Problem cannabis use: what is it and how to assess it?

François Beck

National Institute for Prevention and Health Education (INPES).

Laboratory “Psychotrops, Mental Health and Society” (CESAMES), National Scientific Research Center (CNRS) and

National Institute of Health and Medical Research (INSERM)

Plan

• Why measuring problem cannabis use?

• What do we need to measure?

• how to measure Problem cannabis use?

Expérimentation de cannabis 1995(en %)

1-10 (13)11-20 (6)21-30 (1)31-40 (2)nc (23)

Cannabis lifetime prevalence at age 16 European comparisons : 1995

So

urc

e :

ES

PA

D 1

99

5,

CA

N

1995

Expérimentation de cannabis 1995(en %)

1-10 (13)11-20 (6)21-30 (1)31-40 (2)nc (23)

Expérimentation de cannabis 1999(en %)

1-10 (5)11-20 (10)21-30 (4)31-40 (4)NC (22)

Cannabis lifetime prevalence at age 16 European comparisons : 1995 and 1999

So

urc

es

: E

SP

AD

19

95

et

19

99

, C

AN

19991995

European trends in cannabis last year prevalence among 15-34 years old

Increasing treatment demand for cannabis: Percent of new clients admitted to treatment for cannnabis as main drug in since the late 90’s in France (velvet)

Répartition des patients suivant le produit n°1 à l'origine de la prise en charge ou posant le plus de problèmes (en %)

6,1% 7,4% 6,8% 7,9% 9,1% 8,3%

16,1%19,6% 21,8% 20,6%

25,0% 29,3%28,5%

54,6% 48,2% 47,1% 47,4%43,1%

41,4% 37,9%

10,8%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

1998 1999 2000 2001 2002 2003 2004

Rapports d'activité des CSST, DGS/OFDT

Autres

Méthadone.,BHD

Médpsychotropes

Amphét.,ecstasy

Cocaïne etcrack

Opiacés

Cannabis

Alcool

Concepts

• Problematic cannabis use general definition:– use leading to negative consequences on a social or health

level, both for the individual user and the larger community

• Several standardised grids (DSM4, ICD10) for several concepts :– Abuse (DSM4)

– Harmful use (ICD10)

– Physiological dependence (tolerance and withdrawal)

– Psychological dependence

Concepts and their adaptation

• Measuring problematic cannabis use requires:– Setting criteria to define cannabis problem use– Developing questions that can be used to diagnose whether

a respondent conforms to these criteria– Designing a questionnaire that adequately reflects the

criteria defining problematic use, – Ensuring that responses are accurate, valid and actionable– Measuring the quality of the screening test:

• comparing the screening test with the reference test • assessing the quality of the screening test in a clinical situation

where a practitioner’s diagnosis can be compared with the result of the test

From concepts to screening tests: difficulties and criticism

• Some criteria have been criticised, for example:– Criterion 7 of the DSM-IV: Continued using cannabis despite knowing

it caused significant problems– Spending a great deal of time around the substance might, for instance,

be confounded by the level of legality of the drug– Feeling of guilt after using cannabis can also be confounded by the

illegality of the drug

• Assessement instruments used in general population surveys may not reach a part of illegal drug users. Even if this is less true for cannabis than for other illicit drugs, many users are in institutions or homeless.

• There is not a consensus on a precise definition of what cannabis related problems are.

Extract from the general public booklet of the 2005 cannabis campaign in France:

The Cannabis Abuse

Screening Test (CAST): Back from epidemiology to clinic…

Cannabis Abuse Screening Test (CAST)

• Have you ever smoked cannabis before midday? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

• Have you ever smoked cannabis when you were alone? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

• Have you ever had memory problems when you smoked cannabis? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

• Have friends or members of your family ever told you that you ought to reduce your cannabis use? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

• Have you ever tried to reduce or stop your cannabis use without succeeding? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

• Have you ever had problems because of your use of cannabis (argument, fight, accident, bad result at school, etc.) Precise : /_____________/? – never (0) – rarely (0) – from time to time (0) – fairly often (1) – very often (1)

Existing screening tests for problematic cannabis use

• NAME Number of items Authors

• CAGE-cannabis 4 Midanik et al, 1998• SDS (Severity of Dependence Scale) 5 Gossop et al, 1995• Ontario alcohol and other drug opinion survey 5 Ferris et al.., 1994• CAST (Cannabis abuse screening test) 6 Beck and Legleye, 2003• PUM (Problematic use of Marijuana) 8 Okulicz-Kozaryn, 2007• CUDIT (Cannabis Use Disorders Identification Test) 11 Adamson and Sellman,

2003• MINI-cannabis 11 Sheehan et al, 1997• ALAC (Alcohol Advisory Council of New Zealand)11 ALAC, 1996

• DSM-IV dependence adapted in – National Household Survey on Drug Abuse 15 Kandel et al, 1997

• Knowing cannabis test 16 Kerssemakers, 2000• CAPQ-SF (Cannabis-Associated Problem Quest.) 22 Lavender et al, 2008• MSI-X (Marijuana Screening Inventory) 39 Dale, 2003• CPQ (Cannabis Problem Questionnaire) 46 Copeland et al, 2005• MCQ (Marijuana Craving Questionnaire) 47 Heishman et al, 2001• MEEQ (Marijuana Effect Expectancy Quest.) 70 Schafer and Brown, 1991

Problematic cannabis use: general findings

• According to the litterature, about 0.5% to 3% of the whole population fulfill criteria for cannabis dependence or abuse in the last 12 months in Europe (Rehm et al., 2005) as well as in Australia or the United-States (Swift et al., 2001 ; SAMSHA, 2002).

• Figures are higher for men and for young adults• Early substance use is known to be associated with a

high risk of developing substance use disorders• ESPAD 2007 also provides a very relevant European

comparison on 17 countries, n~51,000 (Piontek et al., 2009)

Results from the CAST in the ESPAD study (Piontek et al., 2009)

Conclusions

• Measuring the proportion of problematic or dependent cannabis users is complex

• A great number of concepts and tools exist to monitor problematic cannabis use

• Implementing a common screening tool can deliver important information for prevention at the European level (ESPAD 2007)

• We still need to develop and validate screening tests which are more reliable in measuring adverse effects of cannabis use

Contact

INPES42, Bld de la Libération

93203 Saint-Denis Cedex

Tel : 01 49 33 22 22

www.inpes.fr

inpes@inpes.sante.fr