The development of patterns of cocaine use: A 5 year follow-up study of 111 experienced cocaine and crack users in Antwerp (Belgium)

Research Period

1 January 2002 - 31 December 2004


Fund for Scientific Research



Key Words

Experienced cocaine and crack users, informal control mechanisms, dynamic patterns of drug use, ethnographic follow-up design


The Original Study

From January 1st 1996 to December 31st 1998 the National Fund for Scientific Re-search supplied a grant for a research project titled 'Cocaine and crack use in Ant-werp: a criminological and ethnographic study of informal control mechanisms in deviant and non-deviant subcultures' (grant No. G.0197-96).

The general focus of the original study was the study of cocaine and crack use in the metropolitan area of Antwerp (a major European port, with appr. 800.000 inhabitants). We wanted to know whether there are informal rules and control mechanisms that are developed by drug users to reduce drug-related harm and to assure non-problematic use of illegal drugs. Are there circles of drug users where informal conduct rules and sanction systems help to keep drug use under control, i.e. non-problematical? More particularly we were interested in possible discrepancies bet-ween those informal mechanisms of self-regulation and the formal control policy of the (Belgian) state. We also wanted to check which psychological, social and economic factors contribute to drug-related harm. Are these factors really drug-related or related with some (sub)cultures) or with official drug policy? Furthermore, we wanted to gain insight in the perspectives and self-understanding of the cocaine users themselves (the insiders' view), and to understand the diverse 'webs of significance and meaning' that they themselves have woven. Finally we also wanted to collect epide-miological data on cocaine use in Antwerp. Especially regarding crack use, there is -despite crack-related 'scares' in the media- little scientific research done. The study was also set up to gain more insight in the nature and prevalence of cocaine use in different layers and subgroups of the general population.

Eventually, through participant observation (ethnographic fieldwork from August 1996 to May 1997) and snowball sampling a sample of 111 experienced cocaine and crack users from the metropolitan area of Antwerp was obtained. Sample inclusion criteria were a minimum lifetime experience of 25 instances of cocaine, not having been found guilty of a felony, and not having been in any drug treatment program. These respondents were interviewed twice (with a semi-structured questionnaire and with an open in-depth interview). The study yielded empirical data regarding the initiation into cocaine use, the level of use through time, periods of abstinence, routes of ingestion, combinational use with other drugs, the purchase of cocaine, the role of set and setting factors, the (subjective) advantages and disadvantages of cocaine use, the (subjective) effects of cocaine, the quality and purity of cocaine, craving, effect on relationships and work, etc. The results of the Antwerp sample were consistently compared with all available data from comparable community studies of cocaine users in other European and American cities (San Francisco, Toronto, Amsterdam, Rotterdam, Barcelona, Turin, Miami) and countries (Scotland and Australia).

The Aim of this Follow-Up Study

The aim of this new research proposal is to have a follow-up study of the original sample of 111 experienced cocaine users. As in the original study we want to gain more insight in the perception and self-understanding of cocaine users, and to comprehend their behavior from 'the native's point of view'. We want to describe a sam-ple of cocaine users from within their culture rather than from outside it, and to present their world as they see it. This research project will study different drug subcultures and their subjective interpretation systems in order to clarify possible confusions of tongue between policy makers, police and treatment actors and drug users themselves. Secondly, we want to gather more data on informal mechanisms and forms of self-control that are developed and adapted by drug users to reduce drug-related harms. How extensive is the users' knowledge and user lore regarding the use of the so-called 'hard' drug cocaine, and what lessons can be drawn from it for poten-tial harm reduction efforts? And thirdly, we want to gain more insight in the nature and prevalence of cocaine use in different layers and subgroups of the general population.

