Triangulating Amsterdam's illicit stimulant use trends by wastewater analysis and recreational drug use monitoring.

Drug consumption estimates are of relevance because of public health effects as well as associated criminal activities. Wastewater analysis of drug residues enables the estimation of drug consumption and drug markets. Short-term and long-term trends of cocaine, MDMA (ecstasy), amphetamine (speed) and methamphetamine (crystal meth), were studied for the city of Amsterdam. MDMA (+41%) and cocaine (+26%) showed significantly higher weekend vs. week consumption, while no differences were observed for the other drugs. The consumption of MDMA, cocaine, amphetamine and methamphetamine significantly increased between 2011 and 2019. Weekly trends emerging from wastewater analyses were supported by qualitative and quantitative data from a recreational drug use monitoring scheme. However, information collected in panel interviews within nightlife networks and surveys among visitors of pubs, clubs and festivals only partially reflected the long term increase in consumption as registered from wastewater analysis. Furthermore, methamphetamine use was not well presented in survey data, panel studies and test service samples, but could be monitored trough wastewater analysis. This illustrates that wastewater analysis can function as an early warning if use and user groups are small or difficult to reach trough other forms of research. All in all, this study illustrates that wastewater-based epidemiology is complementary to research among user groups, and vice versa. These different types of information enable to connect observed trends in total drug consumption to behaviour of users and the social context in which the use takes place as well as validate qualitative signals about (increased) consumption of psychoactive substances. Such a multi angular approach to map the illicit drug situation on local or regional scale can provide valuable information for public health.

Changing Patterns of Substance Use During the Coronavirus Pandemic: Self-Reported Use of Tobacco, Alcohol, Cannabis, and Other Drugs.

As in many other countries worldwide, the coronavirus pandemic prompted the implementation of an "intelligent lockdown" in the spring of 2020 in the Netherlands, including the closure of nightlife venues and cancellation of festivals. Such restrictions and social distancing could particularly affect people who use alcohol or other drugs in recreational settings and give rise to new challenges and additional needs in the field of addiction prevention and care. To monitor changes in substance use and provide services with practical directions for tailored prevention, an anonymous web survey was set up, targeting a convenience sample aged 16 years or older through various social media and other online channels. Between May and October 2020, a total of 6,070 participants completed the survey, mainly adolescents and young adults (16-24 years old). These data were used to explore and describe changing patterns in substance use. Overall results showed declined current use compared to "pre-corona," but mask underlying variation in changing patterns, including discontinued (tobacco 10.4%, alcohol 11.3%, cannabis 16.3%, other drugs 30.4%), decreased (tobacco 23.0%, alcohol 29.1%, cannabis 17.4%, other drugs 20.7%), unchanged (tobacco 30.3%, alcohol 21.2%, cannabis 22.3%, other drugs 17.3%), increased (tobacco 29.6%, alcohol 32.1%, cannabis 32.9%, other drugs 25.3%), and (re)commenced use (tobacco 6.7%, alcohol 6.3%, cannabis 11.1%, other drugs 6.2%). Especially the use of drugs like ecstasy and nitrous oxide was discontinued or decreased due to the lack of social occasions for use. Increased use was associated with coping motives for all substance types. As measures combatting the coronavirus may need to be practiced for some time to come, possibly leading to prolonged changes in substance use with lingering "post-corona" consequences, timely and ongoing monitoring of changing patterns of substance use is vital for informing prevention services within this field.

Visitors of the Dutch drug checking services: Profile and drug use experience.

BACKGROUND: Drug checking services (DCS) provide information about drug content and purity, alongside personalized feedback, to people who use drugs; however, the demographic and drug use characteristics of DCS clients are rarely reported. This paper describes these characteristics for clients of the Dutch DCS, the Drug Information and Monitoring System (DIMS). METHODS: 1,530 participants completed a pen-and-paper questionnaire at one of eight participating DCS in the Netherlands in 2018. RESULTS: The participants were mostly highly educated males in their twenties with no migration background. Experience with drugs prior to coming to the DCS was common. Only 0.7% indicated they had never used any of the twenty drugs studied. 93% of participants reported use of ecstasy or MDMA with an average of 6.3 years since first use. CONCLUSIONS: These results indicate that drug checking can be a valuable tool for public health services as it facilitates access to more difficult-to-reach communities who use drugs. It is unlikely that DCS encourage drug initiation, since almost all people who visit the Dutch DCS already report experience with drugs. However, DCS should be aware that their services might not be easily accessible or attractive to all demographic groups.

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.

A Comparison of Excessive Drinking, Binge Drinking and Alcohol Dependence in Ethnic Minority Groups in the Netherlands: The HELIUS Study.

BACKGROUND: The Dutch multi-ethnic Healthy Life in an Urban Setting study recently showed that alcohol consumption was lower in ethnic minority groups than those of Dutch origin, but that binge drinking in drinkers of Turkish and Moroccan origin was relatively high. The aim of the current study is to examine factors that may contribute to the differences in drinking patterns and how they relate to the relationship between drinking patterns and alcohol dependence (AD) across ethnic groups. METHODS: The rate of last year alcohol use, alcohol use patterns and AD was assessed in 4,635 Dutch, 4,317 Moroccan, 4,036 Turkish, 2,459 Ghanaian, 4,426 African Surinamese and 3,357 South-Asian Surinamese participants (both men and women) born in Amsterdam, the Netherlands. RESULTS: Compared to the Dutch, the prevalence of (regular) drinking is substantially lower in all ethnic minority groups and regular drinkers among most ethnic minority groups have a lower adjusted risk to develop binge drinking and AD than the Dutch. For the prevalence of regular drinking, the ethnic differences are bigger than for the prevalence of current drinking. However, regular drinkers of Moroccan origin have a risk similar to the Dutch to develop binge drinking and AD; a finding that could not be explained by group differences in age, sex, religiosity, perceived discrimination, depression or guilt feelings about drinking. DISCUSSION: The prevalence data show that current drinking is lower and that regular drinking is much lower in ethnic minorities and - with the exception of those of Moroccan origin - ethnic minority regular drinkers also have a significant lower risk to develop binge drinking or AD than regular drinkers of Dutch origin. This implies that the magnitude of problematic alcohol use is substantially smaller in ethnic minorities than in the ethnic Dutch population of Amsterdam. Unfortunately, no explanation was found for the special risk situation of regular drinkers of Moroccan origin.

