Cannabis-Related Treatment Demands in Belgium: A Socio-Demographic and Treatment Seeking Profile

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1 Arch Public Helth 2009, 67, Cnnbis-Relted Tretment Demnds in Belgium: A Socio-Demogrphic nd Tretment Seeking Profile by Colpert K 1, Vnderplsschen W 1, Vn Hl G 2, Schuyten G 3, Broekert E 1 Abstrct Aims Most people pper to stop using cnnbis when getting older, but certin subgroup becomes cnnbis dependent, hs problems in vrious life res nd needs tretment. Our im is to compre number of sociodemogrphic nd tretment seeking vribles between tretment seekers with primry cnnbis problems nd those with primry lcohol, opite, mphetmine or cocine problems. Understnding how primry cnnbis users seeking tretment differ from other tretment seekers my ssist clinicins in better tiloring tretment processes to clients needs. Methods For this purpose, intke informtion on 1,626 persons seeking tretment in one of 16 tretment gencies in the province of Antwerp (Belgium) ws registered vi n on-line web ppliction. Primry cnnbis users seeking tretment were compred with primry lcohol, opite, mphetmine nd cocine users by mens of bivrite nlyses (Chi-squre tests nd nlyses of vrince), followed by four logistic regression nlyses. Findings 14.5% of ll clients used cnnbis s their primry drug. Compred to primry lcohol, opite, mphetmine or cocine users seeking tretment, cnnbis users seeking tretment ppered to be more often mle, younger thn 30 yers old, Belgin nd student. They re often referred to tretment by police or justice nd 43.6% of them cn be considered singlesubstnce users. Multivrite nlyses showed tht besides ge nd sex, using no other substnces thn the primry drug nd being registered in outptient fcilities only were significnt determinnts for being primry cnnbis user seeking tretment. Conclusions Primry cnnbis users cn clerly be differentited from other drug users seeking tretment. Although cnnbis plys n importnt prt in polydrug use pttern, persons who hve cnnbis s their primry drug often use only this one substnce. Since they regulrly Ghent University, Deprtment of Orthopedgogics University of Antwerp, University Scientific Institute for Drug Problems Ghent University, Deprtment of Dt-nlysis kthy.colpert@ugent.be

2 180 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. hve brief contcts with tretment gencies, more reserch is needed to mesure the effect of this brief intervention. Keywords Cnnbis, Tretment Demnd, Substnce Abuse Tretment, Drug Use, Demogrphics Introduction In Europe s well s in the United Sttes, cnnbis is the most commonly used illegl substnce (1, 2). Bsed on the vilble figures, the Europen Monitoring Centre on Drugs nd Drug Addiction (1) concludes tht the use of cnnbis in the Europen Union is no longer rising nd tht there re signs of stbilistion (nd in some countries even decrese). Most people pper to stop using cnnbis when they get older nd their socil roles nd responsibilities chnge (3, 4, 5). Resons for doing so re chnges in living circumstnces, peer reltions or working conditions, but lso concerns bout helth in generl nd becoming cnnbis-dependent in prticulr (6). Although some my consider cnnbis soft drug with few consequences, regulr cnnbis use hs been linked to impirment in cognitive functions, helth (e.g. respirtory problems), employment nd psychologicl functioning (7). Regulr use nd especilly erly onset of cnnbis use mong dolescents is ssocited with higher levels of other risk behviours, fighting, bullying nd school, helth nd psychologicl problems (8). On the other hnd, lrge-scle studies hve demonstrted tht the probbility of developing cnnbis buse or dependence ppers to be rther low (5, 9, 10). The risk of developing mrijun dependence mong those who hve ever tried it, cn be situted round 8% to 10% (10, 11). It is importnt to note tht since illicit drug use ppers to be more trnsient in nture thn, for exmple, lcohol use, it is very unlikely tht people will become cnnbis-dependent fter the ge of 30 (10). Although the overll probbility is rther low, vrious studies crried out in the United Sttes demonstrte tht the pst-yer prevlence of mrijun use disorders hs slightly risen over the pst decde. When pst-yer mrijun users re considered, the pst-yer prevlence of DSM-IV disorders mrijun buse or dependence hs risen from 30.2% to 