Polydrug Use Typologies of Regular Ecstasy Users Visiting Electronic Dance Music Events: A Latent Class Analysis.

INTRODUCTION: Polydrug use patterns among young adults using ecstasy vary, as well as their willingness to change them. Polydrug use patterns are likely associated with different adverse health outcomes. It is unknown whether polydrug use patterns of young adults who use ecstasy are similar in different countries. This study aims to identify and compare polydrug use patterns and willingness to change them of young adults that use ecstasy in the United Kingdom (UK) and the Netherlands (NL), two countries with a high prevalence of ecstasy use and a large electronic dance music (EDM) scene. METHODS: The data from the online cross-sectional Electronic Music Scene Survey were used in a latent class analysis. The binary indicators used in the estimation were past-year substance use of 21 different substances. The sample consisted of young adult ecstasy users that regularly visit EDM events (age 18-34). RESULTS: A total of 1,077 respondents from the UK (age M = 23.1) and 1,178 from the NL (age M = 23.7) that regularly visit EDM events were included in the analyses. In both countries, three polydrug use patterns of ecstasy users were identified based on Bayesian Information Criterion fit indices: a traditional polydrug use class (UK: 28%; NL: 40%), a stimulant and ketamine polydrug use class (UK: 48%; NL: 52%), and an extensive polydrug use class (UK: 24%; NL: 8%) characterized by substantial use of stimulants, depressant, and psychedelic substances. Overall, young adults that used ecstasy in the UK consumed 3,4-methylenedioxymeth-amphetamine (MDMA) more often as powder/crystalline and at higher dosages compared to young adults in the NL who preferred MDMA tablets. Regardless of polydrug class or country, most respondents indicated that they had the intention to reduce but not quit their use. CONCLUSION: In both countries, structurally similar polydrug use patterns among young adults that use ecstasy were found, while the use frequencies of individual substances and preferred MDMA form varied between the countries.

Identifying Subgroups of Cannabis Users Based on Help-Seeking Preferences: A Latent Class Analysis.

BACKGROUND: The majority of people with cannabis use disorder do not seek treatment. If we were able to gain more insight into different subgroups of cannabis users based on help-seeking preferences, we could use this information to inform the development and promotion of interventions targeted at specific subgroups of cannabis users, to ultimately narrow the treatment gap. METHODS: An online survey was conducted among 1,015 Dutch frequent cannabis users (18-72 years) to assess their cannabis use, help-seeking preferences, psychopathology, and psychological distress. Latent class analysis was used to identify classes of cannabis users based on their help-seeking preferences. Differences between the identified classes in terms of sociodemographics, cannabis use, and psychopathology were examined. RESULTS: We identified four classes with distinct preferences for support. Class 1 ("no support/only social," n = 548) had a low probability of finding any form of support appealing other than social support. Class 2 ("online help," n = 170) had relatively high probabilities of finding online help appealing. Class 3 ("GP/outpatient," n = 208) had a relatively high probability of finding support from the general practitioner and outpatient substance use disorder treatment appealing. Class 4 ("all sources," n = 89) had moderate to high probabilities for all sources of support. In terms of sociodemographics, differences between the classes were found with regard to gender and level of education. The classes were fairly similar with regard to cannabis use, only the "online help" class scored significantly lower on both cannabis use frequency and quantity compared to most of the other classes. In terms of psychopathology, the "GP/outpatient" class and the "all sources" class experienced more cannabis use-related problems and were more likely to report multiple past quit attempts than the "online help" class and the "no support/only social" class. CONCLUSIONS: Our study shows that there is a lot of inter-individual variation in how appealing various forms of help are to cannabis users. Our findings emphasize the importance of promoting a variety of treatment modalities for cannabis users, including real-life and digital options, and indicate what might appeal to whom.

Drug Use Changes at the Individual Level: Results from a Longitudinal, Multisite Survey in Young Europeans Frequenting the Nightlife Scene.

