Abstract: The review currently includes 15 randomised controlled trials with 626 participants. No trials compared flupenthixol decanoate with placebo. One small study compared flupenthixol decanoate with an oral antipsychotic (penfluridol). Only two outcomes were reported with this single study, and it demonstrated no clear differences between the two preparations as regards leaving the study early (n = 60, 1 RCT, RR 3.00, CI 0.33 to 27.23,very low quality evidence) and requiring anticholinergic medication (1 RCT, n = 60, RR 1.19, CI 0.77 to 1.83, very low quality evidence). Ten studies in total compared flupenthixol decanoate with other depot preparations, though not all studies reported on all outcomes of interest. There were no significant differences between depots for outcomes such as relapse at medium term (n = 221, 5 RCTs, RR 1.30, CI 0.87 to 1.93, low quality evidence), and no clinical improvement at short term (n = 36, 1 RCT, RR 0.67, CI 0.36 to 1.23, low quality evidence). There was no difference in numbers of participants leaving the study early at short/medium term (n = 161, 4 RCTs, RR 1.23, CI 0.76 to 1.99, low quality evidence) nor with numbers of people requiring anticholinergic medication at short/medium term (n = 102, 3 RCTs, RR 1.38, CI 0.75 to 2.25, low quality evidence). Three studies in total compared high doses (100 to 200 mg) of flupenthixol decanoate with the standard doses (˜40mg) per injection. Two trials found relapse at medium term (n = 18, 1 RCT, RR 1.00, CI 0.27 to 3.69, low quality evidence) to be similar between the groups. However people receiving a high dose had slightly more favourable medium term mental state results on the Brief Psychiatric Rating Scale (BPRS) (n = 18, 1 RCT, MD -10.44, CI -18.70 to -2.18, low quality evidence). There was also no significant difference in the use of anticholinergic medications to deal with side effects at short term (2 RCTs n = 47, RR 1.12, CI 0.83 to 1.52 very low quality evidence). One trial comparing a very low dose of flupenthixol decanoate (˜6 mg) with a low dose (˜9 mg) per injection reported no difference in relapse rates (n = 59, 1 RCT, RR 0.34, CI 0.10 to 1.15, low quality evidence). In the current state of evidence, there is nothing to choose between flupenthixol decanoate and other depot antipsychotics. From the data reported in clinical trials, it would be understandable to offer standard dose rather than the high dose depot flupenthixol as there is no difference in relapse. However, data reported are of low or very low quality and this review highlights the need for large, well-designed and reported randomised clinical trials to address the effects of flupenthixol decanoate.

Plain-language summary: This review looks at the effectiveness of depot flupenthixol decanoate in comparison with no active treatment (placebo), oral antipsychotics and other depot preparations for people with schizophrenia and other severe mental illnesses. An electronic search for relevant trials was carried out in 2013. Fifteen trials with 626 participants could be included. All evidence from these trials was rated by the authors to be low or very low quality. Currently, from the data reported, there is nothing to choose between depot flupenthixol decanoate and other depot or oral antipsychotics. There was some evidence that it would be understandable to offer a standard dose rather than the high dose depot flupenthixol as there is no difference in relapse. Overall, this review highlights the lack of evidence based information available for the review question and the need for large, well-designed and reported randomised clinical trials to address the medical, social, personal and economic effects of flupenthixol decanoate. This plain language summary has been written by a consumer Ben Gray, Service User and Service User Expert: Rethink Mental Illness.