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Bonger Instituut

Publicaties van het Bonger Instituut omvatten o.a. artikelen in internationale peer-reviewed tijdschriften, boekhoofdstukken en wetenschappelijke rapporten.

Recente publicaties

Background: Amphetamine-type stimulants (ATS) are the second most commonly used illicit drugs in Europe and globally. However, there is limited understanding of what shapes patterns of ATS use over the life course. The ATTUNE project “Understanding Pathways to Stimulant Use: a mixed methods examination of the individual, social and cultural factors shaping illicit stimulant use across Europe” aims to fill this gap. Here we report initial findings from the life course chart exercise conducted as part of qualitative interviews with ATS users and nonusers.

Methods: Two hundred seventy-nine in-depth qualitative interviews were conducted with five ATS user groups (current and former dependent users;current and former frequent users;non-frequent users) and one group of exposed non-ATS users in five European countries (Germany, UK, Poland, Netherlands and Czech Republic). As part of the interviews, we used life course charts to capture key life events and substance use histories. Life events were categorised as either positive, neutral or negative, and associated data were analysed systematically to identify differences between user groups. We applied statistical analysis of variance (ANOVA) and analysis of covariance (ANCOVA) to test for group differences.

Results: Out of 3547 life events documented, 1523 life events were categorised as neutral, 1005 life events as positive and 1019 life events as negative. Current and formerly dependent ATS users showed more negative life events for the entire life course after age adjustment. Although some group differences could be attributed to the individuals’ life course prior to first ATS use, most negative life events were associated with periods of ATS usage. A detailed analysis of the specific life domains reveals that dominantly, the social environment was affected by negative life events.

Conclusions: For non-dependent, frequent and non-frequent ATS users, negative life events from the period of ATS use do not become obvious in our analysed data. Besides preventing a pathway into ATS dependency, the aim of an intervention should be to reduce the harm by for example drug testing which offers also the opportunity for interventions to prevent developing a substance use dependency.For the group of dependent ATS users, our study suggests holistic, tailored interventions and specialist treatment services are needed, as a single, simple intervention is unlikely to cover all the life domains affected.

Martens, M-S., Zurhold, H., Rosenkranz , M., O'Donnell , A., Addison, M., Spencer, L., McGovern, W., Gabrhelik, R., Petruzelka, B., Rowicka, M., Liebregts, N., Degkwitz, P., Kaner, E., & Verthein, U. (2020). Using life course charts to assess and compare trajectories of amphetamine type stimulant consumption in different user groups: a cross-sectional study. Harm Reduction Journal, 17, [8].

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; night life 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. Marginalized users scored higher on coping and conformity motives, night life 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.

Benschop, A., Urbán, R., Kapitány-Fövény, M., Van Hout, M. C., Dąbrowska, K., Hearne, E.,Henriques, S., Zsuzsa Kaló, Z., Kamphausen, G.,  Silva, J.P., , Wieczorek, L., Werse, B., Bujalski, M., Korf D.J., & Demetrovics. Z. (2020). Why do people use new psychoactive substances? Development of a new measurement tool in six European countries. Journal of Psychopharmacology.

New psychoactive substances (NPS) continue to be considered as a major public health concern in many European countries. The study was implemented within the framework of a transnational project of six European countries (Germany, Hungary, Ireland, Netherlands, Poland, Portugal). Our aim here is to report on the distinct and differentiating characteristics of marginalised NPS users. Three subgroups of a total of 3023 adult NPS users (socially marginalised, night life, online community) were examined regarding their socio-demographic characteristics, substance use, and external motives towards NPS use. Poland and Hungary reported higher rates of NPS use in comparison to traditional controlled drugs. The external/contextual motives did not play a central role in the background of NPS use, the least important motives were alleged legality and non-detectability of these substances. Marginalised (defined as those accessing low threshold harm reduction services) users’ substance use patterns are different from the other two groups in terms of showing more intense and riskier drug use. The most important variables which contributed to be categorised as a marginalised NPS user were lower level education, being older, having an unfavourable labour market position and using drugs intravenously. Contextual motives did not play a decisive role in being categorised as a marginalised user when drug use pattern was controlled. These identified discriminative features of marginalised drug users should inform policy makers to develop and implement tailor-made interventions targeting this user group to successfully tackle the elevated public health concerns associated with NPS use.