BACKGROUND: Monitoring emerging trends in the increasingly dynamic European drug market is vital; however, information on change at the individual level is scarce. In the current study, we investigated changes in drug use over 12 months in European nightlife attendees. METHOD: In this longitudinal online survey, changes in substances used, use frequency in continued users, and relative initiation of use at follow-up were assessed for 20 different substances. To take part, participants had to be aged 18-34 years; be from Belgium, Italy, the Netherlands, Sweden, or the UK; and have attended at least 6 electronic music events in the past 12 months at baseline. Of 8,045 volunteers at baseline, 2,897 completed the survey at both time points (36% follow-up rate), in 2017 and 2018. RESULTS: The number of people using ketamine increased by 21% (p < 0.001), and logarithmized frequency of use in those continuing use increased by 15% (p < 0.001; 95% CI: 0.07-0.23). 4-Fluoroamphetamine use decreased by 27% (p < 0.001), and logarithmized frequency of use in continuing users decreased by 15% (p < 0.001, 95% CI: -0.48 to -0.23). The drugs with the greatest proportion of relative initiation at follow-up were synthetic cannabinoids (73%, N = 30), mephedrone (44%, N = 18), alkyl nitrites (42%, N = 147), synthetic dissociatives (41%, N = 15), and prescription opioids (40%, N = 48). CONCLUSIONS: In this European nightlife sample, ketamine was found to have the biggest increase in the past 12 months, which occurred alongside an increase in frequency of use in continuing users. The patterns of uptake and discontinuation of alkyl nitrates, novel psychoactive substances, and prescription opioids provide new information that has not been captured by existing cross-sectional surveys. These findings demonstrate the importance of longitudinal assessments of drug use and highlight the dynamic nature of the European drug landscape.

Effectiveness, Cost-effectiveness, and Cost-Utility of a Digital Alcohol Moderation Intervention for Cancer Survivors: Health Economic Evaluation and Outcomes of a Pragmatic Randomized Controlled Trial.

BACKGROUND: Alcohol moderation (AM) interventions may contribute to better treatment outcomes and the general well-being of cancer survivors. OBJECTIVE: This study evaluates the effectiveness, cost-effectiveness, and cost-utility of MyCourse, a digital AM intervention, compared with a noninteractive digital information brochure for cancer survivors. METHODS: A health economic evaluation alongside a pragmatic 2-arm parallel-group randomized controlled trial was conducted with follow-ups at 3, 6, and 12 months after randomization. The study was conducted on the web in the Netherlands from 2016 to 2019. Participants were adult 10-year cancer survivors drinking over the Dutch-recommended drinking guidelines (≤7 standard units [10 g of alcohol] per week) with the intention to moderate or quit drinking. Overall, 103 participants were randomized and analyzed: 53 (51.5%) in the MyCourse group and 50 (48.5%) in the control group. In the MyCourse group, participants had access to a newly developed, digital, minimally guided AM intervention, MyCourse-Moderate Drinking. The primary outcome was the self-reported number of standard drinks (10 g of ethanol) consumed in the past 7 days at the 6-month follow-up. The secondary outcome measures were alcohol-related problems as measured by the Alcohol Use Disorders Identification Test (AUDIT) and treatment satisfaction. For the health economic evaluation, health care costs, costs because of productivity losses, and intervention costs were assessed over a 12-month horizon. RESULTS: Alcohol use at the 6-month follow-up decreased by 38% in the MyCourse group and by 33% in the control group. No difference in 7-day alcohol use was found between the groups (B=2.1, 95% CI -7.6 to 3.1; P=.22) at any of the follow-ups. AUDIT scores for alcohol-related problems decreased over time in both groups, showing no significant difference between the groups (Cohen d=0.3, 95% CI -0.1 to 0.6; P=.21). Intervention costs per participant were estimated at US $279 for the MyCourse group and US $74 for the control group. The mean societal costs were US $18,092 (SD 25,662) and US $23,496 (SD 34,327), respectively. The MyCourse group led to fewer gained quality-adjusted life years at lower societal costs in the cost-utility analysis. In the cost-effectiveness analysis, the MyCourse group led to a larger reduction in drinking units over time at lower societal costs (incremental cost-effectiveness ratio per reduced drink: US $ -1158, 95% CI -1609 to -781). CONCLUSIONS: At 6 months, alcohol use was reduced by approximately one-third in both groups, with no significant differences between the digital intervention MyCourse and a noninteractive web-based brochure. At 12 months, cost-effectiveness analyses showed that MyCourse led to a larger reduction in drinking units over time, at lower societal costs. The MyCourse group led to marginally fewer gained quality-adjusted life years, also at lower societal costs. TRIAL REGISTRATION: Netherlands Trial Register NTR6010; https://www.trialregister.nl/trial/5433. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s12885-018-4206-z.

Effectiveness, Cost-effectiveness, and Cost-Utility of a Digital Smoking Cessation Intervention for Cancer Survivors: Health Economic Evaluation and Outcomes of a Pragmatic Randomized Controlled Trial.

