Figure 1 summarises the selection of studies. The search strategy identified 1089 studies from the computerised databases (476 from Medline, 517 from PsycINFO, and 96 from Embase). One additional trial was identified from CENTRAL and clinical.trials.gov. Out of the 1090 studies, 130 were duplicates and 905 were excluded based on screening of titles and abstracts; therefore 55 papers met the criteria for further screening. After the second round of screening, 42 trials were identified for further data extraction.24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Two additional studies were identified when the search was repeated for the week beginning Monday 4 August 2014.66 67 Forty four studies were included in the systematic review. We received responses from study authors for 33 studies (75%).