One of the most important conclusions of the original cocaine study was that a large majority of the respondents never seemed to lose control over their drug use. Yet, a lot of negative effects of cocaine were reported. The higher the level of use during their period of heaviest use, the more negative effects were experienced. Maybe that is the reason why only 5.4% of the respondents were at a high level of use (i.e. more than 2.5 grams per week) at the moment of interview, although almost half of the sample (49.5%) reached a high level of use during the period of heaviest use. The most frequently reported patterns of use were 'varying, with temporary peaks of of intensive use and periods of little or no use at all' and 'first gradually more, and after a peak period gradually less'. The average duration of cocaine use careers in the sample was 6 years.

The most important aim (and added scientific value) of this follow-up project is to study the development of patterns of use among the original respondents since they were interviewed at the end of 1996 or the beginning of 1997. In 2002-2003 these respondents will have been using for 11 years (average). The study clearly has a longitudinal character. More specifically we want to know whether some of the respondents from the original study have developed patterns of problema-tical drug use, and if so, which problems were experienced by which proportion of the sample. It is possible that the degree of self-control the 111 experienced cocaine users in Antwerp have demonstrated in the 1996-1997 study, has changed (or diminished) under the influence of a much longer exposure to cocaine.

We are also interested in asking test-retest questions regarding the use of cocaine and other drugs by the respondents. Those questions could teach us something about the reliability of self-report data, a theme that recurrently gets attention in the drug literature.


The researcher makes use of participant observation in the Antwerp nightlife scene to re-establish contacts with key-informants and former respondents, and to prepare the more formal interview situation. This open-focus ethnographic method does not only serve to resuscitate confidential relationships with former respondents, but also to gain more insight in the self-understanding of drug users.

Other respondents are being retraced using the chain referrals that were realized in the original study. Every retraced respondent is interviewed with a slightly modified questionnaire (compared to the one used in the original study). The questionnaire is set up in such a way that comparison with other cocaine studies is feasible to a certain extent.

Valorisation: publications and lectures

  • DECORTE, T. & SLOCK, S. (2005), The Taming of Cocaine II. Brussel: VUB Press.
  • DECORTE, T. (2005), Cocaïne en crack in Antwerpen. V.A.D.-Berichten, 3.
  • CAMBRE, B., DECLERCQ, A. & DECORTE, T. (2005), Evaluating research by returning to the field: a critical inquiry, Paper presented at the First International Congress of Qualitative Inquiry, University of Illinois, Urbana-Champaign, 5-7 mei 2005.
  • DECORTE, T. (2005), Cocaïne en crack in Antwerpen (1997-2003), Nieuwsbrief Algemeen Welzijnswerk, 91, 36-39.
  • SLOCK , S. & DECORTE, T. (2004), Dynamic patterns of cocaine and crack use. Results of 6-year follow-up study of 77 cocaine and crack users in Antwerp. Presentation at the 15th ESSD Conference, München (Duitsland), 13-15 Oktober 2004.
  • DECORTE, T. (2004), Crack use in Antwerp (1996-2003): facts and myths among users. Paper presented at the 15th International Conference on the Reduction of Drug-Related Harm, Melbourne, (Australia), 20-24 April 2004.
  • DECORTE, T. & SLOCK, S. (2004), Dynamic patterns of cocaine and crack use: 6-year follow-up study of 77 cocaine and crack users in Antwerp (Belgium). Poster presentation at the 15th International Conference on the Reduction of Drug-Related Harm, Melbourne (Australia), 20-24 April 2004.
  • DECORTE, T. (2004), Cocaine and crack use in Belgium. Presentation at the International AGIS Conference 'Building a knowledge-sharing based strategy to prevent and reduce drug related crime and other social problems, particularly in relation to the increasing phenomenon of the misuse of cocaine in urban areas', The Hodson Bay Hotel, Athlone (Ierland), 3-4 maart 2004.
  • SLOCK, S. (2004), Follow-up studie naar cocaïnegebruikers: een evenwichtsoefening tussen creativiteit en deontologie bij het opsporen van respondenten na zes jaar, Kwalon, 9(3), 22-26.
  • SLOCK, S. & DECORTE, T. (2002), Longitudinal drug research: some methodological issues. Presentation at the 13th ESSD Conference, Helsinki (Finland), 26-28 September 2002.