BACKGROUND: Smoking cessation (SC) interventions may contribute to better treatment outcomes and the general well-being of cancer survivors. OBJECTIVE: This study aims to evaluate the effectiveness, cost-effectiveness, and cost-utility of a digital interactive SC intervention compared with a noninteractive web-based information brochure for cancer survivors. METHODS: A health economic evaluation alongside a pragmatic 2-arm parallel-group randomized controlled trial was conducted with follow-ups at 3, 6, and 12 months. The study was conducted in the Netherlands over the internet from November 2016 to September 2019. The participants were Dutch adult smoking cancer survivors with the intention to quit smoking. In total, 165 participants were included and analyzed: 83 (50.3%) in the MyCourse group and 82 (49.7%) in the control group. In the intervention group, participants had access to a newly developed, digital, minimally guided SC intervention (MyCourse-Quit Smoking). Control group participants received a noninteractive web-based information brochure on SC. Both groups received unrestricted access to usual care. The primary outcome was self-reported 7-day smoking abstinence at the 6-month follow-up. Secondary outcomes were quality-adjusted life years gained, number of cigarettes smoked, nicotine dependence, and treatment satisfaction. For the health economic evaluation, intervention costs, health care costs, and costs stemming from productivity losses were assessed over a 12-month horizon. RESULTS: At the 6-month follow-up, the quit rates were 28% (23/83) and 26% (21/82) in the MyCourse and control groups, respectively (odds ratio 0.47, 95% CI 0.03-7.86; P=.60). In both groups, nicotine dependence scores were reduced at 12 months, and the number of smoked cigarettes was reduced by approximately half. The number of cigarettes decreased more over time, and the MyCourse group demonstrated a significantly greater reduction at the 12-month follow-up (incidence rate ratio 0.87; 95% CI 0.76-1.00; P=.04). Intervention costs were estimated at US $193 per participant for the MyCourse group and US $74 for the control group. The mean per-participant societal costs were US $25,329 (SD US $29,137) and US $21,836 (SD US $25,792), respectively. In the cost-utility analysis, MyCourse was not preferred over the control group from a societal perspective. With smoking behavior as the outcome, the MyCourse group led to marginally better results per reduced pack-year against higher societal costs, with a mean incremental cost-effectiveness ratio of US $52,067 (95% CI US $32,515-US $81,346). CONCLUSIONS: At 6 months, there was no evidence of a differential effect on cessation rates; in both groups, approximately a quarter of the cancer survivors quit smoking and their number of cigarettes smoked was reduced by half. At 12 months, the MyCourse intervention led to a greater reduction in the number of smoked cigarettes, albeit at higher costs than for the control group. No evidence was found for a differential effect on quality-adjusted life years. TRIAL REGISTRATION: The Netherlands Trial Register NTR6011; https://www.trialregister.nl/trial/5434. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s12885-018-4206-z.

The effectiveness of distance-based interventions for smoking cessation and alcohol moderation among cancer survivors: A meta-analysis.

OBJECTIVE: The objective of this study is to evaluate current evidence for the effectiveness of distance-based interventions to support smoking cessation (SC) or alcohol moderation (AM) among cancer survivors. Secondary, differences in effectiveness are explored regarding multibehaviour interventions versus single-behaviour interventions targeting SC or AM only. METHODS: A systematic search of PubMed, PsycINFO, Web of Science, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials was conducted. Intervention studies with and without control groups and randomized controlled trials were included. Random effects meta-analyses were conducted for the main outcomes: SC and AM rates at the follow-up closest to 6 months. Using subgroup analyses and meta-regression, effectiveness of single-behaviour versus multibehaviour interventions was evaluated. RESULTS: A total of 17 studies with 3796 participants; nine studies on SC only, eight studies on multibehaviour interventions including an SC or AM module, and no studies on AM only were included. All studies had at least some concerns regarding bias. Distance-based SC interventions led to higher cessation rates than control conditions (10 studies, odds ratio [OR] = 1.56; 95% CI, 1.13-2.15, P = .007). Single-behaviour SC interventions reduced smoking rates compared with baseline (risk difference [RD] = 0.29; 95% CI, 0.19-0.39, P < .0001), but multibehaviour interventions did not (RD = 0.13; 95% CI, -0.05 to 0.31, P = 0.15). There was insufficient evidence that distance-based multibehaviour interventions reduced alcohol use compared with controls (three studies, standardized mean difference [SMD] = 0.12; 95% CI, -0.08 to 0.31, P = .24). CONCLUSIONS: Distance-based SC interventions are effective in supporting SC among cancer survivors. Single-behaviour SC interventions appear more effective than multibehaviour interventions. No evidence was found for the effectiveness of distance-based AM interventions for cancer survivors.

