Edoardo G Ostinelli, Salwan Jajawi, Styliani Spyridi, Kamlaj Sayal, Mahesh B Jayaram

People experiencing psychosis may become aggressive. Antipsychotics, such as aripiprazole in intramuscular form, can be used in such situations. To evaluate the effects of intramuscular aripiprazole in the treatment of psychosis-induced aggression or agitation (rapid tranquillisation). On 11 December 2014 and 11 April 2017, we searched the Cochrane Schizophrenia Group's Study-based Register of Trials which is based on regular searches of CINAHL, BIOSIS, AMED, Embase, PubMed, MEDLINE, PsycINFO, and registries of clinical trials. All randomised controlled trials (RCTs) that randomised people with psychosis-induced aggression or agitation to receive either intramuscular aripiprazole or another intramuscular intervention. We independently inspected citations and, where possible, abstracts, ordered papers and re-inspected and quality assessed these. We included studies that met our selection criteria. At least two review authors independently extracted data from the included studies. We chose a fixed-effect model. We analysed dichotomous data using risk ratio (RR) and the 95% confidence intervals (CI). We analysed continuous data using mean differences (MD) and their CIs. We assessed risk of bias for included studies and used GRADE to create 'Summary of findings' tables. Searching found 63 records referring to 21 possible trials. We could only include three studies, all completed over the last decade, with 885 participants, of which 707 were included for quantitative analyses in this systematic review. Due to limited comparisons, small size of trials and a paucity of investigated and reported 'pragmatic' outcomes, evidence was mostly graded as low or very low quality. No trials reported useful data for one of our primary outcomes of tranquil or asleep by 30 minutes. Economic outcomes were also not reported in the trials.When compared with placebo, fewer people in the aripiprazole group needed additional injections compared to the placebo group (2 RCTs, n = 382, RR 0.69, 95% CI 0.56 to 0.85, very low-quality evidence). Clinically important improvement in agitation at two hours favoured the aripiprazole group (2 RCTs, n = 382, RR 1.50, 95% CI 1.17 to 1.92, very low-quality evidence). The numbers of non-responders after the first injection also favoured aripiprazole (1 RCT, n = 263, RR 0.49, 95% CI 0.34 to 0.71, low-quality evidence). Although no effect was found, more people in the aripiprazole compared to the placebo group experienced adverse effects (1 RCT, n = 117, RR 1.51, 95% CI 0.93 to 2.46, very low-quality evidence).Aripiprazole required more injections compared to haloperidol (2 RCTs, n = 477, RR 1.28, 95% CI 1.00 to 1.63, very low-quality evidence), with no significant difference in agitation (2 RCTs, n = 477, RR 0.94, 95% CI 0.80 to 1.11, very low-quality evidence), and similar non-responders after first injection (1 RCT, n = 360, RR 1.18, 95% CI 0.78 to 1.79, low-quality evidence). Aripiprazole and haloperidol did not differ when taking into account the overall number of people that experienced at least one adverse effect (1 RCT, n = 113, RR 0.91, 95% CI 0.61 to 1.35, very low-quality evidence).Compared to aripiprazole, olanzapine was better at reducing agitation (1 RCT, n = 80, RR 0.77, 95% CI 0.60 to 0.99, low-quality evidence) and had a more favourable effect on global state change scores (1 RCT, n = 80, MD 0.58, 95% CI 0.01 to 1.15, low-quality evidence), both at two hours. No differences were found in terms of experiencing at least one adverse effect during the 24 hours after treatment (1 RCT, n = 80, RR 0.75, 95% CI 0.45 to 1.24, very low-quality evidence). However, participants allocated to aripiprazole experienced less somnolence (1 RCT, n = 80, RR 0.25, 95% CI 0.08 to 0.82, low-quality evidence). The available evidence is of poor quality but there is some evidence aripiprazole is effective compared to placebo and haloperidol, but not when compared to olanzapine. However, considering that evidence comes from only three studies, caution is required in generalising these results to real-world practice. This review firmly highlights the need for more high-quality trials on intramuscular aripiprazole in the management of people with acute aggression or agitation.