Improving Mental Health by Sharing Knowledge Estimating cannabis consumption in seven EU countries by differentiating different user groups Margriet van Laar 1, Tom Frijns 1, Franz Trautmann 1, Linda Lombi 2 1 Trimbos institute, 2 University of Bologna ISSDP, May 15-17, 2013 Bogota, Colombia
Background Prior estimates of cannabis market (demand): Little consideration of differences in consumption patterns between cannabis users EU Drugs markets study I* "Light" versus "heavy"users Extrapolation of data on consumption patterns from few (US) studies to different EU MS Second market study commissioned by EC * Kilmer & Pacula (2009). In: Reuter & Trautmann (2009) 2
Objectives a) To describe characteristics of different types of cannabis users and their consumption patterns b) To describe the availability of cannabis to different types of users c) To estimate the amount of cannabis consumed per user type (and at country level) d) To compare these aspects (a,b, c) in seven EU Member States: Bulgaria, Italy, Netherlands, Czech Republic, Portugal, United Kingdom (England & Wales), Sweden 3
Methods Web survey in spring 2012 www.drugmarket.eu Inclusion criterion: Any use of cannabis, cocaine, ecstasy and/or amphetamine in the past 12 months Age selection (15-64 years) A total of 9,039 'eligible' questionnaires, including 4,126 for cannabis 4
Contents of web survey Cannabis use and typology of users Demographics (age, gender, work status etc.) Characteristics of cannabis use (number of use days, number of units per day, amount of cannabis per unit, mixing tobacco, preference hash/marihuana etc.) Circumstances of cannabis use (when, where, with whom, sharing) Problematic cannabis use (6-item CAST) Availability of cannabis Sources and buying behavior (where obtaining, how often, how much, other drugs available, prices) Ease of obtaining cannabis (perceived availability, time to obtain cannabis) 5
Assessment of the amount (gram) of cannabis per unit A (0.05 gram) C (0.2 gram) Answer categories 1. Less than A 2. A 3. between A and B 4. B 5. Between B and C B (0.1 gram) D (0.3 gram) 6. C 7. Between C and D 8. D 9. More than D 6
Classification of users Type of user 1. Infrequent users or chippers Definition People using cannabis on less than 11 days in the past year ( less than once a month) 2. Occasional users People using cannabis on 11-50 days ( less than once a week but at least once a month) 3. Regular users People using cannabis on 51-251 days ( once a week and more than once a week, but not daily) 4. Intensive users People using cannabis on more than 251 days ( 'daily or almost daily') 5. Problem users Use in the past 12 months and having a score of 7 (moderate dependence) or score 12 (severe dependence) according to the CAST 7
Number of users per user group 1000 900 800 788 CHIPPERS 700 600 OCCASIONAL USERS INTENSIVE USERS 500 REGULAR USERS Almost daily Daily 400 339 349 370 Regular 1 Regular 2 336 366 300 200 257 183 219 217 241 257 100 0 1-5 days 6-10 days 11-20 days 21-50 days 51-80 days 81-100 days 101-150 days 151-200 days 201-250 days 251-300 days 301-350 days >350 days 8
Type of unit BG CZ IT NL PT SE UK Joint 95% 63% 93% 93% 95% 76% 75% Chillum/dry pipe 3% 30% 3% 3% 2% 14% 13% Water pipe 1% 4% 3% 3% 2% 7% 9% Food 1% 0% 0% 2% 1% 2% 2% Beverage 1% 2% 0% 0% 0% 0% 0% Czech Republic: pipes: 11% of the chippers up to 45% of the intensive users gebruikers 9
Cannabis: pure or mixed with tobacco 10
Preference for hash or marihuana 11
Number of units per use day (meand and median) 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Chipper Occasional Regular Intensive Mean Median 12
Number of units per use day 13
Amount of cannabis (gram) per unit 14
Amount (gram) of cannabis consumed on a typical use day by 4-level (upper panel) or 6-level user group (lower panel) 15
Annual consumption per type of user (6 levels) 600 500 400 300 200 100 0 Chipper Occasional Modest regular Frequent regular Almost daily Daily Mean 1.1 9.7 48.1 150.1 274.4 510.2 Median.6 5.3 33.9 105.3 200.6 423.2 16
Annual consumption (gram) among intensieve users by Member State 17
Cannabis Abuse Sreening Test (CAST) average score per user type 18
Estimating consumption at country level Grams of cannabis per year per user group Number of users per user group (from population surveys) Number of users in past year and past month Frequency of use in past month x Multiplying by twelve may result in overestimation Adding estimates of consumption of cannabis among problem drug users (heroin, cocaine, amphetamine) 19
Number of cannabis users and proportion per user group BG CZ IT NL PT SE E& W Past year prevalence (%) Number (x million) 2.7% 15.3% (14.3%) 7.0% 3.6% 2.8% 6.8% (2008) (2008) 2008 (2009) (2007) (2010) (2010/20 11) 0.14 1.13 8.1 0.78 0.26 0.17 2.8 % Chippers 64% 52% 41% 44% 37% 66% 54% % Occasional 17% 20% 37% 15% 13% 15% 17% % Regular 12% 22% 12% 25% 25% 14% 19% % Intensive 7% 6% 10% 17% 25% 5% 9% 20
Amount (ton) of cannabis consumed per user group (per year and country) Amount (tons) BG CZ IT NL PT SE E&W Low 2.6 27.2 383.2 44.1 12.7 5.5 96.1 High 5.2 51.3 480.1 69.4 26.3 8.2 221.0 Average/best* 3.8 33.4 384.3 48.5 17.4 5.8 133.8 % Chippers 2% 2% 1% <1% 1% 2% 1% % Occasional 3% 6% 5% 1% 2% 4% 2% % Regular 18% 37% 23% 21% 30% 37% 20% % Intensive 77% 55% 71% 77% 68% 57% 77% Amount used by problem drug users 0.2-0.4 2.4 n.a. 1.4? 2.0 18-34 * 5% Trimmed mean of annual consumption per user group 21
Conclusions The more frequent cannabis is used, the higher the number of units per day and the more cannabis per unit Consumption patterns show high degree of consistency across user groups, but variation between countries Last month users do not consume each month (the same amount) Smallest user group is responsible for the biggest market share Low frequency users (< once a week) contribute marginally to the overall cannabis consumption per country 22
Reliability of photo card method? Sharing of joints? Some remarks Representativeness of samples (e.g. low internet penetration in some countries) Underreporting and undercoverage of (user populations missed?) Changes and differences in population survey methods 23