How Cannabis Users Obtain and Purchase Cannabis: A Comparison of Cannabis Users from European Countries with Different Cannabis Policies.

Objective: This study examines the role of cannabis policy in how cannabis users obtain and purchase cannabis. Methods: A survey was conducted in the Dutch coffeeshops among current cannabis users (n = 1255) aged 18-40 from seven European countries with different cannabis policies. This study investigated whether acquisition methods and supply sources were associated with national cannabis policy, controlling for gender, age, and frequency of use. Results: Cross-national differences notwithstanding, cannabis was easily available to current cannabis users in Europe. Within and across countries, users acquired cannabis in various ways and buyers purchased it from various sources, representing a mixture of open, closed, and semi-open retail markets. Buying cannabis was the most common method of acquisition. Among participants who reported buying their cannabis (n = 929), buying from friends was the most common source of supply, followed by street dealers, home dealers, and delivery services. The vast majority of Dutch participants reported buying cannabis from coffeeshops. Contrariwise, French buyers were more likely to buy cannabis from street dealers and delivery services, and Greek buyers to buy it from home dealers and friends. Overall, the Internet played a marginal role in purchasing cannabis. Conclusion: Our findings confirm the significant role of social supply across Europe. Although cross-national differences were rather common in cannabis acquisition and supply, yet they were not unidirectionally linked with the punitiveness of national cannabis policy. Findings suggest a differentiated normalization of the cannabis retail market, with users often preferring to buy cannabis in a regulated or legal market.

Criminal involvement and crime specialization among crack users in the Netherlands.

BACKGROUND/AIMS: Crack users in the Netherlands are an ageing and diverse population with longstanding criminal careers. Our aim was to assess factors associated with current criminal involvement and specialization in selling drugs, property crime and violence. METHOD: A sample of 1,039 frequent crack users was recruited in three major Dutch cities, combining respondent-driven sampling with random institutional sampling. Bivariate and logistic regression analyses were performed to find factors associated with current criminality. RESULTS: A total of 431 participants (41.5%) had engaged in crime in the past 30 days, mostly selling drugs (68.9%), followed by property crimes (34.4%) and a few cases of violent crime (9.7%). Younger age, homelessness, heavier patterns of use and a more prolific criminal justice history were associated with current criminality. Those receiving welfare benefits tended to be more likely to specialize only in selling drugs as opposed to (also) property crimes. CONCLUSION: Reducing drug use among criminally involved crack users and addressing their housing conditions could have a significant impact on reducing drug-related crime. Welfare benefits might act as protective factor against committing property crimes but not against the selling of drugs.

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.

Exploring the Attractiveness of New Psychoactive Substances (NPS) among Experienced Drug Users.

A growing number of New Psychoactive Substances (NPS) appear yearly on the European market (81 for the first time in 2013, adding to a total of over 350 NPS). Using semi-structured interviews with 25 Dutch experienced recreational drug users, the role of the Internet and friends in gathering and exchanging information about NPS was elaborated. Furthermore, we investigated how NPS were acquired and which aspects make NPS more or less attractive, including their legal status. It appeared that the Internet was an important source of information about NPS in general. Personal experiences with NPS were preferably shared face-to-face with friends, as for privacy reasons users were cautious to post their experiences on web sites and forums. NPS were usually obtained or bought from friends or-to a lesser extent-purchased via the Internet. The preference for a specific NPS depended on the desired effects (mostly stimulant or psychedelic), price (similar to MDMA or amphetamine), duration of effect (preferably around four hours), and setting (at home, at festivals, or in nightlife). Legal status was not relevant for the decision to use NPS. Most NPS are not superior to the already marketed drugs, and do not displace conventional illicit drugs.

Risk factors of γ-hydroxybutyrate overdosing.