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.

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.

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.

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.

Local politics and retail cannabis markets: the case of the Dutch coffeeshops.

BACKGROUND: Cannabis coffeeshops are concentrated in specific areas in the Netherlands; close to 80% of Dutch municipalities have no coffeeshops. We investigated why such wide local differences exist. METHODS: Regression analyses were carried out on data regarding the number of coffeeshops per municipality, local council seat distribution and area demographic characteristics. A contrast analysis of municipalities with no/few vs. many coffeeshops was also performed. RESULTS: Whether a town has one or more coffeeshops can be predicted in part by its population size, but more strongly by political composition of the local council. The larger the percentage of progressive councillors, the greater the probability that coffeeshops are allowed. The number of coffeeshops in a town depends primarily on the demand for cannabis (reflected in factors like local population size); it generally has little to do with national-level party political preferences about drug policy. CONCLUSION: Both the demand for coffeeshops and local political preference influence coffeeshop policy in the Netherlands.

How to find non-dependent opiate users: a comparison of sampling methods in a field study of opium and heroin users.

BACKGROUND/AIM: The first aim is to better understand the potentials and limitations of different sampling methods for reaching a specific, rarely studied population of drug users and for persuading them to take part in a multidisciplinary study. The second is to determine the extent to which these different methods reach similar or dissimilar segments of the non-dependent opiate-using population. METHOD: Using ethnographic fieldwork (EFW) and targeted canvassing (TARC; small newspaper advertisements and website announcements), supplemented by snowball referrals, we recruited and interviewed 127 non-dependent opiate users (lifetime prevalence of use 5-100 times; 86.6% had used heroin and 56.7% opium). Average age was 39.0; 66.1% were male and 33.9% female. RESULTS: In addition to opiates, many respondents had wide experience with other illicit drugs. The majority had non-conventional lifestyles. Both EFW and TARC yielded only limited numbers of snowball referrals. EFW requires specific skills, is labour-intensive, thus expensive, but allows unsuitable candidates to be excluded faster. Respondents recruited through EFW were significantly more likely to have experience with opium and various drugs other than opiates. TARC resulted in larger percentages of women and respondents with conventional lifestyles. TARC is less labour-intensive but requires more time for screening candidates; its cost-effectiveness depends on the price of advertising for the recruitment. CONCLUSION: Different methods reach different segments of the population of non-dependent opiate users. It is useful to employ a multi-method approach to reduce selectivity.

Predicting ecstasy use among young people at risk: a prospective study of initially ecstasy-naive subjects.

Our aim is to identify predictors of first-time ecstasy use in a prospective study among young people at risk. As part of the multidisciplinary Netherlands XTC Toxicity Study (NeXT), we monitored 188 subjects aged > or = 18 who were ecstasy-naive at baseline but seemed likely to start taking ecstasy in the near future. After an 11- to 26-month follow-up period, 160 respondents remained (85.1%; mean age 21.0 years, 58.1% females): 65 who took ecstasy at least once (ecstasy users) and 95 non-users. At baseline and four times during follow-up, respondents completed self-report questionnaires. Cox regression analysis was used to examine the effects of baseline respondent characteristics on incident ecstasy use. Development of peer group ecstasy use was analyzed by logistic regression. Intention to use ecstasy, low education, and current weekly cannabis use independently increased the hazard rate for first ecstasy use. Although ecstasy use among peers at baseline was not a predictor, the proportion of ecstasy users with ecstasy-using peers increased markedly during the study. Our results suggest that targeted prevention activities should focus in particular on young people who have strong intentions to take ecstasy, especially if they are also regular smokers of cannabis.

Differential responses to cannabis potency: a typology of users based on self-reported consumption behaviour.

AIMS: To determine whether a classification of cannabis users into different types can help to clarify the relationship between cannabis potency and consumption behaviour, harmful physical effects and psychological dependency. METHODS: A field sample of 388 respondents was recruited who had smoked cannabis at least once in the past month. They were contacted and interviewed in 28 cannabis coffee shops located in five Dutch cities. Data were collected with an assisted self-completion questionnaire. Cluster analysis was performed using the k-means method. FINDINGS: Various ways were observed in which cannabis users in natural settings adjusted their intake to the potency of the drug. Cluster analysis identified three broad types of cannabis users. The strongest high type was the youngest, consumed the highest monthly dose, inhaled higher-potency cannabis more deeply, and scored highest on psychological cannabis dependency. The consistent high type preferred milder cannabis, consumed the lowest monthly dose, and compensated for stronger cannabis by inhaling less deeply and smoking less. The steady quantity type was the oldest, usually smoked alone, consumed an intermediate monthly dose, and did not tend to adjust the depth of inhalation to the potency of the cannabis. The results suggest that this typology might also reflect three successive stages in the careers of continuing cannabis users. CONCLUSIONS: Laboratory studies to assess the effects of higher THC concentrations on external and internal exposure to cannabis should allow for the possibility that the types of users studied can affect the results.

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.