Cross-cultural differences in the association between cannabis use
perception and CUD severity in individuals with cannabis use disorder
L. Schaveling
Student name: Lisanne Schaveling Student number: 11688688
E-mail: lisannes@live.nl
Supervisor: Mw. Dr. J. Cousijn Daily supervisor: Mw. L.N. Kuhns University: University of Amsterdam
Institute: Neuroscience of Addiction Lab (NOFA) Faculty: Faculty of Social and Behavioral Sciences Department: Developmental psychology
Project: Joint Study Date: 26 March 2021
Abstract
Cannabis is the least studied drug in the research field concerning drug use addiction. Concurrently, it is the most commonly used illicit drug on a global level. To address this knowledge gap, current research conducted a cross-cultural comparison of cannabis use perception in individuals with CUD and non-cannabis users from cultures with different cannabis policies. In addition, it was examined whether this cannabis use perception was related to CUD severity in individuals with CUD and if this association differed across cultures. Insights in individual’s cannabis use perception and CUD severity were given with two questionnaires used from a longitudinal neuroimaging study: Joint Study. Subjects consisted of 89 Dutch participants and 33 participants from Texas. The findings showed differences in cannabis use perception across cultures and between individuals with CUD and non-cannabis users. Personal cannabis use perception was related to CUD severity in individuals with CUD. In this association, cross-cultural differences were observed. The findings suggest that individuals in nations with different cannabis policies do have divergent thoughts about cannabis use and that these thoughts are differently related to CUD severity. However, future research is needed in nations with other cultures and divergent cannabis policies to draw cultural conclusions on a global level.
keywords: cannabis use perception, CUD severity, individuals with CUD, non-cannabis users, nationality, CSE, cultural differences, the Netherlands, Texas
Introduction
Of all illicit drugs, cannabis is the most commonly used worldwide (UNODC, 2020). In 2018 there were more than 192 million cannabis users, which corresponds to 3.9% of the global population aged between 18 and 64 (UNODC, 2020). This percentage has been consistently growing every year over the last two decades, especially in the United States. With a percentage of 8.8% of their population using cannabis, the United States globally has the highest prevalence of cannabis use. With this global growth, cannabis use disorder (CUD) has become more prevalent, followed by an increase in demand for treatment (UNODC, 2020). Concurrently, a shortage in the availability of treatments is perceived. While cannabis is the highest used illicit drug worldwide, cannabis is the least studied drug concerning substance abuse and addiction (Prashad, Milligan, Cousijn & Filbey, 2018).
According to the DSM-V, a CUD-diagnosis consists of problematic cannabis use that leads to distress or behavioral impairments (American Psychiatric Association, 2013). The diagnostic criteria are impairment in controlling cannabis use, showing craving behavior, a decrease in school or work performance, and having difficulties with social functioning, as well as physical or psychological problems as a consequence of cannabis use. When two of these criteria occur within twelve months, a CUD diagnosis will be made. An imbalance between an affected cognitive control and motivations is associated with CUD (Cousijn, van Benthem, van der Schee & Spijkermann, 2015). Impaired cognitive control is associated with substance use or pre-existing risk factors. This impairment may manifest itself in difficulties with working memory, decision-making, planning, problem-solving, and organizing (Cousijn, 2015). Motivations can be substance-related cues such as contexts, objects, or emotional states. These cues may lead to attention and craving for the substance, which may lead to approach tendencies (Filbey & DeWitt, 2012). When the imbalance between impaired cognitive control and
motivations continues, dependence may develop. The fronto-parietal and fronto-limbic brain networks play a key role in this process (Cousijn, 2015). The first is important for executive control. More activity in DLPFC and ACC, included in the fronto-parietal network, is related to better performance when seeing cannabis approach trials. This suggests more self-control and may predict less cannabis problem severity (Cousijn et al., 2012). The second plays a role in emotion regulation and integration of motivational information (Cousijn, 2015; Cousijn et al., 2015). The amygdala, included in the fronto-limbic network, shows abnormal activity when processing emotional stimuli in individuals with CUD, depression, or anxiety disorder (Cousijn, 2015).
Importantly, the processing of emotional stimuli may differ across cultures (Han and Ma, 2014). Cultural differences in social brain network activity were observed in a quantitative meta-analysis of Ham and Ma (2014) when processing social interactions. While East Asian cultures show more activity in brain regions involved with inference of other’s mind, the Western cultures show more activity in brain regions involved with self-relevance. These findings suggest that cultural forces shape the way the brain processes information, which might be helpful to fit into a sociocultural environment. In addition, getting exposed to a set of specific behaviors for a longer time might influence brain pathways (Hyde, Tompson, Creswell & Falk, 2015). Dynamic interactions between the brain and the cultural environment might lead to complex behavioral differences, but it is unknown how exactly neurocognitive mechanisms are involved. Cultural differences in processing emotional stimuli suggest that the vulnerability to environmental influence might differ across cultures. Therefore, the influence of environmental factors related to cannabis use might also differ across cultures.