35.6% (12). Severl studies show tht minority of persons with dignosis of cnnbis buse or dependence seek tretment (13, 14). Furthermore, when they ctully do so, lrge gp ws demonstrted between the onset of the disorder nd the first drug tretment episode: 5.5 yers for cnnbis buse nd 3.1 yers for cnnbis dependence (14). Still, Europen tretment demnd dt tend to show significnt increse between 1999 nd 2004 regrding the proportion of tretment seekers who use cnnbis s their primry drug (1). The sme evolution cn be observed in the United Sttes on the bsis of the 2005 Tretment Episode Dt Set (TEDS) (15). Overll, in 15% to 16% of ll tretment requests, cnnbis ppered to be the primry drug. Obviously, it hs to be tken into ccount tht this increse

3 Chrcteristics of cnnbis users in tretment 181 is possibly due to decrese of the help-seeking behviour of users of other types of substnces. Reserch on the chrcteristics of cnnbis users seeking tretment is scrce nd focuses lmost entirely on the North Americn nd Cndin sitution (16, 17, 18, 19). Wht we cn lern from these studies is tht cnnbis users seeking tretment re more likely to be mle, single, under the ge of 20 nd in high school. Legl, school or fmily-bsed pressure to enter tretment re commonly present (19). Furthermore, they pper to hve problems in vrious life domins: helth (especilly respirtory problems), psychologicl sttus, memory, motivtion, socil interction, interest in ctivities, etc. (20). The mjority of published studies focusing on the chrcteristics of primry cnnbis users seeking tretment nd the outcomes of their tretment re bsed on experimentl mrijun-specific tretment progrmmes (16, 17). Becuse of the often stringent exclusion criteri tht were used to define the study smple, the findings of those studies regrding socio-demogrphic nd other chrcteristics my not be representtive for the cnnbis tretment-seeking popultion s whole. Objectives of the study As the number of cnnbis-relted tretment requests rises, it is importnt to gther bckground informtion on the socio-demogrphic, substnce-relted nd tretment seeking chrcteristics of this prticulr group of primry cnnbis users seeking tretment since differences between cnnbis nd other drug users my be of clinicl importnce in developing efficcious tretment interventions. A recent review (21) demonstrtes tht, t this point, no single psychotherpy hs clerly proven to be more effective thn nother for the tretment of cnnbis dependence, nd no phrmcologicl tretment yet exists. Despite the high prevlence of cnnbis use nd dependence, Nordstrom nd Levin (21) conclude tht the phenomenon remins rther understudied compred to other legl nd illegl substnces. In this study, tretment seekers with cnnbis s primry drug will be compred with tretment seekers who hve lcohol, opites, mphetmines or cocine s their primry drug in order to grsp the unique chrcteristics of primry cnnbis users seeking tretment. Understnding how tretment seekers with cnnbis s primry drug differ from those hving other substnces s primry drug my ssist clinicins in better tiloring tretment processes to clients needs. After ll, it is generlly cknowledged tht tretment which is dpted to clients needs nd chrcteristics (e.g. type of substnce buse) is more effective (22). Methods Smple This study ws set up s multi-centre, cross-sectionl study in inptient nd outptient substnce buse tretment gencies in the province of Antwerp (Belgium). During the sixmonth registrtion period (Mrch 1, August 31, 2004), 1,935 tretment requests were

4 182 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. registered, representing ll tretment requests of persons seeking tretment for problems relted to legl nd/or illicit substnces in one of the prticipting tretment gencies. In totl, six outptient nd ten inptient tretment gencies or units for substnce busers prticipted in the study, representing nerly ll centres in this province where people with lcohol or drug problems cn get help. We decided not to include the psychitric wrds in generl hospitls becuse people with vrious psychitric disorders (e.g. nxiety, mood- nd substnce-relted disorders) re dmitted to this type of tretment setting, nd no seprte tretment progrmme exists for people with substnce-relted disorders. Privte generl prctitioners, psychologists nd psychitrists were lso excluded from the study becuse