The study protocol is registered on PROSPERO (CRD42018108829). 
PROSPERO
PubMed, PsycInfo and CINAHL were searched from inception to 25 June 2018. 
PubMed
PubMed, PsycInfo and CINAHL were searched from inception to 25 June 2018. 
PsycInfo
PubMed, PsycInfo and CINAHL were searched from inception to 25 June 2018. 
CINAHL