CRD summary: This review assessed the efficacy and safety of intramuscular olanzapine in the management of patients with acute agitation. The authors' overall conclusion that further research is required seems appropriate given the differences between the studies identified and the small data set on which the results were based.

CRD commentary: The review question was clear in terms of the study design, intervention, participants and outcomes. Two relevant databases plus references were searched, but no attempts to minimise language or publication bias were made. Two reviewers independently selected studies for inclusion and extracted the data from the primary studies, thus reducing the potential for bias and error.

Although only RCTs were included, the validity assessment was limited and the quality of the included studies was therefore uncertain. Given the differences between the studies with respect to patient characteristics and comparators, the narrative synthesis was appropriate. The authors' conclusions appear appropriate given the evidence presented.