substnce buse gencies or units were trgeted rther thn individul therpists. Almost two-thirds (63.0%) of ll intke interviews took plce in residentil fcilities, with the other 37.0% in outptient gencies. Procedure Informtion on the tretment seekers chrcteristics ws registered during the initil intke interview. An initil intke interview ws defined s the first fce-to-fce contct between person requesting tretment nd helth cre professionl (e.g. psychologist, socil worker, counsellor) in order to bilterlly exchnge informtion. After this initil intke interview, the clinicin decided together with the person whether tretment ws necessry; if so, tretment ws initited. Since informtion ws gthered nd registered by clinicins, this contributed to the collection of high-qulity dt by persons specilised in this field, who hve close contcts with clients (23). On the other hnd, registrtion by clinicins includes the risk of soclled registrtion ftigue, while stff turnover nd the involvement of vrious persons registering my hmper perfect stndrdistion of registrtion procedures (24). These issues were ddressed by limiting the registrtion to six-month period, orgnising severl trining sessions, giving finncil incentives, elborting n extended registrtion mnul, nd providing helpdesk where clinicins could get prompt nswers to their questions. Furthermore, fter finishing the reserch project, individul feedbck ws provided to ll prticipting tretment gencies regrding the number nd chrcteristics of their respective client popultions, which could serve future service plnning nd development (25). In order to explore the persons tretment seeking ptterns without violting their privcy, unique client identifier ws introduced for this study which permitted trcking of individuls cross tretment demnds nd gencies. This identifier, in combintion with other stble personl informtion (e.g. yer of birth nd sex), ws lso used for eliminting multiple counts when nlysing chrcteristics of unique tretment seekers. Although some double counts will not hve been recognised s such, bsolute perfection is neither possible nor required (26). After ll, the min purpose ws to reduce the probbility of the number of multiple counts to level tht is good estimtion of the true number of unique tretment seekers (23). Furthermore, this method is lso dvised by the EMCDDA in order to void distortion of reserch results.

5 Chrcteristics of cnnbis users in tretment 183 Instrument Due to the lck of common registrtion tool in Belgin substnce buse tretment (27), specific instrument ws developed. The vribles included were lrgely derived from questions or vribles in the Tretment Demnd Indictor protocol, common Europen stndrd mnul on tretment demnd registrtion developed by the Pompidou Group/Europen Monitoring Centre for Drugs nd Drug Addiction (EMCDDA) (23) nd from items in the Europen Addiction Severity Index (EuropASI), semi-structured interview tht offers the possibility for clinicins nd reserchers to mp the severity of functioning problems in vrious life res (28, 29). All tretment gencies were involved in the development nd elbortion of the instrument nd reserch design in order to enhnce prticiption. Since this ws n dditionl registrtion (besides the lredy existing vrious dministrtive registrtion procedures in ech gency), only limited number of vribles ws collected: socio-demogrphic dt (sex, ge, plce of residence, country of birth, employment nd living sitution); substnce-relted informtion (primry drug, regulr use of vrious types of substnces); injecting behviour (ever, during the lst 12 months); previous tretment episodes; nd type of tretment centre (inptient vs. outptient). The primry drug ws defined s the drug tht ccording to the clinicin cuses the person the most problems. This definition is in ccordnce with the guidelines in the EuropASI mnul (29). For dt collection purposes, secure online web ppliction ws developed with considerble dvntges compred to pper-bsed registrtion, e.g. improved dt qulity nd communiction between clinicins nd reserchers. A lrge mjority of tretment centres mde use of the ppliction. Only two tretment centres filled out registrtion sheets nd sent them in on monthly bsis to the reserchers due to the fct tht internet ccess ws not redily vilble. Dt nlysis All dt were converted to nd entered into SPSS, nd thorough dt