“…A frequent obstacle reported in 12 studies is small sample size, which ranged from six to 313 participants per group(25–27,30,31,36,37,42,45,48,51). Other limitations include the absence of longitudinal data(26,34,39,41,45,47,52), self-reported bias for questionnaires(23,24,46,49,50), the lack of comparison to an in-person intervention(35,38,41,44), no follow-up on the number of participants who responded to an opioid poisoning post-intervention(34,42,44,52), lack of validity of the tools used(25,30,32), low response rates, which were of 21.2% and 33.7%(32,50), and the lack of randomization(43,44).…”