Felvinczi, K., Benschop, A., Urbán, R., Van Hout, M.C., Dąbrowska, K., Hearne., E., Henriques, S., Kaló, Z., Kamphausen, G., Silva, J.P., Wieczorek, Ł., Werse, B., Bujalski, M., Demetrovics, Z., Korf, D.J. (2019). Discriminative Characteristics of Marginalised Novel Psychoactive Users: a Transnational Study. International Journal of Mental Health and Addiction, pp 1-20.


For thousands of years, humans have been using substances that are called ‘drugs’ today, for example to relieve pain, to relax, to gain energy, or in the course of cultural and religious rituals. In search for explanations as to why so many people in the 21st century use drugs, and why in such a wide variety, several macro level factors or drivers need to be addressed.

Chapters in this volume contribute to the understanding of drug use, drug users, drug markets and drug policy in Europe. All the authors work in this field, and are involved in local, national or international research on drug use, drug users or drug dealers. Their research is not carried out in laboratories nor treatment centres. Some of it is predominantly conducted in libraries and archives, but most takes place elsewhere – on the streets, in nightclubs, in private drug-dealing settings. The authors are social scientists from different disciplines – anthropology, criminology, geography, economics, linguistics, psychology, sociology, social psychiatry – and many of them have an interest in, or are specifically oriented to qualitative research methods, including participant observation, informal conversations and in-depth interviews. In the search for explanations as to why particular groups turn to or continue to use certain substances over others, why some people use drugs, why users prefer particular methods of supply, and why current drug policies exists, each of the chapters underline the utmost importance of this book, which captures many of the complexities of how drug use and drug dealing is explained, experienced and often problematised today.

Kaló, Z., Tieberghien, J., Korf, D.J. (Eds.) (2019). Why? Explanations for drug use and drug dealing in social drug research. Lengerich: PABST Science Publishers.

Het bezoeken van een café gaat bijna altijd gepaard met het drinken van alcohol. Amsterdamse cafébezoekers drinken vaak en veel met een gemiddelde van 6 glazen per uitgaansavond. Toch lijken alcoholvrije alternatieven aan te slaan. Andere drugs, met name ecstasy en cocaïne worden ook weleens gebruikt, maar zelden in het café.

Dit zijn enkele opvallende resultaten uit Antenne Amsterdam 2018. Dit jaarlijkse onderzoek van de Hogeschool van Amsterdam en Jellinek brengt al een kwart eeuw het middelengebruik onder jongeren en jongvolwassenen in de hoofdstad in kaart. In 2018 is voor de vijfde maal een survey onder cafébezoekers gehouden. Voor dit onderzoek hebben 540 bezoekers cafés in Amsterdam, met een gemiddelde leeftijd van 26 jaar, een vragenlijst ingevuld en is een uitgaanspanel ondervraagd.

Korf, D.J., Nabben, T., & Benschop, A. (2019). Antenne 2018. Trends in alcohol, tabak en drugs bij jonge Amsterdammers. Amsterdam: Rozenberg publishers



Introduction Amphetamine-type stimulants (ATS) including amphetamine, methylenedioxymethamphetamine/‘ecstasy’, methamphetamine, synthetic cathinones and ‘Ritalin’ are the second most commonly used illicit drugs globally. Yet, there is little evidence on which factors are associated with the development of different patterns of ATS use over the life course. This study aims to examine which individual, social and environmental factors shape different pathways and trajectories of ATS consumption. The study will be conducted in five European countries: Germany, the Netherlands, Poland, Czech Republic and the UK.

Methods and analysis We will use a sequential mixed-methods study design to investigate the multiple factors (familial, social and occupational situation, critical life events, general risk behaviour, mental and physical health, satisfaction with life) that shape individual ATS use pathways. A systematic literature review will be performed to provide an overview of the current academic literature on the topic. In module 1, qualitative semistructured interviews (n=ATS users and non-users) will be conducted to explore individual experiences of, and perspectives on, dynamics of change in stimulant consumption patterns. In module 2, structured questionnaires (n=2000 ATS users and non-users) will be administered via tablet computers to validate and enhance the generalisability of the interview findings. Data integration will take place at two key points. First, during the study, where the findings from the first qualitative interviews will inform the design of the structured questionnaire. Second, at the end of the study, where mixed methods data will be brought together to generate an in-depth, contextualised understanding of the research topic.