qulity check ws performed. If necessry, uncler or contrdictory informtion ws pssed on to the person in the centre responsible for completion or correction of the registrtion. Sociodemogrphic nd tretment seeking differences between five groups (primry drug: lcohol, cnnbis, opite, mphetmine, cocine) were exmined. Other substnces (e.g. methdone, sedtives, xtc) were less often cited s primry drug nd were therefore not included in further nlyses. For 20 clients, the primry drug ws unknown. These dt were lso excluded from further nlyses. For ctegoricl vribles, chi-squre tests were used; for continuous vribles, nlysis of vrince (ANOVA) ws used. Only results yielding p- vlue < 0.05 were considered sttisticlly significnt. When the overll chi-squre or F- sttistic ws significnt, post-hoc tests were used to evlute the significnce of the differences between pirs of groups. For ctegoricl vribles, the test for pirwise comprison of column proportions ws used, djusting the p-vlues for multiple comprisons through the Bonferroni method. For continuous vribles, the Bonferroni post-hoc test ws used. After

6 184 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. these bivrite comprisons, selection of vribles ws entered in logistic regression model in order to determine which vribles were independently ssocited with being primry cnnbis user seeking tretment, s compred to four reference groups: primry lcohol, opite, mphetmine or cocine users seeking tretment. Four logistic regression nlyses were crried out in order to find the best fitting model tht describes the reltion between dependent binry vrible nd fixed set of independent vribles. The vribles tht were selected re: ge, sex (mle/femle), Belgium s country of birth (yes/no), living together with prtner nd/or children (yes/no), being currently employed (yes/no), hving legl problems (yes/no), regulrly using the primry drug only (yes/no), registered in outptient tretment centres only (yes/no), registered more thn once (yes/no) nd immedite strt of tretment fter intke interview (yes/no). Selection of vribles ws lrgely bsed on previous reserch findings. When compring groups of clients, incomplete registrtion forms were excluded from the nlysis. Unless mentioned otherwise, ll percentges should be red s vlid percentges. Results Smple description After creful nlysis of multiple counts on the bsis of the unique client identifier, it ws concluded tht the 1,935 registered tretment requests corresponded to 1,626 unique persons. The mjority ws registered only once (86.6%), while 9.6% ws registered twice, nd 3.8% three or more times. The smple consisted of 26.4% women nd 73.4% men. The men ge ws 36.7 yers (SD=12.9). Overll, lcohol ws most commonly cited s the primry drug (n=758; 46.6%), followed by cnnbis (n=236; 14.5%), opites (n=130; 8.0%), mphetmines (n=123; 7.6%), nd cocine (n=100; 6.1%). Methdone, sedtives, xtc, multiple substnces or other substnces were less often cited s primry drug (n=259). Sociodemogrphics of tretment seeking primry cnnbis users The lrge mjority of primry cnnbis users ppers to be mle, with only 13.1% femle (Tble 1). Compred to the primry lcohol nd mphetmine users, this proportion of women is significntly lower (29.3% nd 34.1% respectively). Primry cnnbis users re lso younger thn ll other tretment seekers. They hve men ge of 23.6 yers nd 81.3% is younger thn 30 yers old. Only the primry mphetmine users re lso generlly under the ge of 30. All other groups hve men ge of 30 yers or older. Further, only 8.6% of the primry cnnbis users were not born in Belgium. This is considerbly lower thn the cocine (18.6%) nd opite (35.9%) subgroups. When the clients living, working nd judicil conditions re considered, we observe tht primry cnnbis users re more often still students (in 41.2% of the cses) compred with ll other groups, even the mphetmine users (18.8%) who hve similr men ge s the cnnbis users. The sme conclusion cn be drwn regrding their living conditions: primry cnnbis users more often live with their prents (52.4%) compred to other tretment seekers. The results lso show