Internet-based self-help smoking cessation and alcohol moderation interventions for cancer survivors: a study protocol of two RCTs.

BACKGROUND: Brief interventions for smoking cessation and alcohol moderation may contribute considerably to the prevention of cancer among populations at risk, such as cancer survivors, in addition to improving their general wellbeing. There is accumulating evidence for the effectiveness of internet-based brief health behaviour interventions. The objective of this study is to assess the effectiveness, patient-level cost-effectiveness and cost-utility of two new online theory-based self-help interventions among adult cancer survivors in the Netherlands. One of the interventions focuses on alcohol moderation, the other on smoking cessation. Both interventions are tailored to cancer survivors. METHODS: Effectiveness will be assessed in two separate, nearly identical 2-armed RCTs: alcohol moderation (AM RCT) and smoking cessation (SC RCT). Participants are randomly allocated to either the intervention groups or the control groups. In the intervention groups, participants have access to one of the newly developed interventions. In the control groups, participants receive an online static information brochure on alcohol (AM RCT) or smoking (SC RCT). Main study outcome parameters are the number of drinks post-randomisation (AM RCT) and tobacco abstinence (SC RCT). In addition, cost-data and possible effect moderators and mediators will be assessed. Both treatments are internet-based minimally guided self-help interventions: MyCourse - Moderate Drinking (in Dutch: MijnKoers - Minderen met Drinken) and MyCourse - Quit Smoking (MijnKoers - Stoppen met Roken). They are based on cognitive behaviour therapy (CBT), motivational interviewing (MI) and acceptance and commitment therapy (ACT). Both interventions are optimized in collaboration with the target population of cancer survivors in focus groups and interviews, and in collaboration with several experts on eHealth, smoking cessation, alcohol misuse and cancer survivorship. DISCUSSION: The present study will add to scientific knowledge on the (cost-)effectiveness of internet-based self-help interventions to aid in smoking cessation or alcohol moderation, working mechanisms and impact on quality of life of cancer survivors. If found effective, these interventions can contribute to providing evidence-based psychosocial oncology care to a growing population of cancer survivors. TRIAL REGISTRATION: Trials are prospectively registered in The Netherlands Trial Register (NTR): NTR6011 (SC RCT), NTR6010 (AM RCT) on 1 September 2016.

Changes in cannabis potency and first-time admissions to drug treatment: a 16-year study in the Netherlands.

BACKGROUND: The number of people entering specialist drug treatment for cannabis problems has increased considerably in recent years. The reasons for this are unclear, but rising cannabis potency could be a contributing factor. METHODS: Cannabis potency data were obtained from an ongoing monitoring programme in the Netherlands. We analysed concentrations of δ-9-tetrahydrocannabinol (THC) from the most popular variety of domestic herbal cannabis sold in each retail outlet (2000-2015). Mixed effects linear regression models examined time-dependent associations between THC and first-time cannabis admissions to specialist drug treatment. Candidate time lags were 0-10 years, based on normative European drug treatment data. RESULTS: THC increased from a mean (95% CI) of 8.62 (7.97-9.27) to 20.38 (19.09-21.67) from 2000 to 2004 and then decreased to 15.31 (14.24-16.38) in 2015. First-time cannabis admissions (per 100 000 inhabitants) rose from 7.08 to 26.36 from 2000 to 2010, and then decreased to 19.82 in 2015. THC was positively associated with treatment entry at lags of 0-9 years, with the strongest association at 5 years, b = 0.370 (0.317-0.424), p < 0.0001. After adjusting for age, sex and non-cannabis drug treatment admissions, these positive associations were attenuated but remained statistically significant at lags of 5-7 years and were again strongest at 5 years, b = 0.082 (0.052-0.111), p < 0.0001. CONCLUSIONS: In this 16-year observational study, we found positive time-dependent associations between changes in cannabis potency and first-time cannabis admissions to drug treatment. These associations are biologically plausible, but their strength after adjustment suggests that other factors are also important.

The Missing=Smoking Assumption: A Fallacy in Internet-Based Smoking Cessation Trials?

