... Recent meta-analyses also revealed the feasibility and safety of third-wave interventions for SSD, as well as their effectiveness in reducing positive-, (Cramer, Lauche, Haller, Langhorst, & Dobos, 2016;Louise, Fitzpatrick, Strauss, Rossell, & Thomas, 2017) negative- (Jansen et al., 2020;Khoury, Lecomte, Gaudiano, & Paquin, 2013), and depressive symptoms (Louise et al., 2017). Further research in this field found MBIs to be particularly helpful at reducing psychotic symptoms (Bacon, Farhall, & Fossey, 2014;Gaudiano & Herbert, 2006) and the decreasing severity of negative symptoms (Gaudiano, Nowlan, Brown, Epstein-Lubow, & Miller, 2013;Johnson et al., 2009;Johnson, Penn, Fredrickson, Kring, & Meyer, 2011;White et al., 2011). Some studies also suggest improving social functioning (Gaudiano & Herbert, 2006) and self-esteem (Laithwaite et al., 2009). ...