7 Chrcteristics of cnnbis users in tretment 185 tht both primry cnnbis nd mphetmine users hve in lmost hlf of the cses current problems with police or justice. However, different types of legl problems cn be observed: lmost hlf of the cnnbis users hving legl problems re involved in the therpeutic dvice procedure, while more thn third of the mphetmine users re on probtion fter detention. Therpeutic dvice is mesure through which youngsters who come into contct with the lw becuse of drug-relted offences (possession or use of illicit drugs, predominntly cnnbis) re referred to substnce buse tretment gencies in order to ssess whether their use is problemtic nd whether tretment is indicted. This mesure lso hs the objective for youngsters to become fmilir with the tretment system. Substnce use ptterns of tretment seeking primry cnnbis users Primry cnnbis users in comprison with primry lcohol users hve higher prevlence figures regrding the regulr use of mphetmines, hllucinogens, cocine nd ecstsy, but lower prevlence figures on the regulr use of sedtives. Compred with the other illicit drug users, we cn observe tht they re less likely to regulrly use cocine, opites nd sedtives. For the other substnces, more differentited picture needs to be drwn: regulr mphetmine use is lower in primry cnnbis users thn in primry cocine users, but not different from primry opite users; regulr ecstsy use is lower in primry cnnbis users thn in primry mphetmine users but not significntly different from primry cocine nd opite users. Overll, 43.6% of primry cnnbis users only uses cnnbis regulrly nd cn be considered single-substnce users, while in nerly ll other groups except for primry lcohol users (68.1%) this figure is remrkbly lower: between 17.7% (opites) nd 22.0% (cocine). Also, the group of primry cnnbis users hs injected significntly less often in the pst yer compred with primry mphetmine, cocine nd opite users. A tretment seeking profile of primry cnnbis users In only hlf of the cses primry cnnbis users hd tretment history. This ws significntly lower thn in ll other groups, since between 72.7% nd 81.6% of the other tretment seekers were lredy tretment-experienced. Of ll tretment seekers, primry cnnbis users hd sought tretment most often in outptient tretment gencies (in 70.3% of the cses). This figure ws significntly higher thn for lcohol nd cocine users; for mphetmine nd opite users the differences were not significnt. In 43.6% of the cses, primry cnnbis users were referred to tretment by police or justice officils. This is considerbly higher thn mong other groups, except for mphetmine users (34.1%). Finlly, we lso looked t the outcome of the intke interview: in qurter of the cses, primry cnnbis users did not strt tretment or were not referred to nother tretment centre. The intke interview remined without immedite consequence. For ll other groups this figure vried between 7.7% nd 11.4%. Tble 1: Comprison of primry cnnbis users with primry lcohol, opite, mphetmine or cocine users (n=1347)

8 186 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. Cnnbis (n=236) Vlid % Alcohol (n=758) Vlid % Opite (n=130) Vlid % Amphetmine (n=123) Vlid % Cocine (n=100) Vlid % Chi² (df=4) or t-vlue (df=4) p-vlue Group differences Sex Mle Femle Age < > , c, b, d, b, d, b Men ge (SD) 23.6 (7.83) 44.7 (10.81) 32.5 (7.89) 26.1 (8.43) 30.1 (7.17) , b, d Country of birth Belgium Living sitution Alone With prtner nd/or children With prents Homeless Employment sitution Employed Student Unemployed Invlidity Legl problems None Relese on bil or other conditions witing tril/sentencing Probtion fter detention Compulsory dmission NS Juvenile court Therpeutic dvice Regulr use substnces Alcohol (>= 5 glsses dy) Amphetmines Cnnbis Cocine Ecstsy Hllucinogens Opites Sedtives b, d, b, b, c, d b, d, d, b, c, d d, b, d,c, c, b, c, d, b, c, c b, c, d, b, c, d Only regulr use of primry drug , b, c, d

9 Chrcteristics of cnnbis users in tretment 187 Injected during lst yer b, c, d Tretment history , b, c, d Number of registrtions > , c, d Types of tretment centres Inptient Outptient Both NS Source of referrl No source of referrl Immedite surroundings NS Police or justice Specilised substnce buse tretment Generl hospitl Generl prctitioner Psychitric hospitl Outcome of intke interview Strt of tretment Immedite referrl to other centre Without consequences , d, d, b, d, b, d b, d, b, c, d, b, c, d : Significnt difference between primry cnnbis nd primry lcohol users b : Significnt difference between primry cnnbis nd primry opite users c : Significnt difference between primry cnnbis nd primry