Environmental factors such as peer influence, perceived risk of cannabis use, and social acceptance towards cannabis use may influence cannabis use and this may be culturally dependent (Prashad et al., 2018). For example, peer influence plays an important role in cannabis use initiation during adolescence (Gilman et al., 2016). Findings of Gilman et al. (2016) suggest difficulties in individuals with CUD during decision making after being influenced by opinions of other peers. Chabrol et al. (2006) have investigated the influence of the social environment on cannabis behavior in high-school students. A negative expectation towards cannabis use and having peers in the close social environment (CSE) who are opposed to cannabis use may both work as a protective factor for cannabis use. On the contrary, risk factors for cannabis use may be a positive expectation towards cannabis use and having peers in the CSE who use cannabis.
Perceived risk of cannabis use also plays an important role in cannabis use patterns. The Health Belief Model suggests that perceived risk will contribute to the decision to participate in health-related behaviors like cannabis use (Pacek, Mauro & Martins, 2015). Perceived risk towards cannabis use has decreased over the last two decades, while illicit cannabis use has increased in the states of America that have passed the Medical Marijuana Law (Pacek et al., 2015). The perception of risk was higher in non-cannabis users compared to cannabis users. Since 2016 more than 28 states have passed the Medical Marijuana Law, but Texas is one of the few states in which cannabis is still completely illegal (UNODC, 2020). Besides a decrease in risk perception of cannabis use and an increase in actual cannabis use, there is also an increase of individuals that do suffer from CUD in the United States (Hasin et al., 2017). In contrast, the perceived risk of cannabis use remained consistent over the last decade in Europe and includes a higher percentage of individuals that perceive cannabis as risky compared to the United States (Prashad et al., 2015). Focusing on Europe, the Netherlands has exceptional history of cannabis use decriminalization compared to other nations. Although this decriminalization law is already
lasting since the 1970s, a positive trend of cannabis use can still be observed (UNODC, 2020). While the perception of cannabis use might be the result of cultural forces, divergent cannabis policies across cultures should also be taken into account.
Taken together, factors such as being susceptible to social influence, having peers in the CSE who use cannabis, and having a low perception of risk towards cannabis might influence the cannabis behavior of an individual negatively. Also, when neural responses of socioenvironmental factors are influenced by culture, the sensitivity for and the development of CUD might differ across cultures. These findings provide insight into how the social environment might be related to cannabis use. However, information about individuals with CUD is missing. It remains unclear if there is a relationship between CUD severity in individuals with CUD and their perception of cannabis use, the cannabis use perception of their social environment, and the cannabis use perception of their nation. Also, information on potential cultural differences in this relationship is missing. In current research, culture is defined as an environment where specific behaviors are used for a long period. Comparing data collection of two culturally-bipolar cannabis using populations with divergent cannabis policies may give an insight into cultural differences or similarities towards cannabis use and the relationship between cultural beliefs of cannabis use, actual cannabis use, and related problems. To address this knowledge gap, the goal of current study was to make a cross-cultural comparison of cannabis use perception in cultures with different cannabis policies, added by examining potential differences in the perception of cannabis use in individuals with CUD and non-cannabis users. Also, the relationship between the CUD severity of individuals with CUD and their perception of cannabis use, the perception of CUD individual’s CSE, and the perception of their nation was examined. Lastly, potential cultural differences in this relationship were also investigated, leading to the following hypotheses:
H1: The perception of cannabis use will be more positive in the Netherlands compared to the perception in Texas in both individuals with CUD and non-cannabis users for each perception (individual, CSE, and nation).
H2: Individuals with CUD will have a more positive perception of cannabis use compared to non-cannabis users in both nationalities. The perception of CSE will be more positive in cannabis users compared to non-cannabis users in both nationalities. No significant difference is expected between individuals with CUD and non-cannabis users for the perception of the nation in both nationalities.
H3: The more positive the perception of cannabis use of the individual with CUD and the perception of CSE, the more severe the CUD will be. The perception of the nation will not be a significant predictor of CUD severity.
H4: Cultural differences will be expected in the association between personal cannabis use perception of individuals with CUD and their CUD severity. This is also expected for the perception of CSE. No significant cultural difference is expected in the prediction of CUD severity by perception of nation.
