Trends in cannabis use and cannabis-related treatment demand in Switzerland

Transcription

1 Trends in cannabis use and cannabis-related treatment demand in Switzerland Etienne Maffli, Addiction Switzerland, Lausanne TDI and HRDU annual expert meetings, Lisbon, sept

2 Data sources available in Switzerland for assessing cannabis trends General population survey each 5 years since 1992 (Swiss Health Survey) (Continuous general population survey on substance related behaviours (CoRolAR) since 2011) School survey (HBSC) each 4 years since 1986 (sample of 15 year old pupils) Treatment monitoring data since 1997 (voluntary participation) harmonised since 2005 (act-info) (Mortality data: one case related to cannabis since 1995) Police data: offenses against narcotic law (national register, records since 1990)

3 Trend lifetime prevalence and current cannabis use (Swiss Health Survey 1992, 1997, 2002, 2007, 2012) 25% 20% 15% 10% lifetime current use 5% 0% Resident population aged from 15, n ranging between and Current use: using cannabis at least monthly

4 Trend of current cannabis use prevalence (Swiss Health Survey 1992, 1997, 2002, 2007, 2012) 3.0% 2.5% 2.0% 1.5% 1.0% 0.5% 0.0% Resident population aged from 15, n ranging between and Current use: using cannabis at least monthly

5 3.0% Trend of current cannabis use prevalence: respective proportions of age categories (SHS 1992, 1997, 2002, 2007, 2012) 2.5% 2.0% 1.5% 1.0%.5% % Resident population aged from 15, n ranging between and Current use: using cannabis at least monthly

6 3.0% 2.5% 2.0% 1.5% 1.0% 0.5% Trend of current cannabis use prevalence: respective proportions of pseudo cohorts (SHS 1992, 1997, 2002, 2007, 2012) Born around (+-2) 0.0% Resident population aged from 15, n ranging between and Current use: using cannabis at least monthly

7 Age distribution of current cannabis users (SHS 1992, 1997, 2002, 2007, 2012) 35% 30% 25% 20% 15% 10% 5% 0% Resident population aged from 15, n ranging between and Current use: using cannabis at least monthly

8 Overall age distribution of current cannabis use (SHS ) 30% 25% 20% 15% 10% 5% 0% Resident population aged from 15, Total n over all 5 survey waves: Current use: using cannabis at least monthly

9 Conceptual framework for trend interpretation Age effects: age specific attitudes (openness vs. resistance) for experiencing or engaging cannabis use (e.g. attractiveness for risk taking behaviours among teenagers, importance of peer modelling ) Period effects: time-related events or conditions that impact general attitudes towards cannabis use in a given period of time (market availability, changes in regulation, media topics, economical situation ) Cohort effects: common elements of socialisation and experiences shared among people in the same age that impact long lasting attitudes towards cannabis use across time (e.g. punk generation )

10 Offences against narcotic law: notifications related to cannabis use in Switzerland ( ) Number of reports * Source: Swiss Federal Statistical Office *Changes regarding the method of counting

11 50% 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Lifetime prevalence of cannabis use among pupils aged 15 (HBSC 1986, 1994, 1998, 2002, 2006, 2010) boys girls n ranging between 932 and 2552 in this age category

12 Features of treatment data collections Include mostly cases where use is assumed to be harmful and where help is sought for reducing or stopping use. Reflect more the burden carried by the society The threshold for treatment demand is partly shaped by societal norms about deviant behaviours (cases referred by justice) Latency between start of problematic use and first treatment demand Collecting data is often challenging in the care supply (therapeutic, but not always statistical interests)

13 Treatment monitoring act-info ( ): Relative share of primary drugs at intake 90% 80% 70% 60% 50% 40% 30% 20% Cannabis Cocaine Opiates 10% 0% Participating facilities without heroin prescription and gp s Other drugs considered, but not displayed (range all others drugs: 5.4%-10.9%)

14 Treatment monitoring act-info: absolute numbers of admissions by primary drug ( ) Opiates Cocaine Cannabis Absolute numbers of treatment intake in facilities with constant data delivery

15 Cannabis as primary drug: new and all treatments (absolute numbers ) new cases all cases Absolute numbers of treatment intake

16 Frequency of cannabis use before treatment intake (cannabis as primary drug; act-info ) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% no use 1 day/week or less 2-3 days/week 4-6 days/week once daily several times daily

17 Age at treatment intake (cannabis as primary drug; act-info ) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% bellow 15

18 Conclusions The general trend in cannabis use over the last 25 years in Switzerland shows an increase till 2002 followed by a slight drop and stabilisation. Crossed data sources tend to confirm this picture and suggest a period effect around 2002 having led to a maximum attractiveness for cannabis. The age structure over time suggests a high vulnerability for experiencing cannabis in adolescence and youth. Such age effects are known for different kinds of risk-taking behaviours. The development observed in pseudo cohorts suggests that the level of exposure in adolescence and youth seems having a long lasting impact regarding later use.

19 Conclusions The starting time of the epidemic (end of the 60ies) and its following further development seems having reached saturation about 10 years ago, but cohort effects are still impacting the current level. In contrast, treatment data showed an increase in demand till 2010 followed by first signs of stagnation. Factors for this delay compared with use patterns, may be multiple. Some changes in the profile regarding severity of use and regarding age suggest changes in the societal perception of the phenomenon, perhaps since alarming reports on psychiatric comorbidity became published in massmedia.