mphetmine users d : Significnt difference between primry cnnbis nd primry cocine users Independent determinnts of being primry cnnbis user Logistic regression nlyses (Tble 2) were performed in order to identify independent determinnts of being primry cnnbis user seeking tretment, while controlling for potentil effects of other relevnt vribles. Age ws significntly ssocited with being primry cnnbis user compred with three out of four reference groups (primry lcohol, opite or cocine users seeking tretment): being older decresed the odds of being primry cnnbis user. In comprison with primry mphetmine users, ge ws not significnt determinnt but sex ws ll the more: being mle incresed the odds of being primry cnnbis user by bout four times. Using no other substnces thn the primry drug ws significnt determinnt in ll four nlyses: it significntly incresed the odds of being primry cnnbis user s compred with tretment seekers with other illegl substnces s primry drug (opites, mphetmines or cocine) but decresed the odds of being primry cnnbis user s compred to primry lcohol users. Overll, living, working nd judicil sitution were less importnt determinnts, except in the nlysis with primry cocine users s reference group: being employed significntly decresed the odds wheres hving legl problems incresed the odds of being primry cnnbis user. Finlly, when tretment seeking vribles re concerned, being registered only in outptient fcilities incresed the

10 188 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. odds of being primry cnnbis user s opposed to being primry lcohol or cocine user wheres being registered more thn once during the registrtion period decresed the odds s compred to being primry mphetmine user. Tble 2: Binry logistic regression nlyses presenting Odds Rtios for being primry cnnbis user seeking tretment with primry lcohol, opite, mphetmine nd cocine users seeking tretment s reference groups Alcohol Opite Amphetmine Cocine Exp(β) 95% CI Exp(β) 95% CI Exp(β) 95% CI Exp(β) 95% CI Sex: mle ** Age.838** ** ** Country of birth: Belgium ** Living sitution: with prtner nd/or children Working sitution: employed ** ** Legl problems * Use of primry drug only.369** ** ** * Registered in n outptient setting only 4.748** ** Registered more thn once * Immedite strt of tretment fter intke Totl number of tretment seekers included in the nlysis Ngelkerke R² * Significnt t the.05 level ** Significnt t the.01 level Discussion Prevlence of cnnbis s primry drug within tretment settings During the six-month registrtion period 1,626 unique clients were registered. Alcohol ws the most commonly cited primry drug (46.6%) followed by cnnbis (14.5%), opites (8.0%), mphetmines (7.6%) nd cocine (6.1%). It is striking to observe tht when we look t the illegl drugs, cnnbis is first in line; lmost twice s mny tretment seekers climed cnnbis s their primry drug (14.5%) compred with ny of the other illegl drugs. In Europen tretment demnd figures, on the other hnd, opites re still first in line, but the number of primry cnnbis users is stedily rising (1). Of course, we hve to tke into ccount one of the min limittions of registrtion reserch: results re determined to lrge

11 Chrcteristics of cnnbis users in tretment 189 extent by the number nd types of tretment centres tht hve prticipted in the study, e.g. the proportion of inptient versus outptient centres (30). Still, with this study we covered very wide rnge of services, s result of which our figures cn be considered representtive for the client popultion in this prticulr tretment system. Severl hypotheses cn be formulted regrding the rise of primry cnnbis users seeking tretment, but thus fr no study hs been ble to indicte which hypothesis is correct (1). According to our opinion, severl evolutions re intercting with ech other. First, more people hve strted (regulrly) using cnnbis in the pst yers, resulting in more people in bsolute numbers who experience difficulties or problems relted to its use nd eventully seek tretment. This tendency of incresed use mong the generl popultion is not seen for other substnces for the moment. Second, severl studies hve exmined the potency of cnnbis nd relted chnges over the yers (30, 31, 32) nd found tht the potency of cnnbis hs systemticlly incresed, lso in the Netherlnds, one of Belgium s neighbouring countries. They