepines plus an antipsychotic with placebo, antipsychotics, antihistamines, or a combination of these. The quality of evidence for the main outcomes was low or very low due to very small sample size of included studies and serious risk of bias (randomisation, allocation concealment and blinding were not well conducted in the included trials, 30% of trials (six out of 20) were supported by pharmaceutical institutes). There was no clear effect for most outcomes.Benzodiazepines versus placeboOne trial compared benzodiazepines with placebo. There was no difference in the number of participants sedated at 24 hours (very low quality evidence). However, for the outcome of global state, clearly more people receiving placebo showed no improvement in the medium term (one to 48 hours) (n = 102, 1 RCT, RR 0.62, 95% CI 0.40 to 0.97, very low quality evidence). Benzodiazepines versus antipsychoticsWhen compared with haloperidol, there was no observed effect for benzodiazepines for sedation by 16 hours (n = 434, 8 RCTs, RR 1.13, 95% CI 0.83 to 1.54, low quality evidence). There was no difference in the number of participants who had not improved in the medium term (n = 188, 5 RCTs, RR 0.89, 95% CI 0.71 to 1.11, low quality evidence). However, one small study found fewer participants improved when receiving benzodiazepines compared with olanzapine (n = 150, 1 RCT, RR 1.84, 95% CI 1.06 to 3.18, very low quality evidence). People receiving benzodiazepines were less likely to experience extrapyramidal effects in the medium term compared to people receiving haloperidol (n = 233, 6 RCTs, RR 0.13, 95% CI 0.04 to 0.41, low quality evidence).Benzodiazepines versus combined antipsychotics/antihistaminesWhen benzodiazepine was compared with combined antipsychotics/antihistamines (haloperidol plus promethazine), there was a higher risk of no improvement in people receiving benzodiazepines in the medium term (n = 200, 1 RCT, RR 2.17, 95% CI 1.16 to 4.05, low quality evidence). However, for sedation, the results were controversial between two groups: lorazepam may lead to lower risk of sedation than combined antipsychotics/antihistamines (n = 200, 1 RCT, RR 0.91, 95% CI 0.84 to 0.98, low quality evidence); while, midazolam may lead to higher risk of sedation than combined antipsychotics/antihistamines (n = 200, 1 RCT, RR 1.13, 95% CI 1.04 to 1.23, low quality evidence).Other combinationsData comparing benzodiazepines plus antipsychotics versus benzodiazepines alone did not yield any results with clear differences; all were very low quality evidence. When comparing combined benzodiazepines/antipsychotics (all studies compared haloperidol) with the same antipsychotics alone (haloperidol), there was no difference between groups in improvement in the medium term (n = 185, 4 RCTs, RR 1.17, 95% CI 0.93 to 1.46, low quality evidence), but sedation was more likely in people who received the combination therapy (n = 172, 3 RCTs, RR 1.75, 95% CI 1.14 to 2.67,very low quality evidence). Only one study compared combined benzodiazepine/antipsychotics with antipsychotics; however, this study did not report our primary outcomes. One small study compared combined benzodiazepines/antipsychotics with combined antihistamines/antipsychotics. Results showed a higher risk of no clinical improvement (n = 60, 1 RCT, RR 25.00, 95% CI 1.55 to 403.99, very low quality evidence) and sedation status (n = 60, 1 RCT, RR 12.00, 95% CI 1.66 to 86.59, very low quality evidence) in the combined benzodiazepines/antipsychotics group.

The evidence from RCTs for the use of benzodiazepines alone is not good. There were relatively few good data. Most trials were too small to highlight differences in either positive or negative effects. Adding a benzodiazepine to other drugs does not seem to confer clear advantage and has potential for adding unnecessary adverse effects. Sole use of older antipsychotics unaccompanied by anticholinergic drugs seems difficult to justify. Much more high-quality research is still needed in this area.