Ethics and dissemination The study has been approved by the respective responsible ethics committee in each participating country. Data will be treated confidentially to ensure participants’ anonymity. Findings will be disseminated in peer-reviewed scientific journals, national and international conferences, and in briefings for policy and practice.

Rosenkranz, M., O'Donnell, A., Verthein, U., Zurhold, H., Addisson, M., Liebregts, N., Rowicka, M., Bartak,M., Petruzelka, B., Kaner, E.F.S., & Martens, M. (2019). Understanding pathways to stimulant use: a mixed-methods examination of the individual, social and cultural factors shaping illicit stimulant use across Europe (ATTUNE): study protocol. BMJ Open 2019; 9:e029476. doi: 10.1136/bmjopen-2019-029476

Purpose: The purpose of this paper is to: describe and contextualize the aims and distinctive and common characteristics of cannabis festivals in countries with different cannabis policies; assess characteristics of participants; identify reasons to attend cannabis festivals; explore to which extent cannabis festivals contribute to the social and cultural acceptance of cannabis, as perceived by attendees. Design/methodology/approach: The approach incorporates three methods of data collection in the research design; quantitative research among 1,355 participants, participant observation and interviews with the organizers. Findings: Cannabis festivals in Amsterdam, Berlin, Rome and Athens have common features but also maintain and reproduce local, social and cultural characteristics. Cannabis festivals, as well as their attendees, represent heterogeneous categories. The style of the festival – music festival or march combined with music – affects the main reason for attendance by the participants. In cannabis festivals more similar to music festivals the majority of the respondents attended for entertainment while at the cannabis festivals in the form of a march combined with music the majority attended for protest. Furthermore, increasing age, residency and the high frequency of cannabis use are factors that led the participants to attend for protest. Originality/value: The research on cannabis festivals is limited. This paper not only explores the aims of cannabis festivals in four capital cities of Europe and the characteristics of their attendees including motivations, but also offers interesting insights for understanding the ways in which political and social constructions like cannabis festivals shape attitudes, perception and behaviors around cannabis use.

Skliamis, K. & Korf, D.J. (2019). Cannabis festivals and their attendees in four European cities with different national cannabis policies, International Journal of Event and Festival Management.

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.

Boumparis, N., Loheide-Niesmann, L., Blankers, M., Ebert, D., korf, D.J., D., Schaub, M., Spijkerman, R., Tait, R., J. and Riper, H. (2019) The short- and long-term effects of digital prevention and treatment interventions for cannabis use reduction: A systematic review and meta-analysis. Drug and Alcohol Dependence. 200, 82-94.

The Netherlands has long been considered a leader of progressive drug policy, but it is increasingly being left behind by policy innovations outside Europe. Nonetheless Dutch cities are leading the way towards more progressive and locally adapted cannabis policies. Produced as part of a the "New Approaches in Harm Reduction Policies and Practices" project, this Country Report seeks to understand the drivers of Dutch cannabis policy today, and the possibilities for its future. The project is a joint project of the Transnational Institute (TNI), based in the Netherlands ICEERS (Spain), Forum Droghe (Italy) and Diogenis (Greece).

Korf, D.J. (2019). Cannabis Regulation in Europe: Country Report Netherlands. Amsterdam: Transnational Institute.

Use of new psychoactive substances (NPS) across Europe remains a public health challenge. The study describes potentials and limitations of methods in a transnational survey of recent marginalised, nightlife and online community NPS users in Germany, Hungary, Ireland, the Netherlands, Poland and Portugal (n = 3023). In terms of demographic profile, drug use history and type of NPS, different methods reached different segments of the NPS-using population. Last year use of different NPS varied across countries and groups. Respondents used NPS in a variety of settings, with public spaces most common in the marginalised group. The study suggests that prevalence rates can reveal a picture of the NPS market that significantly deviates from what law enforcement seizures indicate. Outreach in nightlife settings and peer education are recommended to inform users about health risks and to improve access to drug services and care.