suggested tht this could hve n effect on cnnbis-relted problems nd tretment demnd. Chrcteristics of primry cnnbis users seeking tretment The objective of this rticle ws to compre tretment seekers with cnnbis s primry drug with those with lcohol, opites, mphetmines or cocine s primry drug on number of sociodemogrphic nd tretment seeking vribles. The sociodemogrphic profile of the former emerged s mle, younger thn 30 yers old, Belgin nd student. This profile is lrgely consistent with previous reserch, lthough the sex differences re more pronounced in our study (19). We prticulrly wnt to focus ttention on cnnbis use mong students in tertiry eduction. Severl Americn studies hve estimted lst-yer prevlence figures to be situted round 30% (34, 35). A recent study in Antwerp (Belgium) mong university nd college students, bsed on 5,530 questionnires, demonstrted tht 22% of the university students hd used cnnbis in the lst yer. The uthors concluded tht students re more t risk of using cnnbis thn their non-college-ttending peers since the lst-yer prevlence is considerbly higher thn the lst-yer prevlence of cnnbis use in the generl Belgin popultion (ge 18-25): 22% versus 12.2% (36). When these figures re linked to our results, it becomes cler tht cnnbis use mong students cn result in number of cnnbis-relted problems nd in some cses need for tretment. Therefore, it would be useful to implement prevention cmpigns trgeted t university nd college students nd to engge in thorough screening nd erly interventions (37). Overll, polydrug use hs become the rule rther thn the exception. In society where diversity of psychoctive substnces is vilble, it is esier for users to strt using other substnces tht replce or complement their primry drug or to experiment with vrious combintions (38). Our study confirms this finding, except for tretment seekers with lcohol or cnnbis s primry drug. While bout 80% of ll tretment seekers with mphetmine, cocine or opites s primry drug re polydrug users, the percentges mong tretment seekers with lcohol (31.9%) or cnnbis (56.4%) s primry drug re much lower. Further-

12 190 Colpert K, Vnderplsschen W, Vn Hl G, Schuyten G, Broekert E. more, multivrite nlyses showed tht using no other substnces thn the primry drug ws significnt determinnt for being primry cnnbis user seeking tretment compred to the four reference groups (primry lcohol, opite, mphetmine nd cocine users seeking tretment). On the other hnd, cnnbis is the substnce tht is most often used in ddition to clients primry substnce, even to higher degree thn lcohol. Further, when other chrcteristics of tretment seekers with cnnbis s primry drug re concerned, the high number of persons with legl problems (47.2%) nd correspondingly high number of referrls by police or justice (43.6%) lso ctches the eye. Other Belgin reserch hs demonstrted tht overll most registered drug-relted offences were relted to cnnbis (39). Since cnnbis is the most widely used illicit substnce (2, 40), it is not surprising tht the lrgest shre of people who re cught by the police for substnce-relted offences nd potentilly referred to tretment hve cnnbis s their problem drug. Furthermore, this high number of referrls by police or justice cn prtly be explined by the high number of young people in the group of tretment seekers with cnnbis s primry drug: lthough the possession of smll mounts of cnnbis is less often prosecuted when there re no ggrvting circumstnces, the possession of cnnbis by minors remins priority of police nd justice in Belgium. Finlly, our study lso demonstrtes tht in 25.8% of the cses, the intke interview of tretment seekers with cnnbis s primry drug does not result in the strt of tretment episode or in the referrl to nother centre. It would be useful to crry out study on how these persons experienced this brief contct with tretment gency. Second, in the frmework of moving towrds more evidence-bsed prevention, it would be useful to know if this prticulr intervention ctully hs n effect on youngsters cnnbis using behviour, since time nd resources in tretment services re limited nd witing lists re relity. In other studies, brief tretment interventions hve certinly proven to be effective in vrious situtions nd for vrious trget groups, e.g. substnce-busing dolescents nd primry cre popultions (41, 42). Consequently, this my lso