Knowledge of current research might contribute to treatment, intervention, prevention, and educational program improvement, related to cannabis use problems. More insight will be given whether such programs need to differ across cultures and whether a focus on social environment is needed to prevent severe CUD. It also might contribute to the discussion of cannabis legalization and the corresponding policy issues.
Method
Subjects
122 subjects participated in current research with an average age of 22.55±3.43. Data-collection of this cross-cultural research has been done in Texas (33 subjects) and the Netherlands (89 subjects). All subjects could be divided into cannabis use status groups (CUD or control) in each nationality (TX or NL). The CUD groups consisted of 68 individuals with CUD (23 female and 45 male, average age: 22.41±3.51). The control groups consisted of 54 non-cannabis users (30 female and 24 male, average age: 22.72±3.35). The groups were matched on mental health, age, intelligence, gender, and other demographic and drug use variables.
Procedure
Participants were recruited by flyers and social media. Potential participants were screened by exclusion and inclusion criteria that belonged to a longitudinal neuroimaging study: Joint Study, at Neuroscience of Addiction Lab. It was a collaboration project of the University of Amsterdam and the University of Texas Dallas. Inclusion criteria for both control and CUD groups were: aged between 18-30, being right-handed, being a native speaker, hair > 4 cm. Inclusion criteria specific for the CUD group were: last year’s cannabis use >250, meeting minimum CUD severity (score>1), using cannabis at least six days per week, and no other regular drug use (alcohol excluded). Inclusion criteria specific for the control group were: lifetime cannabis use <26 and no other regular drug use (alcohol excluded). The exclusion criteria for both groups were: being pregnant, planning to leave the country, having a psychological disorder (anxiety and depression excluded), using psychotropic medication that affects the central nervous system, having a neurological disorder, having serious brain damage, having a serious medical condition such as diabetes, AUDIT >13, having metal objects in the body or other MRI contraindications. A specific exclusion criterium for the CUD groups was:
planning to quit daily cannabis use. Specific exclusion criteria for the control group were: cannabis use in the last three months and more than two times of cannabis use in the last year. Beforehand, subjects had obtained an information brochure of the study together with an informed consent approved by the Ethics Review Committee of the University of Amsterdam, The Netherlands, or the University of Texas at Dallas, USA. Participants were allowed to quit research any moment without giving any reason. After the participant had signed the informed consent voluntarily, a test session of four hours was conducted that included cannabis craving information, lung capacity measurement, a drug test, cognitive tasks, a one-hour fMRI-scan with cognitive tasks, questionnaires, and saliva and hair collection, see Figure 1.
Figure 1Overview of four hour test session procedure of longitudinal neuroimaging study: Joint Study, at Neuroscience of Addiction Lab. Data used for current research is highlighted in bold.
Measures
Joint Study included the questionnaires needed for current research: The Cannabis culture questionnaire and the Mini-International Neuropsychiatric Interview 7.0 - CUD only. The Cannabis culture questionnaire was used to measure societal norms around cannabis use (Gelfand et al., 2011; Holm, Sandberg, Kolind & Hesse, 2014). With this questionnaire, an insight of perception towards cannabis use was given for individuals with CUD and controls, their CSE, and their nation. The cannabis culture questionnaire consisted of twelve statements,
in which six statements were positively charged towards cannabis use perception and six statements were negatively charged. The statements included topics as the influence of cannabis use on behavior, the influence on the brain, the impact on culture, and whether it is addictive or not. An example of a positive statement from the cannabis culture questionnaire is: “People
can become more creative, expand their consciousness and gain greater insight in life by smoking cannabis.” An example of a negative statement is: “When people start to smoke cannabis, their brains will function poorly.” There were five scale ratings to choose from, 1 =
strongly disagree, 2 = disagree, 3 = neutral, 4 = agree, 5 = strongly agree. Participants needed to choose one option for every statement for their personal perception, the perception of their CSE, and the perception of their nation.
The Mini-International Neuropsychiatric Interview 7.0 - CUD only was used to measure the CUD severity in individuals with CUD (Sheehan et al., 1998; Lecrubier et al., 1997; Amorim, Lecrubier, Weiller, Hergueta & Sheehan, 1998). The questionnaire consisted of twelve questions that included questions of cannabis behavior, cannabis control, withdrawal symptoms, and the impact of cannabis on daily life and on the individual’s environment.
Data analysis
For data analysis of the cannabis culture questionnaire, the scale ratings of the positive statements were kept positive, whereas the scale ratings of the negative statements were turned into negative values. To determine the cannabis use perception score, both scores of the negative and positive statements were summed up for all three perceptions separately: individual, their CSE, and their nation. The higher the score, the more positive the perception towards cannabis use was.