Korf, D. J., Benschop, A., Wernse, B., Kamphausen, G., Felvinczi, K., Dabrowska, K., Hernriques, S., Nabben, A. L. W. M., Wieczorek, L., Bujalski, M., Kalo, Z., Hearne, . E. & van Hout, M. C. (2019) International Journal of Mental Health and Addiction. () 1-18


Aanleiding voor dit onderzoek was de constatering dat de groei in het aantal aangepakte criminele samenwerkingsverbanden (csv’s) niet terug te zien was in de ontwikkeling van het aantal vrijheidsstraffen. Om de georganiseerde misdaad terug te dringen werd in 2012 tussen de (toen nog) Minister van Veiligheid en Justitie, de politie en het OM afgesproken dat er meer csv’s zouden moeten worden aangepakt: in 2014 twee keer zoveel als in 2009. Probleemstelling: Welke verklaring(en) ligt/liggen ten grondslag aan het achterblijven/ uitblijven van een stijging in het aantal strafopleggingen bij het aantal door het OM gerapporteerde aangepakte csv’s over de periode 2009-2015?

Korf, D.J., Luijk, S.J., Meijer, M.E. de (2019). Criminele samenwerkingsverbanden. Ontwikkelingen in aanpak en duiding van effectiviteit. Amsterdam: Rozenberg Publishers


Given the multiple ways of regulations and market situations for new psychoactive substances (NPS), it is of interest how NPS users procure their drugs in different countries as well as in different user groups. Data comes from a face-to-face and online survey conducted in six EU countries, covering three groups of current (12-month) adult NPS users: (1) socially marginalized, (2) users in night life, and (3) users in online communities. While the supply situation differed considerably between countries, friends were the most prevalent source for buying, followed by online shops and private dealers. Marginalized users were more likely to buy from dealers, while online respondents showed the highest rates for buying online. While buying NPS from online or offline shops was relatively prevalent, we also found high rates for social supply and buying from dealers. A considerable part of this market may be classified as “social online supply,” with private suppliers procuring their drugs online. The market features among marginalized users resemble more those of illicit drug markets than those for other NPS users.

Wernse, B., Benschop, A., Kamphausen, G., van Hout, M. C., Henriques, S., Paula Silva, J., Dąbrowska, K., Wieczorek, L., Bujalski, M., Felvinczi, K., & Korf, D. J. (2018). Sharing, Group-Buying, Social Supply, Offline and Online Dealers: how Users in a Sample from Six European Countries Procure New Psychoactive Substances (NPS). International Journal of Mental Health and Addiction, 1-15.


Illegal drug use is common across Europe—and around the world. Drug use is accompanied by drug markets, which emerge and evolve as an inevitable response to demand. Drug policies are enacted in response to these, whether aimed at eliminating use and supply, or minimising the harms related to them. These are the core components of the ‘drug problem’. While the drug problem is a global phenomenon, the way its components manifest themselves vary widely. The prevalence of use of different drugs changes over time and across different places. The characteristics of drug cultures and drug markets differ by geographical, social and cultural context. Drug policies, while broadly governed by global drug treaties, are shaped by local and national politics and designed to respond to local and national concerns. Drug use, drug markets and drug policies are, ultimately, located in specific geographical, cultural and temporal contexts. As the drug problem varies across place, space and time, so understanding drug issues must take account of these dimensions. In this book, we bring together contributors from across Europe, each focussing on different aspects of the drug problem in different countries and different contexts. Each chapter contributes important knowledge about specific aspects and examples of the drug problem. Together, they provide even greater insights into the relationships between drug use, markets and policy, and their situation in place, space and time.

Potter, G.R., Fountain, J., and Korf, D.J. (eds). (2018) Place, space and time in European drug use, markets and policy. Lengerich: PABST Science Publishers.


Life history interviews are a commonly used method in qualitative drug research, but the use of timelines in these interviews remains limited. This chapter explores and discusses the use, pros and cons of timelines as a method employed in two qualitative studies on substance use trajectories. It shows how, by combining in-depth interviews and timelines, the interview can become an interactive analytical process in the search for relationships between life course/life events and patterns of substance use and non-use, and also the underlying processes of substance use pathways. Timelines can support memory recall for the interviewee, and, particularly in studies of drug use trajectories, they can enhance the researcher's understanding of the relationships between these trajectories and the life course more quickly and more deeply than if an interview alone is used.

Liebregts, N. (2018). Nuts and bolts of timelines in qualitative drug research. In: Potter, G.R., Fountain, J., and Korf, D.J. (eds). (2018) Place, space and time in European drug use, markets and policy. Lengerich: PABST Science Publishers.


