First, while we incorporated extensive checks to prevent multiple registrations by one person, we relied on self-report regarding cannabis use both at the time of recruitment and at follow-up. Second, the outcome measures employed were fairly crude. Perhaps, in an environment where cannabis is legal, the variable number of days used cannabis in the past 30 might suffer from a ceiling effect if a substantial proportion of participants are using cannabis every day. Finally, while the trial was powered to detect a small effect, it is certainly possible that the intervention, if effective, would only ever have an impact that is very small; especially among heavy users of cannabis. Given that this is a low-cost intervention that can be distributed widely, having a very small impact is not necessarily a rule-out of the intervention’s utility. It just implies that a much larger sample would be needed to establish efficacy,vertical grow rack system perhaps across a wider range of cannabis users.
Participants were college students recruited to participate in an online survey from 7 countries between February 2019 and March 2020 . In the present study, participants that reported consuming cannabis at least once in their lifetime and completed the CUDIT-R were included in the psychometric analyses. Analyses examining correlations between the CUDIT-R and non-CUDIT-R measures were limited to 2402 students that reported cannabis consumption during the last 30 days . For the U.S., Canadian, England, and South African sites, students were recruited from psychology department pools and received research participation credits. In Argentina and Uruguay, students were recruited through online social networks, e-mail listings and flyers , and those who completed the survey were entered into a raffle for prizes. In Spain an email was sent to all the students of the university inviting them to participate in the research. The participants received 5 euros for completing the survey. Study procedures were approved by the institutional review boards at the participating universities.
However, limited research has tested the measurement invariance of the questionnaire across different countries. Thus,vertical rack grow a main aim of the present research was to test the measurement invariance of the CUDIT-R among college students from seven countries. The results showed that the measure was invariant at different levels among the U.S., Canada, Argentina, Spain, and South African samples suggesting that the CUDIT-R is a suitable measure to compare cannabis-related problems among students from these five countries. Due to their low item endorsement, it was not possible to the test the invariance of the questionnaire in Uruguay and England. Future studies with a higher sample size of students from these two countries are required. In addition, measurement invariance of the questionnaire across males and females was explored. A previous study performed with a large sample of undergraduates from the U.S. found configural and metric invariance of the measure across gender groups . Our results extend previous findings, showing that the structure , the factor loadings and the thresholds were similar across a sample of males and females from different nationalities and languages.
Scalar invariance of the questionnaire across groups is relevant, as differences in the CUDIT-R scores across countries and gender groups can be interpreted as differences in problematic cannabis use, rather than merely artifacts of other processes, such as the interpretation of items . To this end, when mean comparisons of the CUDIT-R total score were examined, as it is usually found, males showed higher problematic cannabis use than females . We also found lower problematic cannabis use in the Spain and Argentina than in U.S., and also in Spain compared with the rest of the countries. These differences could be related to cannabis polices, as lower rates of CUDIT-R were found in countries in which the access to cannabis is more difficult . The present research also provided reliability evidence of the CUDIT-R scores, showing that both Cronbach’s alphas and ordinal omegas were higher than the standard cut-off of 0.70, and similar to those found in previous studies that have explored the unidimensional structure of the questionnaire . Convergent validity evidence was also provided in five countries, as the CUDIT-R showed large correlations in magnitude with the B-MACQ. The magnitude of these associations was similar to that found in previous studies with undergraduates from the U.S. , suggesting that the Spanish version provided similar convergent validity evidence with the B-MACQ as the English version. Finally, criterion validity evidence of the CUDIT-R scores was provided using different measures of cannabis consumption and cannabis-related motives.