For the data analysis of the Mini-International Neuropsychiatric Interview 7.0 - CUD only, the questions answered with YES in bold needed to be summed up. The CUD severity
score depended on the number of questions answered with YES. The more questions answered with YES, the more severe the CUD severity score was.
Statistical data analysis
To examine differences in the perception of cannabis use across cultures in individuals with CUD and non-cannabis users, a two-way independent ANOVA was conducted. The two factors were nationality (TX and NL) and cannabis use status (CUD and control). The perception of cannabis use was the dependent variable, used for each perception separately (individual, CSE, and nation). For the significant interaction effects, a simple main effect analysis was conducted as post-hoc with a pairwise comparison.
To examine whether cannabis use perception was related to CUD severity, hierarchical multiple regression was conducted. The dependent variable was the CUD severity score of individuals with CUD. The factors were the cannabis use perception of individuals with CUD, the perception of their CSE, and the perception of their nation, added in that respective order in the first three hierarchies. To examine any cultural differences in this association, nationality (TX or NL) was added as new factor in the last three hierarchies. It was used for interaction with cannabis use perception of individuals with CUD, perception of their CSE, and perception of their nation.
To verify that cannabis users and controls were matched on demographic variables of age and education, a two-way independent ANOVA was conducted. For demographic information of gender, a chi-square test was conducted. All statistical analyses were conducted in R-Studio, in which a significance alpha level of .05 was applied (RStudio Team, 2020).
Results
Assumptions
For the chi-square test, the assumptions were met. For the two-way independent ANOVAs, all assumptions were met, except normal distribution. A minority of the subgroups had violated the assumption of normal distribution (p<.05). The F-test controls Type I error when data is not normally distributed, regardless of equal sample size distribution in the subgroups (Blanca, Alarcón, Arnau, Bono & Bendayan, 2017). Therefore, the F-ratio remains accurate under a non-normality condition, which indicates that a two-way independent ANOVA is robust for the violation of normal distribution. So, a non-parametric test was not conducted. For the hierarchical multiple regression, most assumptions were met. Only multicollinearity was violated for the interaction between personal cannabis use perception of individuals with CUD and nationality. In the other perceptions, no violation of multicollinearity was observed, also when the interaction of nationality was included. Violation of multicollinearity indicates a correlation between two or more predictors. With this violation, standard errors increase. This can result in non-significant results of some variables that should be officially significant (Daoud, 2017). However, when the variables still have significant results, we can infer that multicollinearity did not affect our statistical inferences. Since a significant association between CUD severity and the interaction of nationality with personal cannabis use perception of individuals with CUD was observed, this violation did not affect the results. Therefore, a non-parametric regression was not conducted.
Group characteristics
For gender, a significant difference between cannabis use status across nationalities was observed (χ2 (3, N = 122) = 10.13, p = .017). Overall, more men than women participated in
between nationalities was observed (F(1,118) = 7.88, p = .006). The mean age of the control and CUD groups in Texas was higher compared to the mean age of the control and CUD groups in the Netherlands. For the number of education years, an interaction effect was observed between cannabis use status and nationality (F(1,118) = 4.97, p = .028). Post-hoc analysis indicated that there was only a difference between the control groups across nationalities (p<.001). The number of education years was significantly higher in the Netherlands compared to Texas. This difference was not significant between the CUD groups. See Table 1 for more demographic information of all groups.
Table 1 Group characteristics
Abbreviations: CUDs = Cannabis use disorder individuals, CUD (NL) = Cannabis use disorder individuals from the Netherlands, CUD (TX) = Cannabis use disorder individuals from Texas, control (NL) = control individuals from the Netherlands, control (TX) = control individuals from Texas, n= number of participants per subgroup, SD = standard deviation
**p<.01 for nationality ***p<.001 for controls
The cannabis use perception of individual, CSE, and nation across nationalities within individuals with CUD and non-cannabis users
For personal perception of cannabis use, a significant interaction effect was observed between cannabis use status and nationality (F(1,118) = 55.14, p<.001). Post-hoc analysis indicated that there was a significant difference between the CUD groups across nationalities. Personal perception of cannabis use was more positive in the CUD group in Texas compared to the CUD group in the Netherlands. No significant difference was observed between the control groups. Post-hoc analysis also indicated significant differences between cannabis use status in each nationality. Within the Netherlands, the personal perception of cannabis use in the control group was more positive compared to the CUD group. Remarkably, the opposite was observed for cannabis use status in Texas. See Figure 2 and Table 2 for results.