In Antenne 2017 worden trends in het Amsterdamse uitgaansleven en de daarmee samenhangende ontwikkelingen in middelengebruik beschreven aan de hand van een panelstudie en een survey onder clubbers en festivalgangers. Het middelenrepertoire in de trendsettende netwerken en scenes van het uitgaanspanel kan aanzienlijk verschillen. Ecstasy is (na alcohol) het belangrijkste uitgaansmiddel. Het gebruik van stimulantia (ecstasy, cocaïne en amfetamine) is onderling inwisselbaar. De keuze voor een van deze middelen hangt samen met het (feest)moment en de setting. Ruim 600 uitgaanders (clubbers en festivalgangers) deden mee aan een survey. Tabak, alcohol, cannabis, lachgas en ecstasy zijn de middelen die zij het meest gebruiken. Cocaïne, amfetamine, ketamine, ghb en 4-fa worden ook gebruikt, maar wat minder. Onder uitgaanders is er een bescheiden belangstelling voor Nieuwe Psychoactieve Stoffen (NPS). Naast uitgaanders gaat Antenne 2017 over kwetsbare buurtjongeren in Amsterdamse volkswijken. Voor deze jongeren zijn vooral alcohol, cannabis en lachgas aantrekkelijke middelen.

Nabben, T., Luijk, S.J., & Korf, D.J. (2018) Antenne 2017.​ Trends in alcohol, tabak en drugs bij jonge Amsterdammers. Amsterdam: Rozenberg Publishers. 


De Wet OM-afdoening geeft de officier van justitie de bevoegdheid om strafbeschikkingen uit te vaardigen in het geval van overtredingen en misdrijven die met maximaal zes jaar gevangenisstraf worden bestraft. De strafbeschikking wordt opgelegd zonder tussenkomst van de rechter. In opdracht van het ministerie van Veiligheid en Justitie voerde de afdeling Strafrecht in samenwerking met het Bonger Instituut een evaluatieonderzoek uit naar de Wet OM-afdoening. Het doel van de evaluatie was om te beschrijven of de wet conform de doelstellingen van de wetgever wordt uitgevoerd en welke knelpunten zich in de praktijk voordoen. Een belangrijk onderdeel van dit onderzoek bestond uit het krijgen van meer inzicht in de veronderstelde werking van de Wet OM-afdoening. Daarnaast is ook de daadwerkelijke werking van de wet onderzocht en is beoordeeld in hoeverre de praktijk afwijkt van de doelstellingen en de verwachtingen van de wetgever.


Abels, D., Benschop, A., Blom, T., Coster van Voorhout, J., Korf, D.J., Liebregts, N., & Vriend, K. (2018). Evaluatie Wet OM-Afdoening. Amsterdam: Rozenberg Publishers.


In 2017 is de methodiek van Antenne (die al vijfentwintig jaar in Amsterdam wordt gebruikt) voor het eerst ook toegepast in een andere regio, namelijk Gooi en Vechtstreek. Om zicht te krijgen op het gebruik van tabak, alcohol en andere drugs onder jongeren en jongvolwassenen in de regio is gebruikgemaakt van kwalitatieve en kwantitatieve methoden. Door middel van een focusgroep met professionals is een kwalitatieve inventarisatie gemaakt van het middelengebruik onder groepen jongeren in Gooi en Vechtstreek. Om precieze cijfers te kunnen leveren over het middelengebruik is een survey onder uitgaanders gehouden. Ook zijn gegevens van de drugstestservice van Jellinek Preventie Gooi en Vechtstreek geanalyseerd. Tabak, alcohol en cannabis zijn de middelen die uitgaanders het meest gebruiken. Het gebruik van ecstasy, amfetamine en cocaïne ligt een stuk lager. Voor, tijdens en na het uitgaan in de feestcafés en clubs wordt er vooral gedronken en gerookt.  


Luijk S.J., Nabben T. & Korf D.J. (2018) Antenne Gooi en Vechtstreek 2017. Het gebruik van alcohol, tabak en drugs onder jongeren en jongvolwassenen in de regio. Amsterdam: Bonger Instituut voor Criminologie.