INTRODUCTION: In this study, penalized imputation (PI), a common approach to handle missing smoking status data and sometimes referred to as "missing=smoking," is compared with other missing data approaches using data from internet-based smoking cessation trials. Two hypotheses were tested: (1) PI leads to more conservative effect estimates than complete observations analysis; and (2) PI and multiple imputation (MI) lead to similar effect estimates under balanced (equal missingness proportions among the trial arms) and unbalanced missingness. METHODS: First, the outcomes of 22 trials included in a recent Cochrane review on internet-based smoking cessation interventions were reanalyzed using only the complete observations, and after applying PI. Second, in a simulation study outcomes under PI, complete observations analysis, and two types of MI were compared. For this purpose, individual patient data from one of the Cochrane review trials were used. Results of the missing data approaches were compared with reference data without missing observations, upon which balanced and unbalanced missingness scenarios were imposed. RESULTS: In the reanalysis of 22 trials, relative risks (RR = 1.15 [1.00; 1.33]) after PI were nearly identical to those under complete observations analysis (RR = 1.14 [0.98; 1.32]). In the simulation study, PI was the only approach that led to deviations from the reference data beyond its 95% confidence interval. CONCLUSIONS: Analyses after PI led to pooled results equivalent to complete observations analyses. PI also led to significant deviations from the reference in the simulation studies. PI biases the reported effects of interventions, favoring the condition with the lowest proportion of missingness. Therefore, more sophisticated missing data approaches than PI should be applied.

Three-Year Course of Cannabis Dependence and Prediction of Persistence.

AIMS: To examine the course and the predictors of the persistence of cannabis dependence. METHODS: Through cannabis outlets and chain referral, a prospective enriched community cohort of 207 young adults (aged 18-30) with DSM-IV cannabis dependence at baseline (T0) was formed and followed-up after 1.5 (T1) and 3 (T2) years. The presence of cannabis dependence, cannabis-related problems, functional impairment and treatment was assessed using the Composite International Diagnostic Interview (CIDI 3.0) and the Sheehan Disability Scale (SDS). Predictors of persistence were lifetime cannabis abuse and dependence symptoms, cannabis use characteristics, distant vulnerability factors (e.g. childhood adversity, family history of psychological/substance use problems, impulsivity, mental disorders), and proximal stress factors (recent life events, social support). RESULTS: Four groups were distinguished: persistent dependent (DDD: 28.0%), stable non-persistent (DNN: 40.6%), late non-persistent (DDN: 17.9%) and recurrent dependent (DND: 13.5%). At T2, persisters (DDD) reported significantly more (heavy) cannabis use and cannabis problems than non-persisters (DNN/DDN/DND). Treatment seeking for cannabis-related problems was rare, even among persisters (15.5%). The number (OR = 1.23 (1.03-1.48)) and type ('role impairment' OR = 2.85 (1.11-7.31), 'use despite problems' OR = 2.34 (1.15-4.76)) of lifetime cannabis abuse/dependence symptoms were the only independent predictors of persistence with a total explained variance of 8.8%. CONCLUSIONS: Persistence of cannabis dependence in the community is low, difficult to predict, and associated with a negative outcome. The substantial proportion of stable non-persisters suggests that screening and monitoring or low-threshold brief interventions may suffice for many non-treatment-seeking cannabis-dependent people. However, those with many lifetime abuse/dependence symptoms may benefit from more intensive interventions.

Use transition between illegal drugs among Brazilian university students.

PURPOSE: The aim of the present study was to test whether the first use of an illicit drug increases the chance of first use of other illicit drugs. METHOD: The transitions from the first use of a drug to the first use of another drug were analyzed. Comparisons were made between first drug users and non-users. Survival analysis methods were used to compare the cumulative probability of second drug use after adjusting for socio-demographic covariates and the intermediate use of alcohol and/or tobacco. A total of 12,721 Brazilian university students participated in this study. RESULTS: Inhalants and marijuana were used prior to the use of several other drugs, whereas the opposite pattern was not found. Ecstasy was used before other drugs in several instances. Other well-examined drugs, such as amphetamines, cocaine and hallucinogens, were used both before and after other illicit drugs without any marked predominance for either of the two roles. CONCLUSIONS: This study supports the role of the use of marijuana and inhalants almost exclusively before the use of other illicit drugs, whereas the use of ecstasy has an opposite role. These roles could be linked to the prevalence of lifetime use and whether individuals were at an earlier or later age during experimentation.

Digital Smoking Cessation Intervention for Cancer Survivors: Analysis of Predictors and Moderators of Engagement and Outcome Alongside a Randomized Controlled Trial.