Demographics CUDs Controls
Overall CUD (NL) CUD (TX) Overall control (NL) control (TX)
n (% male) 45 (66.2%) 37 (69.8%) 8 (53.3%) 24 (44.4%) 19 (52.8%) 5 (27.8%) Age, mean (SD) 22.41 (3.51) 21.89 (3.53)** 24.27 (2.81)** 22.72 (3.35) 22.22 (3.11)** 23.72 (3.68)** Education years, mean (SD) 16.13 (2.51) 16.38 (2.68) 15.23 (1.50) 16.50 (2.75) 17.61 (2.26)*** 14.28 (2.29)***
For cannabis use perception of CSE, a significant interaction effect was observed between cannabis use status and nationality (F(1,118) = 7.72, p = .006). Post-hoc analysis indicated that there was a significant difference between the control groups across nationalities. The CSE perception of cannabis use in the control group of the Netherlands was more positive compared to the control group of Texas. No significant difference in nationality was observed between the CUD groups. Post-hoc analysis also indicated that there was only a significant difference across cannabis use status in Texas. The cannabis use perception of CSE was more positive in the CUD group compared to the control group. No significant difference was observed in cannabis use status in the Netherlands. See Figure 3 and Table 2 for results.
For cannabis use perception of nation, no significant interaction effect was observed between cannabis use status and nationality (F(1,118) = .09, p = 0.760). However, a significant main effect was observed between cannabis use status (F(1,118) = 6.94, p = .010) and between nationalities (F(1,118) = 54.37, p<.001). Cannabis use perception of nation was more positive in the CUD group compared to the control group in both nationalities. Also, cannabis use perception of nation was more positive in both cannabis use status groups in the Netherlands compared to the cannabis use status groups in Texas. See Figure 4 for results.
Table 2 Simple main effect analysis as post hoc with pairwise comparison
Abbreviations: CUD (NL) = Cannabis use disorder participants from the Netherlands, CUD (TX) = Cannabis use disorder participants from Texas, control (NL) = control participants from the Netherlands, control (TX) = control participants from Texas, SE= Standard Error, Sig.= Significance level
Pairwise comparison
Cannabis use perception of: Mean difference SE Sig.
Individual CUD (NL) CUD (TX) -20.66 2.01 <.001***
CON (NL) CON (TX) 0.36 1.99 0.998
CUD (NL) CON (NL) 7.73 1.49 <.001***
CUD (TX) CON (TX) -13.29 2.41 <.001***
Close social environment CUD (NL) CUD (TX) -1.90 2.40 0.859
CON (NL) CON (TX) 7.47 2.37 .011**
CUD (NL) CON (NL) 1.88 1.77 0.714
Figure 2 The perception of cannabis use of the individuals was measured with the cannabis culture questionnaire. A significant difference was observed between the CUD groups (p<.001) and between cannabis use status per nationality (p<.001).
Figure 3 The perception of cannabis use of individual’s CSE was measured with the cannabis culture questionnaire. A significant difference was observed between the control groups (p = .011) and between cannabis use status in Texas (p = .049).
Figure 4 The perception of cannabis use of individual’s nation was measured with the cannabis culture questionnaire. A significant difference was observed between nationalities (p<.001) and the CUD groups were more positive than the control groups (p = .010).
The association between CUD severity and perception of cannabis use in individuals with CUD
Individual perception of cannabis use of individuals with CUD was the only significant predictor of CUD severity, with more positive personal perception of cannabis use related to higher CUD severity. This association was no longer significant after adding perception of CSE and perception of nation to the model. However, the perception of CSE independently was a significant predictor of CUD severity, also with a positive association (β = 0.27, t(66) = 2.25, p = 0.028). For the association of perception of nation with CUD severity no significant result was observed (β = -0.16, t(66) = -1.30, p = 0.199). See Figure 5 and Table 3 for results.
To look for cultural differences, interaction of nationality with cannabis use perception was added to the model per perception (individual, CSE, and nation). An interaction of nationality with personal perception of cannabis use was the only significant predictor of CUD severity. This indicated a significant cultural difference in the prediction of CUD severity by personal cannabis use perception of individuals with CUD. In the Netherlands, the personal perception of cannabis use was positively related to CUD severity. In Texas, more positive personal perception of cannabis use was related to lower CUD severity. For cannabis use perception of CSE and nation, no significant differences were observed across nationalities. See Figure 6 and Table 3 for results.