be n effective intervention for (young) cnnbis users. Limittions of the study Although this study hs severl strengths, including the lrge coverge of prticipting tretment centres nd the conscientious orgnistion of dt collection (e.g. vi online web ppliction), some limittions need to be mentioned. As reported in the methodology section of this pper, we chose to keep the number of vribles s limited s possible to ensure mximum prticiption of the tretment centres. As result, we lck detiled informtion in certin res, e.g. on substnce use ptterns (such s sequentility or simultneity of polydrug use, DSM-IV buse or dependence dignoses), tretment history nd psychitric problems. Second, working with tretment demnd dt mens tht the generlisbility to other smples is not self-evident. Ech tretment system hs its own chrcteristics (e.g. dmission nd referrl policies or connections with the criminl justice system) tht influence the results. Nevertheless, it is generlly cknowledged tht tretment smple studies cn result

13 Chrcteristics of cnnbis users in tretment 191 in vluble informtion for further tretment plnning nd orgnistion (43). Another limittion could be tht we relied on self-reported dt; biologicl testing ws not used by the registering tretment centres. However, numerous studies hve confirmed the vlidity nd relibility of self-reported dt regrding the use of licit nd illicit substnces (44, 45, 46). A finl limittion is tht in wy we hve reduced nd hve not sufficiently cknowledged relity by creting subgroups vi the vrible primry drug since the lrge mjority of clients re polydrug users (47). However, numerous studies hve relied on this prticulr vrible to compre (sub)groups of drug users nd hve found conclusive evidence to support this grouping strtegy (48, 49, 50). The definition (29) implies tht the primry drug is the drug tht ccording to the clinicin cuses the person the most problems, compred to other substnces tht person possibly (mis)uses. These problems cn be situted in vrious life res (employment, socil reltions, psychologicl helth, physicl helth), but no hierrchy is provided in the EuropASI mnul. As result, it is theoreticlly possible tht when person regulrly nd excessively uses lcohol nd occsionlly intrvenously uses mphetmines the clinicin hs selected lcohol s primry drug s the intke interview hs shown e.g. tht the person s lcohol use leds to serious problems with his or her fmily nd employer, is closely linked to depressive episodes nd driving under the influence of lcohol. Of course, the tretment pln will lso hve to del with the mphetmine use since IV use hs severe consequences for person s physicl helth. In cse severl substnces re eqully cusing the person problems, the clinicin lso hs the possibility to indicte multiple drugs s primry drug. References 1. Europen Monitoring Centre on Drugs nd Drug Addiction (EMCDDA). Annul report 2007: the stte of the drugs problem in Europe. EMCDDA: Lisbo, Substnce Abuse nd Mentl Helth Administrtion (SAMHSA) Ntionl Survey on Drug Use nd Helth. SAMHSA: Rockville MD, Agosti V, Levin FR. Predictors of Cnnbis Dependence Recovery Among Epidemiologicl Survey Respondents in the United Sttes. Am J Drug Alcohol Abuse 2007; 33: Chen K, Kndel DB. Predictors of cesstion of mrijun use: An event history nlysis. Drug Alcohol Depend 1998; 50: von Sydow K, Lieb R, Pfister H, Hofler M, Sonntg H, Wittchen HU. The nturl course of cnnbis use, buse nd dependence over four yers: longitudinl community study of dolescents nd young dults. Drug Alcohol Depend 2001; 64: Terry P, Wright KA, Cochrne R. Fctors contributing to chnges in frequency of cnnbis consumption by cnnbis users in Englnd: A structured interview study. Addict Res Theory 2007; 15: Klnt H. Adverse effects of cnnbis on helth: n updte of the literture since Prog Neuropsychophrmcol 2004; 28: Kokkevi A, Gbhinn S, Spyropoulo M. Erly Initition of Cnnbis Use: A Cross-ntionl Europen Perspective. J Adolesc Helth 2006; 39: Chen CY, O Brien MS, Anthony JC. Who becomes cnnbis dependent soon fter onset of use? Epidemiologicl evidence from the United Sttes: Drug Alcohol Depend 2005; 79: Wgner FA, Anthony JC. Into the world of illegl drug use: Exposure opportunity nd other mechnisms linking the use of lcohol, tobcco, mrijun, nd cocine. Am J Epidemiol 2002; 155:

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