The aim of this study was to identify in recreational drug users the factors which increase the risk of overdosing (OD) with γ-hydroxybutyrate (GHB). A purposive sample of 45 experienced GHB users was interviewed, equally divided into three groups (never OD, occasional OD, and repeat OD). The repeat OD group scored highest on many risk factors regarding GHB use, the occasional OD group scored intermediate, and the never OD group scored lowest. Participants, whether or not they had overdosed on GHB, most often perceived GHB use (e.g. using more GHB than usual, using GHB doses too closely together) as the main reason for GHB OD, and many participants who had overdosed on GHB reported that they had taken more GHB than usual at their most recent occasion of GHB OD. No significant differences in co-use of GHB with other substances were found between the three groups. Our findings indicate that using GHB in the company of groups of friends probably reduces, but does not eliminate, the risk of OD.

Estimating the prevalence of crack dependence using capture-recapture with institutional and field data: a three-city study in The Netherlands.

The aim of this study was to estimate the prevalence of crack dependence in the three largest Dutch cities (Amsterdam, Rotterdam, The Hague), stratified by gender and age. Three-sample capture-recapture, using data (collected between 2009 and 2011) from low threshold substitution treatment (n = 1,764), user rooms (n = 546), and a respondent-driven sample (n = 549), and applying log-linear modeling (covariates: gender, age, and city), provided a prevalence rate of 0.51% (95% CI: 0.46%-0.60%) for the population aged 15-64 years, with similar estimates for the three cities. Females (23.0% of total estimate) and younger crack users (12.8% aged <35 years) might be underrepresented in drug user treatment services.

Differential profiles of crack users in respondent-driven and institutional samples: a three-site comparison.

BACKGROUND/AIM: Respondent-driven sampling (RDS) is increasingly applied in social epidemiological surveys among 'hidden populations' of hard drug users. The objective of the present study was to assess whether the profile of frequent crack users recruited through RDS differed from those surveyed in two random institutional samples, i.e. low-threshold opiate substitution treatment (ST) and user rooms (URs). METHODS: A total of 1,039 crack users (mean age 45.1 ± 9.1 years; 81.5% males; 49.5% non-Western ethnicity) were interviewed in three Dutch cities, using each sampling strategy in each city. Characteristics of respondents in the three samples (per city and aggregated) were compared. RESULTS: Crack users in the RDS sample were more likely to be younger and less likely to be poorly educated, have a long crack-using career (≥10 years), use opiates and attend ST than those in both of the other samples. The RDS and UR samples showed the most differences, with more female and Western crack users in the RDS group, and UR participants were more likely to have been arrested and to have entered inpatient drug treatment in the last year. CONCLUSION: RDS resulted in a different profile of crack users. It is a valuable methodology to achieve a more diverse representation of crack-using populations than institutional random samples.

Why do people use new psychoactive substances? Development of a new measurement tool in six European countries.

INTRODUCTION: New psychoactive substances (NPS) pose a public health threat. Many studies have tried to identify the reasons of NPS use; however, none of them have so far used any standardised measures. The aim of this study was (i) to develop and cross-culturally validate the New Psychoactive Substance Use Motives Measure (NPSMM) and (ii) to compare motives of NPS use across countries and user types. METHODS: Three subgroups (socially marginalised users, nightlife attendees and members of online communities) of NPS users (N = 3023) were recruited from six EU member countries. Demographics, motives and types of NPS used were assessed. NPS use motives were measured by adapting the extended six-factor version of the Marijuana Motives Measure. RESULTS: Exploratory and confirmatory factor analysis resulted in a similar five-factor solution across most of the countries: coping, enhancement, social, conformity and expansion motives. Marginalised users scored higher on coping and conformity motives, nightlife groups showed higher endorsement of social motive, whereas online community users showed higher scores on expansion motives. Various types of NPS were also associated with different motives. CONCLUSION: NPS use motives might be associated with both the groups of users and the specific types of NPS being consumed. Expansion (psychedelics) and enhancement (stimulants) motives seemed to be linked to the chosen NPS product type, while coping, social and conformity motives were rather associated with user groups. NPSMM was found to be a valid instrument to measure NPS motives.