Table 3 Multiple regression of CUD severity prediction by cannabis use perception
Abbreviations: CUD= cannabis use disorder, CSE = close social environment, R^2 = adjusted R squared, DF= degrees of freedom, F-stat= F-statistic, B = Estimate, SE B= Standard Error, β = Standardized beta estimate, Sig.= Significance level
Figure 5 The association between Figure 6 The association between
CUD severity and the perception CUD severity and the perception of cannabis use of the CUD indiv- of cannabis use of the CUD indiv- idual, their close social environm- idual, their close social environm- ent and their nation. ent and their nation per nationality.
Cannabis use perception R^2 DF F-stat t-value B SE B β Sig.
Hierarchy 1 .06 1, 66 5.51
Constant 20.52 5.51 0.27 <.001***
Perception of CUD individual 3.35 .06 .02 0.28 .022*
Hierarchy 2 .09 2, 65 4.21
Constant 19.91 5.41 0.27 <.001***
Perception of CUD individual 1.79 .05 .03 0.22 .08
Perception of CUD individual's CSE 1.66 .06 .03 0.20 0.10
Hierarchy 3 .09 3, 64 3.14
Constant 18.54 5.53 0.30 <.001***
Perception of CUD individual 1.08 .03 .03 0.15 0.286
Perception of CUD individual's CSE 1.90 .07 .04 0.24 .063
Perception of CUD individual's nation -1.00 -.04 .04 -0.14 0.321
Hierarchy 4 .21
Constant 5, 62 4.51 13.88 6.03 0.43 <.001***
Perception of CUD individual 2.75 0.12 .04 0.57 .008**
Perception of CUD individual's CSE 1.82 .06 .03 0.22 .073
Perception of CUD individual's nation -0.45 -.02 .04 -.06 0.654
Perception of CUD individual*Nationality -3.15 -0.38 0.12 -1.79 .003**
Hierarchy 5 .20 6, 61 3.76
Constant 13.61 6.00 0.44 <.001***
Perception of CUD individual 2.59 0.12 .05 0.55 .012*
Perception of CUD individual's CSE 1.84 .07 .04 0.26 .071
Perception of CUD individual's nation 1.70 -.02 .04 -.07 0.641
Perception of CUD individual*Nationality -2.70 -0.35 0.13 -1.67 .009** Perception of CUD individual's CSE*Nationality -0.53 -.04 .08 -0.15 0.600
Hierarchy 6 .20 7, 60 3.44
Constant 13.38 6.16 0.46 <.001***
Perception of CUD individual 2.44 0.11 .05 0.52 .018*
Perception of CUD individual's CSE 2.01 .08 .04 0.28 .049*
Perception of CUD individual's nation -1.06 -.05 .05 -0.18 0.300
Perception of CUD individual*Nationality -2.92 -0.39 0.13 -1.87 .005** Perception of CUD individual's CSE*Nationality -0.75 -.06 .08 -0.21 0.457 Perception of CUD individual's nation*Nationality 1.17 0.10 .08 0.34 0.248
Discussion
The goal of this study was to make a cross-cultural comparison of cannabis use perception in individuals with CUD and non-cannabis users from cultures with different cannabis policies. In addition, it was examined whether this perception was related to CUD severity in individuals with CUD, since this association remained unclear within these individuals. Also for this association, a cross-cultural comparison was examined. Current research addressed the knowledge gap of cross-cultural differences in individuals with CUD and non-cannabis users by giving insight into cultural beliefs of cannabis use, actual cannabis use, and related problems.
The first hypothesis expected a more positive perception of cannabis use in the Netherlands compared to Texas in both individuals with CUD and non-cannabis users for all three perceptions (individual, CSE, and nation). According to the findings, it can be concluded that there is only evidence for this hypothesis for cannabis use perception of nation. This might be explained by the cultural difference in cannabis policies. The decriminalization policy in the Netherlands that tolerates cannabis use seems to be related to a more positive perception towards cannabis use nationwide. The relatively positive policy towards cannabis use may have resulted in a more open-minded perception towards cannabis use in Dutch inhabitants in general. In addition, a nation with an illegal cannabis policy that does not allow cannabis use seems to be related to more negative thoughts towards cannabis use nationwide. For personal perception of cannabis use, only a significant difference across nationalities was found in individuals with CUD. In Texas, these individuals had a more positive perception towards cannabis use compared to the individuals in the Netherlands. The strong difference between the individuals with CUD from the Netherlands and Texas may be explained by different factors. Individuals with CUD that do suffer from the disorder may have general negative feelings since one of the diagnostic criteria of CUD includes psychological problems (American Psychiatric
Association, 2013). These cannabis-related psychological problems may result in relatively negative thoughts towards cannabis use. However, this reasoning was only observed in the Netherlands. An explanation for Texas may be that actual cannabis use and being against the illegal policy result in stronger positive thoughts about cannabis use. In addition, Dutch individuals with CUD may have low self-esteem concerning their cannabis usage control, since they live in a society in which others are capable of controlling their cannabis use behavior. This confrontation may strengthen these relatively negative thoughts about cannabis use. No difference was found between non-cannabis users across nationalities. For cannabis use perception of CSE, the opposite was observed. No differences were found across nationalities in individuals with CUD, and non-cannabis users in the Netherlands had a more positive cannabis use perception compared to Texas. The positive CSE perception of non-cannabis users in the Netherlands may also be explained by the more open-minded perception towards cannabis use in Dutch inhabitants. Besides the differences in cannabis policies, other cultural and personal factors also should be taken into account for the difference in cannabis use perception across cultures.