BACKGROUND: Recent studies have shown positive, though small, clinical effects of digital smoking cessation (SC) interventions for cancer survivors. However, research on associations among participant characteristics, intervention engagement, and outcomes is limited. OBJECTIVE: This study aimed to explore the predictors and moderators of engagement and outcome of MyCourse-Quit Smoking (in Dutch: "MijnKoers-Stoppen met Roken"), a digital minimally guided intervention for cancer survivors. METHODS: A secondary analysis of data from the randomized controlled trial was performed. The number of cigarettes smoked in the past 7 days at 6-month follow-up was the primary outcome measure. We analyzed interactions among participant characteristics (11 variables), intervention engagement (3 variables), and outcome using robust linear (mixed) modeling. RESULTS: In total, 165 participants were included in this study. Female participants accessed the intervention less often than male participants (B=-11.12; P=.004). A higher Alcohol Use Disorders Identification Test score at baseline was associated with a significantly higher number of logins (B=1.10; P<.001) and diary registrations (B=1.29; P<.001). A higher Fagerström Test for Nicotine Dependence score at baseline in the intervention group was associated with a significantly larger reduction in tobacco use after 6 months (B=-9.86; P=.002). No other associations and no moderating effects were found. CONCLUSIONS: Overall, a limited number of associations was found between participant characteristics, engagement, and outcome, except for gender, problematic alcohol use, and nicotine dependence. Future studies are needed to shed light on how this knowledge can be used to improve the effects of digital SC programs for cancer survivors. TRIAL REGISTRATION: Netherlands Trial register NTR6011/NL5434; https://onderzoekmetmensen.nl/nl/trial/22832.

A guided digital intervention to reduce cannabis use: The ICan randomized controlled trial.

AIMS: To test the effectiveness of a digital intervention to reduce cannabis use (ICan) with adherence-focused guidance compared with educational cannabis information. DESIGN: This was a single-blind randomized controlled trial. Follow-up clinical outcome measurements took place 3 and 6 months after randomization. SETTING: The trial was conducted in the Netherlands. The intervention and guidance took place on-line, with recruitment via Facebook/Instagram advertisement campaigns. PARTICIPANTS: Inclusion criteria were ≥ 18 years, cannabis use on ≥ 3 days/week, the desire to reduce/quit cannabis and using a smartphone. Participants were allocated to either ICan (n = 188) or control (n = 190) (69% male, mean age = 27.5 years). INTERVENTION AND COMPARATOR: ICan is a mobile (web-)application based on motivational interviewing and cognitive behavioural therapy and includes three main components: screening, brief intervention (six modules) and referral to treatment. The control condition consisted of non-interactive educational cannabis information. MEASUREMENTS: Primary outcome was the number of cannabis use days in the 7 days prior to the 6-month follow-up measurement. Secondary outcome measures at 3- and 6-month follow-up were the number of grams of cannabis used and attitudes towards seeking professional help for cannabis use related problems. FINDINGS: Intention-to-treat analysis showed that 6 months after randomization the mean number of cannabis use days in the past 7 days was reduced in both conditions (time P < 0.001), with no significant group × time interaction effect [ICan = 4.17 days, control = 4.31 days, Cohen's dbetween = 0.06, 95% confidence interval (CI) = -0.15, 0.26, P = 0.93]. Three months after randomization the mean number of grams used in the past 7 days was reduced in both conditions, with a significantly larger reduction in the ICan condition (P = 0.009, Cohen's dbetween = 0.15). At 6-month follow-up the significant group × time interaction effect was no longer present (P = 0.30). In both conditions, attitudes towards seeking professional help remained virtually unchanged over time. CONCLUSIONS: A digital intervention to reduce cannabis use (ICan) was more effective than non-interactive educational cannabis information in reducing grams of cannabis used over 3 months, but not more effective at reducing cannabis use days at 6-month follow-up. Cannabis use reductions were maintained in both conditions between 3 and 6 months' follow-up.

Risk assessment of gamma-hydroxybutyric acid (GHB) in the Netherlands.