Short- and long-term effects of digital prevention and treatment interventions for cannabis use reduction: A systematic review and meta-analysis.

BACKGROUND: Frequent Cannabis use has been linked to a variety of negative mental, physical, and social consequences. We assessed the effects of digital prevention and treatment interventions on Cannabis use reduction in comparison with control conditions. METHODS: Systematic review with two separate meta-analyses. Thirty randomized controlled trials met the inclusion criteria for the review, and 21 were included in the meta-analyses. Primary outcome was self-reported Cannabis use at post-treatment and follow-up. Hedges's g was calculated for all comparisons with non-active control. Risk of bias was examined with the Cochrane risk-of-bias tool. RESULTS: The systematic review included 10 prevention interventions targeting 8138 participants (aged 12 to 20) and 20 treatment interventions targeting 5195 Cannabis users (aged 16 to 40). The meta-analyses showed significantly reduced Cannabis use at post-treatment in the prevention interventions (6 studies, N = 2564, g = 0.33; 95% CI 0.13 to 0.54, p = 0.001) and in the treatment interventions (17 comparisons, N = 3813, g = 0.12; 95% CI 0.02 to 0.22, p = 0.02) as compared with controls. The effects of prevention interventions were maintained at follow-ups of up to 12 months (5 comparisons, N = 2445, g = 0.22; 95% CI 0.12 to 0.33, p < 0.001) but were no longer statistically significant for treatment interventions. CONCLUSIONS: Digital prevention and treatment interventions showed small, significant reduction effects on Cannabis use in diverse target populations at post-treatment compared to controls. For prevention interventions, the post-treatment effects were maintained at follow-up up to 12 months later.

Cognition in novice ecstasy users with minimal exposure to other drugs: a prospective cohort study.

CONTEXT: Ecstasy (street name for [+/-]-3,4-methylenedioxymethamphetamine [MDMA]) use has been associated with cognitive deficits, especially in verbal memory. However, owing to the cross-sectional and retrospective nature of currently available studies, questions remain regarding the causal direction and clinical relevance of these findings. OBJECTIVE: To examine the relationship between Ecstasy use and subsequent cognitive performance. DESIGN: A prospective cohort study in Ecstasy-naive subjects with a high risk for future first Ecstasy use, as part of the Netherlands XTC Toxicity study. The initial examination took place between April 10, 2002, and April 28, 2004; follow-up was within 3 years after the initial examination. SETTING AND PARTICIPANTS: One hundred eighty-eight healthy Ecstasy-naive volunteers (mean age, 22 years) were recruited. Of these, 58 subjects started using Ecstasy (mean cumulative dose, 3.2 tablets; median cumulative dose, 1.5 tablets). They were compared with 60 persistent Ecstasy-naive subjects matched on age, sex, intelligence, and use of substances other than Ecstasy. Differences in cognition between Ecstasy users and Ecstasy-naive subjects were adjusted for differences in cannabis and other recreational drug use. MAIN OUTCOME MEASURES: Change scores between the initial examination and follow-up on neurocognitive tests measuring attention, working memory, verbal and visual memory, and visuospatial ability. RESULTS: At the initial examination, there were no statistically significant differences in any of the neuropsychological test scores between persistent Ecstasy-naive subjects and future Ecstasy users. However, at follow-up, change scores on immediate and delayed verbal recall and verbal recognition were significantly lower in the group of incident Ecstasy users compared with persistent Ecstasy-naive subjects. There were no significant differences on other test scores. CONCLUSIONS: Our findings suggest that even a first low cumulative dose of Ecstasy is associated with decline in verbal memory. Although the performance of the group of incident Ecstasy users is still within the normal range and the immediate clinical relevance of the observed deficits is limited, long-term negative consequences cannot be excluded.

The care-system for homeless youth in The Netherlands: perceptions of youngsters through a peer research approach.