Een aangifte van een strafbaar feit door een burger leidt vaak niet tot een strafvervolging. De officier van justitie kan beslissen dat de zaak niet aan de rechter wordt voorgelegd, maar wordt geseponeerd. Tegen deze beslissing kan de belanghebbende zich op grond van artikel 12 Wetboek van Strafvordering beklagen bij het gerechtshof. Dit boek bevat een verslag van een onderzoek naar de praktijk van deze beklagprocedure en de kwaliteit van het werk van het Openbaar Ministerie. 
De centrale vraag in het onderzoek is of het werk van het Openbaar Ministerie in de beklagprocedure beantwoordt aan de kwaliteitseisen die daaraan mogen worden gesteld. Relevante informatie is verkregen door een kwantitatieve analyse van beklagzaken over de jaren 2010-2014, een uitvoerig dossieronderzoek en interviews met functionarissen die betrokken zijn bij de afhandeling van beklagzaken.

Benschop, A., Korf, D.J., De Meijer, M.E., Simmelink, J.B.H.M., Willemsen, A.W.A. (2018). Beklag over niet vervolgen: Hoe gaat het Openbaar Ministerie om met art. 12 Sv-zaken? Den Haag: Boom Juridisch.


Voor dit Bonger Bulletin onderzochten we in hoeverre legale status, prijs en beschikbaarheid een rol speelden in het gebruik van 4-FA voordat het middel in mei 2017 werd opgenomen in de Opiumwet.

Benschop, A. & Korf, D.J. (2018). Is te verwachten dat de strafbaarstelling van 4-FA van invloed is op gebruik? Amsterdam: Bonger Instituut.


In dit rapport wordt verslag gedaan van een nadere verkenning van lachgasgebruik in Nederland. Daarvoor is in 2017 onderzoek gedaan, deels kwalitatief (interviews met professionals en veldonderzoek onder gebruikers en naar de verkoop van lachgas) en deels kwantitatief (analyse van gegevens over lachgasgebruik uit recente surveys onder verschillende bevolkingsgroepen en een vervolgsurvey onder uitgaanders die lachgas gebruiken).

Nabben, T., Van der Pol, P. & Korf, D.J. (2017). Roes met een luchtje. Gebruik, gebruikers en markt van lachgas. Amsterdam: Rozenberg Publishers.


4-Fluoramfetamine (4-FA) is een middel dat in korte tijd opkwam en veel stof deed opwaaien. Was ecstasy al jaren onbetwist nummer 1 van de uitgaansdrugs onder festival- en clubgangers, met het verschijnen van 4-FA op de Nederlandse drugsmarkt leek de concurrentie te zijn ingezet. Bestaande monitoringinstrumenten signaleerden in afgelopen jaren niet alleen een toenemende populariteit van 4-FA maar ook (in het kielzog hiervan) een toenemend aantal gezondheidsincidenten, die een opmaat waren voor een verbod op 25 mei 2017. Deze verkenning brengt het gebruik, de gebruikers en de ervaren gezondheidseffecten van 4-FA nader in beeld om preventie, beleid en onderzoek verder invulling te geven.

Van der Pol, P., Nijkamp, L., Nabben, T. & Van Laar, M. (2017). 4-FA. 4-Fluoramfetamine: gebruikers en gebruik in beeld. Utrecht/Amsterdam: Trimbos-instituut & Bonger Instituut voor Criminologie.


Het eindverslag van de NPS-t studie geeft de resultaten weer van de survey onder meer dan 3.000 NPS-gebruikers uit 6 landen. Resultaten omvatten gebruikspatronen, gebruikersprofielen, aanschaf, marktdynamiek en preventie. Dit rapport belicht de verscheidenheid in typen NPS-gebruikers en tussen landen.

Benschop, A., Bujalski, M., Dabrowska, K., Demetrovics, Z., Egger, D., Felinczi, K., Henriques, S., Kalo, Z., Kamphausen, G., Korf, D.J., Nabben, T., Silva, J.P., Van Hout, M.C., Werse, B., Wells, J., Wieczorek, L. & Wouters, M. (2017). New Psychoactive Substances: transnational project on different user groups, user characteristics, extent and patterns of use, market dynamics, and best practices in prevention. NPS-transnational Project (HOME/2014/JDRU/AG/DRUG/7077).


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.