The Dutch Minister of Health requested the Coordination point Assessment and Monitoring new drugs (CAM) to re-assess the overall risk of GHB. The present paper is a extended redraft of a state of art report used in the risk evaluation procedure. The prevalence of GHB use is low, but the relative proportion of GHB intoxications compared to other illicit drugs is high resulting in a substantial number of GHB related incidents. In recent years the number of GHB intoxications has increased because many inexperienced users seemed unaware of the potential adverse effects, like 'passing out' upon overdosing, a condition where the user is unconsciousness (or comatose) for several hours. The dependence potential of frequent GHB use is now judged by the CAM to be rather high, but users appear not well informed about this risk. In the Netherlands, last month prevalence of GHB use is relatively low (0.2%) and treatment demand is limited (524 of a total of 76,295 referrals to the addiction treatment services in 2010). So far, no public nuisance or criminality associated with GHB use has been reported. The CAM estimated the overall risk potential of GHB use as moderate to high. The Dutch Minister of Health endorsed this conclusion and decided to upgrade GHB to Schedule I (hard drugs) of the Dutch Opium Act.

Is approving esketamine as an antidepressant for treatment resistant depression associated with recreational use and risk perception of ketamine? Results from a longitudinal and cross-sectional survey in nightlife attendees.

BACKGROUND: Esketamine was licensed for use in treatment resistant depression by the European Medicines Agency in December 2019. It is unclear whether this new approval has lowered the risk perception of recreational ketamine use. This is important given a recent increase in recreational ketamine use. METHODS: This study expanded on an existing longitudinal online study of the nightlife scene, by adding an additional longitudinal assessment as well as a new cross-sectional sample. Participants had to be aged 18-34 years, reside in the UK and have attended at least 6 electronic music events in the past year. The likelihood of increasing recreational ketamine use due to the approval, attitudes towards and risk perception of medical ketamine use and experiences resulting from recreational ketamine use were collected after the approval. Changes in ketamine use and frequency were assessed longitudinally before and after the approval. RESULTS: The overall sample size was 2415: 414 longitudinal (57% retention rate) and 2001 new cross-sectional participants. The majority indicated no change in their likelihood of using recreational ketamine due to the approval of esketamine (87%). Longitudinal participants did not indicate an increase in past 12 month use or frequency after the approval. Only one-third of participants reported being aware of the approval. Participants previously aware showed greater overall support for medical use of ketamine than participants previously unaware of the change. However, an equally high risk was assigned to the recreational use of ketamine in both groups. Ketamine users indicated both increases as well as decreases in depression and anxiety as a result of ketamine use. CONCLUSION: The introduction of esketamine as an antidepressant was not associated with a change in the risk perception of recreational ketamine use in most participants, nor was it longitudinally associated with increased use. Potential negative effects of recreational ketamine use on mental health, as users in this sample reported, should be clearly communicated when discussing the benefits of (es-) ketamine in a therapeutic context.

The International Cannabis Toolkit (iCannToolkit): a multidisciplinary expert consensus on minimum standards for measuring cannabis use.

BACKGROUND: The lack of an agreed international minimum approach to measuring cannabis use hinders the integration of multidisciplinary evidence on the psychosocial, neurocognitive, clinical and public health consequences of cannabis use. METHODS: A group of 25 international expert cannabis researchers convened to discuss a multidisciplinary framework for minimum standards to measure cannabis use globally in diverse settings. RESULTS: The expert-based consensus agreed upon a three-layered hierarchical framework. Each layer-universal measures, detailed self-report and biological measures-reflected different research priorities and minimum standards, costs and ease of implementation. Additional work is needed to develop valid and precise assessments. CONCLUSIONS: Consistent use of the proposed framework across research, public health, clinical practice and medical settings would facilitate harmonisation of international evidence on cannabis consumption, related harms and approaches to their mitigation.

[Legislation of New Psychoactive Substances in the Netherlands]. / Nieuwe psychoactieve stoffen in Nederland.

Every year dozens of New Psychoactive Substances (NPS) appear for the first time on the drug market. Many of them will never find their way to a user group. If they do and a NPS is banned because of its harmfulness, a legal variant subsequently appears on the market. That is why more and more countries are opting for a so-called generic legislation, whereby entire groups of NPS are banned in advance. In this way, the Netherlands also wants to restrict the production, trade and availability of NPS and send out a signal that their use is not without risk. The question is what the effectiveness of such an approach will be and what unintended side effects it will have. In any case, it is essential to continue to monitor the market and the use of NPS by means of various indicators and to continue to focus on prevention and providing information about the risks.

ICan, an Internet-based intervention to reduce cannabis use: study protocol for a randomized controlled trial.