The aim of this study was to examine the perceptions of homeless youth of the care they receive. Since we wanted to involve homeless youth as participants in this project, we adopted the approach of peer-research. This form of collaborative research has a major role for homeless youth in making an inventory of the problems. A parallel is drawn between the parent-adolescent relationship and the relationship between social worker and homeless adolescent.

An Exploratory Study of Cannabis Festivals and Their Attendees in Two European Cities: Amsterdam and Berlin.

This study was designed to explore the nature and features of cannabis festivals, characteristics of festival participants, and reasons for attendance. A field study in two European cities (Amsterdam and Berlin) included participant observation at the festivals, interviews with local organizers, and a survey among festival attendees (n = 728). Both festivals had common features, but also showed distinct differences. At both festivals, nine out of 10 participants were current, often daily cannabis users. Participants were mainly young adults (mean = 26.2 years), but younger in Berlin than in Amsterdam. Common reasons for festival attendance were "protest/activism" and "entertainment." Protest/activism was more likely in Berlin, among daily cannabis users, and participants aged 25+ years. Entertainment was more likely in Amsterdam, among non-daily cannabis users, and participants younger than 25 years. Although similar in political aim, cannabis festivals are characterized by distinctive local features, as well as differences in attendee profile and reasons for festival participation. Findings suggest that the latter differences are driven by differences in cannabis policy, with a stronger tendency towards protest/activism in countries with a less liberal, or more restrictive, cannabis policy. Future research should include more countries, representing a wider variation in cannabis policies.

Health and Social Problems Associated with Recent Novel Psychoactive Substance (NPS) Use Amongst Marginalised, Nightlife and Online Users in Six European Countries.

Continued diversification and use of new psychoactive substances (NPS) across Europe remains a public health challenge. The study describes health and social consequences of recent NPS use as reported in a survey of marginalised, nightlife and online NPS users in the Netherlands, Hungary, Portugal, Ireland, Germany and Poland (n = 3023). Some respondents were unable to categorise NPS they had used. Use of 'herbal blends' and 'synthetic cannabinoids obtained pure' was most reported in Germany, Poland and Hungary, and use of 'branded stimulants' and 'stimulants/empathogens/nootropics obtained pure' was most reported in the Netherlands. Increased heart rate and palpitation, dizziness, anxiety, horror trips and headaches were most commonly reported acute side effects. Marginalised users reported substantially more acute side effects, more mid- and long-term mental and physical problems, and more social problems. Development of country-specific NPS awareness raising initiatives, health and social service needs assessments, and targeted responses are warranted.

How much for a dime bag? An exploration of youth drug markets.

Relatively little is known about how youth obtain marijuana and other drugs. The Drugs, Alcohol and Violence International (DAVI) study explored youthful drug markets among samples of school students, detained youth, and school dropouts (ages 14-17 years) in the greater metropolitan areas of Philadelphia, Toronto, Montreal, and Amsterdam. Students frequently reported sharing drugs, either getting them from others or giving them to others for free. Sharing was less common among the more drug-involved detainees and dropouts. Marijuana was typically obtained either outdoors or in a house or apartment. Few youth reported getting marijuana at school. In Amsterdam, where marijuana can be purchased in small quantities in coffeeshops, this was the most common place to get marijuana, even though 18 is the legal age for purchase. Alcohol was also most likely to be obtained in stores or restaurants across all the sites, even though none were of legal age except those in Amsterdam age 16 or older. Youth most often reported purchasing marijuana in nickel, dime or other small bags, which are not standardized units. The exception again was Amsterdam, where youth most often reported quantities in grams or joints, which is how it is sold in coffeeshops. The lack of standardization of units makes economic cost estimates suspect. Even standardized units such as alcohol present problems since youth report a wide range of 'typical purchases.' Survey data can, however, more aptly describe drug market characteristics such as general location of purchase, and relationship with the seller.

How to find future ecstasy-users: targeted and snowball sampling in an ethically sensitive context.

