“…However, one study included participants over the age of 50 (Thiessen et al, 2018). Of the 17 studies, 14 focused on MDMA (Gerra et al, 2000;Gerra et al, 2001;Verheyden et al, 2002;Verheyden et al, 2003;Bond et al, 2004;Curran et al, 2004;Hoshi et al, 2004;Hendrickson and Gerstein, 2005;Hoshi et al, 2006;Hoshi et al, 2007;Reid et al, 2007;Scott et al, 2013;Vaughn et al, 2015;Romero-Martínez et al, 2019). Out of the three non-MDMA studies, only one study (Thiessen et al, 2018) assessed classic psychedelics as the main substance of research focus whereas the other two grouped hallucinogens into a broad category encompassing both classic and non-classic psychedelics (Feingold et al, 2008;Walsh et al, 2016).…”