In the second hypothesis, a difference in cannabis use perception between individuals with CUD and non-cannabis users was expected. Personal perception and the perception of CSE were hypothesized to be more positive in individuals with CUD compared to non-cannabis users. It can be concluded that there is only evidence for this hypothesis in Texas. This finding suggests that positive thoughts towards cannabis use seem to be related to actual cannabis users and their environment, only in a nation that applies an illegal cannabis policy. As mentioned above, an explanation for this finding may be that resistance to the policy strengthens the positive cannabis use thoughts. Also, as for nationwide, the illegal cannabis policy may be an explanation for the negative thoughts of the non-cannabis users and their environment. With this policy, cannabis is not commonly used or accepted in most social settings, which may result
in negative thoughts in individuals that do not use cannabis. In the Netherlands, the personal perception of cannabis use was more positive in non-cannabis users compared to individuals with CUD. As mentioned above, explanations for this finding may be an open-minded perception towards cannabis use in non-cannabis users and the psychological problems in individuals with CUD. For perception of CSE, no significant difference was found between individuals with CUD and non-cannabis users in the Netherlands. For the perception of nation, no difference between individuals with CUD and non-cannabis users was expected. According to the findings, no evidence for this hypothesis was found. In both nationalities, individuals with CUD scored the perception of nation significantly higher compared to non-cannabis users. This suggests that regardless of culture, individuals with CUD do estimate the overall perception of their nation more positively than non-cannabis users.
Focusing on the association between the perception of cannabis use and CUD severity in individuals with CUD, a more positive perception of cannabis use of individual and CSE were hypothesized to be related to higher CUD severity in the third hypothesis. According to the findings, it can be concluded that there is only evidence for these hypotheses when looking at the perceptions separately. Personal and CSE perception were significantly related to CUD severity, with a positive association. However, when perception of CSE was added to personal perception, a significant prediction was no longer observed. Since personal perception is always present, it can be concluded that only personal perception is related to CUD severity of individuals with CUD. The finding of the association between personal cannabis use perception and CUD severity suggests that the more positive individuals with CUD are about cannabis use, the more severe their CUD is. This finding is in line with the finding of Chabrol et al. (2006), in which was suggested that a positive expectation towards cannabis use could work as a potential risk factor in students. However, in the Netherlands non-cannabis users had a more positive perception compared to individuals with CUD. So, it should be taken into account that
other personal factors also play a role in the development of CUD and the severity of it. The perception of nation was hypothesized to be no predictor of CUD severity. Evidence for this hypothesis was found since no significant relation was observed for the perception of nation with CUD severity.
The last hypothesis focused on cultural differences in the association between the perception of cannabis use and CUD severity in individuals with CUD. Expected was a cultural difference in the association between CUD severity and personal and CSE perception. According to the findings, it can be concluded that there is only evidence for the hypothesis of personal perception. The association between personal cannabis use perception and CUD severity included opposite directions across nations, suggesting that this association was culturally dependent. In the Netherlands, more positive cannabis use perception was related to higher CUD severity. On the contrary, more positive cannabis use perception was related to less CUD severity in Texas. The remarkable finding in Texas is not in line with the finding of Chabrol et al. (2006), suggesting that positive cannabis use perception as a risk factor may be culturally dependent. An explanation may be that substance use dependence is associated with criminality in Western cultures in which substances as cannabis are illegal (Suissa, 2001). In contrast, Western cultures in which cannabis is legalized or tolerated, do accept substance use dependence as a disease. Suissa (2001) suggests that the image of criminality can result in social exclusion since psychosocial issues related to CUD are not accepted as a disease in such societies. Given that individuals with CUD from Texas do live in a nation in which cannabis use is forbidden and not socially accepted, these individuals may feel more excluded from society when the CUD gets more severe. This may result in stronger negative perceptions towards cannabis use. Remarkably, figure 2 indicated a mean score of 12 for the personal perception of individuals with CUD in Texas, suggesting a positive perception on average. In addition, the mean score of the individuals with CUD in the Netherlands was around -5,
suggesting a negative perception on average. Figure 6 indicated that the corresponding mean score of CUD severity, for these personal perception scores, was close to 6 for both nationalities. This suggests that CUD severity is nearly equal across cultures. The score 6 includes the category severe of the Mini-International Neuropsychiatric Interview 7.0 - CUD only, which suggests that the average CUD severity in individuals with CUD is very serious in different cultures. Lastly, no cultural difference for the association between CUD severity and perception of nation was hypothesized. Evidence for this hypothesis is found. No significant difference across nationalities in the association between national perception and CUD severity was observed.