This article documents the design and the sampling procedures of a prospective longitudinal multidisciplinary study on the neurotoxicity of ecstasy (MDMA): the Netherlands XTC Toxicity Study (NeXT). Targeted and snowball sampling was used to recruit 188 respondents who were ecstasy-naive at baseline. All respondents completed baseline questionnaires and underwent medical and neuropsychological examinations. At the end of a 11- to 26- month follow-up period in which they completed four additional questionnaires, 160 respondents remained (85.1%). A total of 65 participants (40.6%) took ecstasy for the first time during the follow-up period. This paper discusses the ethical dilemmas inherent in a study of this type and the specific problems and solutions that emerged in the sampling. The sampling was tightly constrained by our need to locate respondents who were potential future ecstasy users while also meeting strict medical and technical criteria. The 'intention to use' criterion proved to be a clear-cut inclusion rule that was practical to apply in the fieldwork.

Tightening the Dutch coffee shop policy: Evaluation of the private club and the residence criterion.

BACKGROUND: The Dutch coffee shop policy was tightened in 2012. Two additional criteria that coffee shops must adhere to in order for them to be tolerated came into force: the private club and the residence criterion. Coffee shops were only permitted to give access to members and only residents of the Netherlands were permitted to become a member. This tightened policy sought to make coffee shops smaller and more controllable, to reduce the nuisance associated with coffee shops and to reduce the number of foreign visitors attracted by the coffee shops. Enforcement began in the southern provinces. The private club criterion was abolished at the end of 2012. METHODS: A sample of fourteen municipalities with coffee shops was drawn. Seven in the south were treated as an 'experimental group' and the others as 'comparison group'. A baseline assessment and follow-ups at six and 18 months were performed. A combination of methods was applied: interviews with local experts, surveys with neighbourhood residents, coffee shop visitors and cannabis users, and ethnographic field work. RESULTS: Drugs tourism to coffee shops swiftly declined in 2012. The coffee shops also lost a large portion of their local customers, since users did not want to register as a member. The illegal market expanded. Neighbourhood residents experienced a greater amount of nuisance caused by dealer activities. After abolishment of the private club criterion, residents of the Netherlands largely returned to the coffee shops. Drug tourists still remained largely absent. Neighbourhood residents experienced more nuisance from coffee shops again. Illegal cannabis sale was tempered. No effect on cannabis use was found. CONCLUSION: The quick and robust shifts in the users' market in reaction to the policy changes illustrate the power of policy, but also the limitations caused by the dynamic and resilient nature of the Dutch cannabis supply market.

The Netherlands XTC Toxicity (NeXT) study: objectives and methods of a study investigating causality, course, and clinical relevance.

This paper describes the objectives and methods of The Netherlands XTC Toxicity (NeXT) study focussing on the causality, course, and clinical relevance of ecstasy neurotoxicity. Previous studies suggest that ecstasy (3,4 methylene-dioxymethamphetamine, MDMA, XTC) is toxic toward brain serotonin axons, but most of these studies have serious methodological limitations. The current study is a combination of different approaches with three substudies: (1) a crosssectional substudy among heavy ecstasy users and controls with variation in drug use, which will provide information about potential neurotoxic consequences of ecstasy in relation to other drugs; (2) a prospective cohort substudy in ecstasy-naive subjects with high risk for future ecstasy use, which will provide information on the causality and short-term course of ecstasy use and potential neurotoxicity, and (3) a retrospective cohort substudy in lifetime ecstasy users and matched controls of an existing epidemiological sample that will provide information on long-term course and outcome of ecstasy use in the general population. Neurotoxicity is studied using (a) different imaging techniques (beta-CIT SPECT, 1H-MR spectroscopy, diffusion tensor imaging, perfusion weighted imaging and functional magnetic resonance imaging), and (b) neuropsychological and psychiatric assessments of memory, depression, and personality. The combined results will lead to conclusions that can be used in prevention messages, clinical decision making, and the development of an (inter)national ecstasy policy.