BACKGROUND: Heavy cannabis use is associated with adverse physical and mental health effects. Despite available effective treatments, the majority of heavy cannabis users does not seek professional help. Web-based interventions can provide an alternative for cannabis users who are reluctant to seek professional help. Several web-based cannabis interventions are effective in reducing cannabis use; however, the effect sizes are typically small and attrition rates are typically high. This suggests that web-based programs can be an effective cannabis use intervention for some, while others may need additional substance use treatment after completing a web-based intervention. Therefore, it is important that web-based interventions do not solely focus on reducing cannabis use, but also on improving attitudes towards substance use treatment. The Screening Brief Intervention and Referral to Treatment (SBIRT) approach appears to be well suited for the purpose of reducing cannabis use and improving substance use treatment utilization. Based on the SBIRT approach-and based on cognitive behavioral therapy (CBT) and motivational interviewing (MI)-we developed the Internet-based cannabis reduction intervention ICan. METHODS/DESIGN: This protocol paper presents the design of a randomized controlled trial (RCT) in which we evaluate the effectiveness of the ICan intervention compared to four online modules of educational information on cannabis in a sample of Dutch frequent cannabis users. The primary outcome measure is frequency of cannabis use. Secondary outcome measures include the quantity of cannabis used (grams), the attitudes towards seeking help and the number of participants who enter specialized treatment services for cannabis use-related problems. DISCUSSION: To the best of our knowledge, ICan is the first Internet-based intervention for cannabis users that combines screening, a brief intervention-based on CBT and MI-and referral to treatment options. TRIAL REGISTRATION: The study is registered in the Netherlands Trial Register; identifier NL7668 . Registered on 17 April 2019.

Early cannabis use and estimated risk of later onset of depression spells: Epidemiologic evidence from the population-based World Health Organization World Mental Health Survey Initiative.

Early-onset cannabis use is widespread in many countries and might cause later onset of depression. Sound epidemiologic data across countries are missing. The authors estimated the suspected causal association that links early-onset (age <17 years) cannabis use with later-onset (age > or =17 years) risk of a depression spell, using data on 85,088 subjects from 17 countries participating in the population-based World Health Organization World Mental Health Survey Initiative (2001-2005). In all surveys, multistage household probability samples were evaluated with a fully structured diagnostic interview for assessment of psychiatric conditions. The association between early-onset cannabis use and later risk of a depression spell was studied using conditional logistic regression with local area matching of cases and controls, controlling for sex, age, tobacco use, and other mental health problems. The overall association was modest (controlled for sex and age, risk ratio = 1.5, 95% confidence interval: 1.4, 1.7), was statistically robust in 5 countries, and showed no sex difference. The association did not change appreciably with statistical adjustment for mental health problems, except for childhood conduct problems, which reduced the association to nonsignificance. This study did not allow differentiation of levels of cannabis use; this issue deserves consideration in future research.

Stepped-wedge cluster randomised trial of a smoking cessation counselling training programme for midwives treating women with functional health illiteracy and low socioeconomic status (PROMISE): a study protocol.

BACKGROUND: In the Netherlands, midwives are required to use the 'V-MIS' (Minimal Intervention Strategy for Midwives) smoking cessation counselling protocol to help pregnant women quit smoking. This counselling protocol is often poorly implemented in midwifery practices. It may also be less suitable for pregnant woman with low socioeconomic status or functional health illiteracy. We created an adapted version of the V-MIS protocol that is intended to facilitate implementation in midwifery practices: PROMISE (PROtocol for growing up smokefree using a Minimal smoking cessation Intervention Strategy in the Early stages of life). For this adapted protocol, midwives use carbon monoxide meters, storyboard leaflets, and specific communication techniques for women with functional health illiteracy. They will receive a face-to-face training in using these materials and communication techniques. METHODS: The effectiveness and implementation of PROMISE will be tested in a stepped-wedge cluster randomised controlled trial. We will randomise clusters of midwifery practices and departments in hospitals. We will then train them, subsequently, at regular intervals ('steps'). At each step, practices that will receive training cross over from the control condition to the experimental condition. We will measure how well the PROMISE protocol has been implemented by assessing the rate of pregnant women that received detailed smoking cessation counselling from their midwives (primary outcome). Our secondary target group is pregnant women with functional health illiteracy and low socioeconomic status. Among them, we will assess smoking status and health-related outcome before and after pregnancy. DISCUSSION: The PROMISE smoking cessation counselling protocol is intended to help midwives, OB-GYNs, and other obstetrics professionals to support pregnant women with smoking cessation. TRIAL REGISTRATION: Dutch Trial Registry: NTR 6305/NL6158 . Registered on 20 December 2016.