Skliamis, K. & Korf, D.J. (2017). An Exploratory Study of Cannabis Festivals and Their Attendees in Two European Cities: Amsterdam and Berlin. Journal of Psychoactive Drugs 00(0): 1-9.

[DOI: 10.1080/02791072.2017.1380869] 


By tradition, the human trafficking discourse focuses on cross-border sex trafficking from impoverished countries to countries with a high standard of living. This article explores whether identified trafficking in the Netherlands corresponds to this. We introduce a model that identifies all possible trafficking situations, and with this, intends to prevent tunnel vision and identify blind spots. Subsequently, we analyze 768 trafficking cases identified by the Dutch Public Prosecution Service (2008-2012) and categorize each case according to our model: by form of exploitation and route of trafficking. The data show that (near-)domestic sex trafficking where victims are not pushed out of impoverished countries, but are recruited on native (or neighboring) soil, is the human trafficking situation most commonly identified.

Kragten-Heerdink, S.L.J., Dettmeijer-Vermeulen, C.E. & Korf, D.J. (2017). More Than Just “Pushing and Pulling”: Conceptualizing Identified Human Trafficking in the Netherlands. Crime & Delinquency 00(0): 1-25.

[DOI: 10.1177/0011128717728503]


Aims: To evaluate the consequences of criminalising khat, with a focus on the changes in law enforcement and the use, availability, price and quality of khat in the Netherlands. Methods: Mixed methods, including law enforcement data, expert interviews, focus group interviews with members of the Somali community, and a survey among 168 current (last month) khat users. Findings: Soon after the law changed (early in 2013), and khat had become an illicit drug, much of the khat imported from Africa was confiscated at Schiphol International Airport and users found it more difficult to obtain fresh khat leaves. About two years after the ban had been implemented, the price of fresh khat at user lavel had increased tenfold on average, and much of it was of poorer quality (e.g. sold in dried or powdered form). Conclusion: Criminalisation of khat in the Netherlands had substantial consequences for the distribution chain (transcontinental import by air) and there was a lach of alternative transportation routes that could supply users with fresh khat. It is highly likely that the total number of Somali khat users in the Netherlands dropped, but that the proportion of dependent and poor, "problem users" increased.

Nabben, T. & Korf, D.J. (2017) Consequences of criminalisation: the Dutch khat market before and after the ban. Drugs: Education, Prevention and Policy 24(4): 332-339.

[DOI: 10.1080/09687637.2017.1338669]



Korf, D.J., O'Gorman, A. & Werse, B. (2017) The European Society for Social Drug Research: a reflection on research trends over time. Drugs: Education, Prevention and Policy 24(4): 321-323.

[DOI: 10.1080/09687637.2017.1346061]


In Nederland wordt de verkoop van cannabis in coffeeshops gedoogd als voldaan is aan bepaalde criteria. In 2012 kwamen er twee gedoogcriteria bij: het besloten club- en het ingezetenencriterium (de 'wietpas'). Gepland was een fasegewijze invoering: eerst in het zuiden, later in de rest van het land. Dit bood de mogelijkheid tot een natuurlijk experiment. In een experimentele groep van zeven gemeenten in het zuiden en een vergelijkingsgroep in de rest van het land zijn voor- en nametingen verricht van de ervaren overlast rond coffeeshops, het drugstoerisme, het aantal bezoeken aan coffeeshops en de omvang van de illegale gebruikersmarkt. Hierin traden na de implementatie van de nieuwe criteria substantiële veranderingen op in de experimentele groep. Initiële verschillen tussen de twee groepen en uiteenlopende lokale implementatie maakten het echter problematisch te concluderen dat dit effecten waren van de nieuwe criteria. In dit artikel wordt nu onderzocht of de gevonden veranderingen niet toch causaal toegeschreven kunnen worden aan de nieuwe criteria. De conclusie is dat de onderzoeksopzet dat ondanks de methodologische manco's toelaat en dat de veranderingen werden veroorzaakt door de nieuwe criteria.

Van Ooyen-Houben, M.M.J., Bieleman, B., Korf, D.J., De Witte, K. (2017) Het besloten club- en het ingezetenencriterium voor coffeeshops: Een natuurlijk experiment. Tijdschrift voor Criminologie 59(1-2): 10-29.

[DOI: 10.5553/TvC/0165182X2017059102002​]