The role of leisure and delinquency in frequent cannabis use and dependence trajectories among young adults.

BACKGROUND: The link between leisure and cannabis use has been widely studied, but less so for young adults, and rarely with a focus on frequent cannabis use. Also, little is known about how changes in leisure develop over time and how they are related to transitions in cannabis use and dependence. METHOD: As part of a 3-year longitudinal project, in a qualitative study 47 frequent male and female young adult cannabis users with (n=23) and without (n=24) dependence at baseline were interviewed in-depth after 1.5 and 3 years. RESULTS: Frequent cannabis users (at baseline ≥3 days per week in the past 12 months) are involved in similar leisure activities as the general young adult population and live rather conventional lives, generally away from a delinquent subculture. They mostly regulate their cannabis use to leisure time, to enhance other leisure activities, including socialising and video gaming. While they often give precedence to responsibilities (e.g. work and study), dependent and non-dependent users differed in whether they actively adapted their leisure activities to their cannabis use, or their cannabis use to their leisure time. Both types of and time spent on leisure activities were associated with transitions in use and dependence. CONCLUSIONS: While our findings generally support the normalisation thesis, it is questionable whether frequent but non-problematic cannabis use is socially accepted in wider society. This study also questions the diagnostic dependence vs. non-dependence dichotomy, and adds finer distinctions to the concept of cannabis dependence. Implications for prevention and treatment include facilitating structured spending of leisure time (e.g. sports), and targeting frequent users who spent much leisure time video gaming at home.

Reliability and validity of the Marijuana Motives Measure among young adult frequent cannabis users and associations with cannabis dependence.

The Marijuana Motives Measure (MMM) has so far been examined mainly in student populations, often with relatively limited involvement in cannabis use. This study evaluated the factor structure of the MMM in a demographically mixed sample of 600 young adult (18-30 years) frequent (≥ 3 days per week) cannabis users in the Netherlands. Analysis confirmed a five-factor solution, denoting coping, enhancement, social, conformity and expansion motives. Additionally, the original MMM was extended with two items (boredom and habit), which formed a distinct, internally consistent sixth factor labelled routine motives. In a multivariable logistic regression analysis, coping and routine motives showed significant associations with 12-month DSM-IV cannabis dependence. The results suggest general reliability and validity of the MMM in a heterogeneous population of experienced cannabis users.

Lessons from conducting trans-national Internet-mediated participatory research with hidden populations of cannabis cultivators.

BACKGROUND: Internet-mediated research methods are increasingly used to access hidden populations. The International Cannabis Cultivation Questionnaire (ICCQ) is an online survey designed to facilitate international comparisons into the relatively under-researched but increasingly significant phenomenon of domestic cannabis cultivation. The Global Cannabis Cultivation Research Consortium has used the ICCQ to survey over 6000 cannabis cultivators across 11 countries. In this paper, we describe and reflect upon our methodological approach, focusing on the digital and traditional recruitment methods used to access this hidden population and the challenges of working across multiple countries, cultures and languages. METHODS: Descriptive statistics showing eligibility and completion rates and recruitment source by country of residence. RESULTS: Over three quarters of eligible respondents who were presented with the survey were included in the final sample of n=6528. English-speaking countries expended more effort to recruit participants than non-English-speaking countries. The most effective recruitment modes were cannabis websites/groups (33%), Facebook (14%) and news articles (11%). While respondents recruited through news articles were older, growing practice variables were strikingly similar between these main recruitment modes. CONCLUSION: Through this process, we learnt that there are trade-offs between hosting multiple surveys in each country vs. using one integrated database. We also found that although perceived anonymity is routinely assumed to be a benefit of using digital research methodologies, there are significant limits to research participant anonymity in the current era of mass digital surveillance, especially when the target group is particularly concerned about evading law enforcement. Finally, we list a number of specific recommendations for future researchers utilising Internet-mediated approaches to researching hidden populations.