Studies excluded because they were not randomised

Allen 1997, Branchey 1981, Breier 1987, Chouinard 1980, Collins 1967, Condray 1995, Curson 1985, Degkwitz 1970, Diamond 1960, Goldberg 1967, Hine 1958, Hunt 1967, Ionescu 1983, Johnstone 1988, Kellam 1971, Mosher 1975, Müller 1982, Paul 1972, Pickar 1986, Pickar 2003, Rassidakis 1970, Singh 1990, Smelson 2006, Van Kammen 1982, Wright 1964, Zeller 1956

Randomised studies excluded because participants were not appropriate ‐ mostly not stable

Bai 2003, Bechdolf 2016, Bourin 2008, Chopra 2019, Chouinard 1993, Clark 1967, Durgam 2016, Engelhardt 1967, Francey 2018, Freedman 1982, Janecek 1963, Lauriello 2005, Lecrubier 1997, Loo 1997, Marder 1994, Meehan 2019, Oosthuizen 2003, Pasamanick 1967, Schlossberg 1978, Soni 1990, Sumitomo 2008, Vanover 2018, Zou 2018, Zwanikken 1973

Randomised studies, with appropriate participants, excluded because interventions were not appropriate ‐ mostly no placebo group

Bo 2017, Brown 2018, Cheng 2019, Claghorn 1974, Double 1993, Fleischhacker 2014, Gleeson 2004, Greenberg 1966, Cather 2018, Keefe 2018, Liu 2018, Nishikawa 1989, NCT03559426, Peet 1981, Ran 2002, Ravaris 1965, Stuerup 2017, Vaddadi 1986, Van Praag 1973, Weller 2018, Wiedemann 2001, Wunderink 2006

Randomised studies, with appropriate participants and interventions, excluded because outcomes were not appropriate ‐ mostly no usable data

Gallant 1964, Gitlin 1988, Gitlin 2001, Good 1958, Hirsch 1989, Hirsch 1996, Mahal 1975, Mathur 1981, Mefferd 1958, Pigache 1993, Ruiz 1975, Ruiz Veguilla 2013, Singer 1971,