Since cannabis is the least studied drug in the research field of substance addiction, current research has given new important insights into cultural differences and similarities related to CUD (Prashad et al., 2018). Firstly, cross-cultural comparisons between two nations with divergent cannabis policies were novel, since little was known about cultural differences in CUD. Also, current study was exceptional for having researched subjects of a vulnerable group, as researching with vulnerable individuals is rare. The influence of social environment on cannabis use behavior was already studied in students, but no such association was examined within individuals with CUD (Chabrol et al., 2006). The finding of the association between personal cannabis use perception and CUD severity suggests that focusing on cannabis use perception in treatment-, intervention- and educational programs may be valuable. Additionally, the cultural differences in this association suggest that the set-up of the program concerning this topic may need to differ across cultures.
One limitation of current study is the difference in group characteristics across cultures. Firstly, the Dutch sample size consisted of 89 subjects, while in Texas only 33 subjects participated.
Secondly, the average age was significantly higher in the subjects of Texas compared to the subjects in the Netherlands. Thirdly, the number of education years was significantly higher among non-cannabis users in the Netherlands compared to non-cannabis users in Texas. These differences in group characteristics could have given wrong reflections of the cultural comparisons that were conducted. The number of education years gives an indication of educational attainment, in which more education years do suggest higher educational attainment. Educational attainment and age may potentially affect the perception of cannabis use. High educational attainment and or older age may both result in possession of more general knowledge about substance abuse. The opposite may be the result of lower educational attainment and or younger age. The differences in group characteristics can be attributed to force majeure. Due to the Covid-19 pandemic, Texas got behind schedule with testing participants. Once Texas has reached the same number of participants as the Netherlands and has corrected for age and education years, it may be worth repeating the same study as future research. In this manner, a more adequate cultural comparison can be conducted with equal group characteristics in each subgroup. Another limitation is the subjectiveness of the cannabis use perception of the CSE and nation. In the cannabis culture questionnaire, participants needed to estimate the cannabis use perception of their CSE and their nation. Since these perceptions were not asked to the CSE and nation themselves, it should be taken into account that these scores may not represent a realistic vision about their perceptions.
In current research, a comparison was conducted between nations with divergent cannabis use policies. Since both nations were Western cultures, insights in comparisons with East Asian cultures are missing. It is known that social brain network activity differs across cultures when emotional stimuli need to be processed (Ham and Ma, 2014). Since East Asian cultures show differences in brain activity related to social interactions compared to Western cultures, it can
be interesting to compare the Netherlands to an East Asian nation in which cannabis is still completely illegal, like Indonesia. Another variation of current research may be a comparison between the Netherlands and a nation in which cannabis use is legalized for only medicinal use. This can be done with a state in the United States, but also a comparison with an East Asian nation that applies a medicinal cannabis policy (Thailand) may be interesting. Making different combinations in these comparisons between nations with different cannabis policies and different cultures can give better insight into cultural differences in cannabis use perception and the possible association with CUD severity on a global level. Furthermore, information about the amount of cannabis use is missing in current research. Since it remains unknown if CUD severity is positively associated with cannabis use severity in all cultures, future research can examine whether there is an association between cannabis use severity and CUD severity and if this relationship differs across cultures. In addition, it can be examined whether cannabis use severity is related to cannabis use perception by replacing CUD severity with cannabis use severity in the hierarchical regression model.
Summarized, perception of cannabis use differed between individuals with CUD and non-cannabis users across cultures with divergent non-cannabis policies. Personal perception of non-cannabis use was related to CUD severity. However, the direction of this association differed across cultures, with a positive association in the Netherlands and a negative association in Texas. These findings of cross-cultural differences are important insights for the research field of cannabis and CUD. However, more research between other cultures with different cannabis policies is needed to conclude about cannabis use perception and its possible association with CUD severity on a global level.
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