Supplementary Table S1. Specific scales for assessing cannabis use disorders Items Time- Aim n Sample Internal Test– Inter- Sensitivity/specificity (positive Correlations c predictive value/negative w o predictive value) compared it n with ‘gold standard’ (in h s bold) o i t s h t e e r n i c n y s ( tr C u r m o e n n b t a o c r h o ’ t s h α e ) r d a t a (i n b o l d ) ( κ , CPQ 12– 3 Screening

S-CAP 5987 ≥18 years who used 0.84 N/A N/A N/A Indices of (short cannabis at least c version). once per month a Lavender et n al . (2008) n a b i s u s e : 0 . 9 7 CPQ. 100 ≥18 years who used 0.55–78 0.98 0.74– DSM-IV: 0.84/0.84. Daily use: DSM-IV: C cannabis at least 0.55/0.83 0 o once in last 3 . p months 7 e 2 l ( a p n < d 0 e . t 0 a 1 l. ). ( D 2 a 0 il 0 y 5 u ) s e : 0 . 5 7 ( p < 0 . 0 1 ) CPQ-A 100 14–18 years who had used 0.72–0.88 0.91 N/A DSM-IV: 0.78/0.90. Frequency of DSM-IV ( cannabis in last use last 90 days: 0.52/0.90 0 s 90 days . h 8 o 0 rt ( v p e < r 0 si . o 0 n 1 ). ). M S a D rt S i : n 0 e . t 7 a 4 l. ( ( p 2 < 0 0 0 . 6 0 ) 1 ). F r e q u e n c y u s e l a s t 9 0 d a y s : 0 . 5 9 ( p < 0 . 0 1 ) CPQ-A-S 144 16–20 years who had used 0.70 N/A N/A DSM-IV: 0.83/0.78. Cut-off: 3 No data ( cannabis in last s month h o rt v e r si o n ). F e r n á n d e z - A rt a m e n d i e t a l. ( 2 0 1 2 a ) CPQ-A-S 225 14–18 years who had used 0.73 N/A N/A N/A Logistic ( cannabis in last r s 90 days e h g o r rt e v s e s r i si o o n n a ). n P a r l o y u s d i f s, o a o d t j e u t s a t l. e ( d 2 t 0 o 1 h 0 e ) a v y c a n n a b i s u s e : 0 . 3 8 4 ( p < 0 . 0 0 1 ) CPQ-A 144 16–20 years who had used 0.86 N/A N/A Abuse: 0.77/0.76. Cut-off: 4.5. Intensity ( cannabis in last Dependence: 0.80/0.87. u s month Cut-off: 5.5 s h e o l rt a v s e t r m si o o n n t ). h F : e 0 r . n 5 a 4 n 6 d ( e p z < - 0 A . rt 0 a 0 m 1 e ). n C d A i S ( T 2 : 0 0 1 . 2 5 b 8 ) 2 ( p < 0 . 0 0 1 ) CAST 6 Lifetime Screening

CAST. 144 16–20 years who had used 0.84 N/A N/A DSM-IV: 0.83/0.87. Cut-off: 5 N/A F cannabis in last e month r n á n d e z - A rt a m e n d i e t a l. ( 2 0 1 2 a ) CAST. 985 French Army N/A N/A N/A 70.8% of self-reported+ reported Urine M urine sample+. 2.6% of s a self-reported– reported a ri urine sample+ m m p o l u e t + o : u 1 e 6 t . a 9 l. % ( 2 ( 0 1 1 3 0 . ) 8 – 2 0 . 6 ). S e lf - r e p o r t r e g u l a r u s e : 8 . 2 %

( 6 . 4 – 1 0 . 6 ). C A S T p o s it i v e ( > 2 ) : 6 %

( 4 . 6 – 7 . 7 ) CAST. 241 18–25 years who are 0.72–0.75 0.82– N/A DSM-IV dependence: 0.89/0.49 (cut- C regular cannabis off: 4). 0.57/0.84 (cut-off: u users (use at 12) e least 12 times in n last 12 months) c a - R o y o e t a l. ( 2 0 1 2 ) DSM-IV abuse: 0.81/0.57 (cut-off: 4). 0.74/0.69 (cut-off: 9) CAST. 509 French Army referred to 0.87 N/A N/A 0.85/0.85 (no data about ‘gold N/A G treatment standard’). Cut-off: ≥3 h e o r g h i e v e t a l. ( 2 0 0 9 ) CUDIT. 8–10 6 Screening A ll st u d i e s i n c l u d e d CUDIT-R. 144 Participants taking part in a 0.91 0.87 N/A SCID: 0.91/0.90. Cut-off: ≥13 OTI Q- A clinic trial of Sc d CBT for or a depression and e m substance (re s misuse ce o nt n ca e nn t abi a s l. us ( e 2 fre 0 qu 1 en 0 cy ) ) 0.7 05 (p <0 .00 1). R C Q tot al (c urr ent m oti vat io n) 0.5 86 (p <0 .00 1) CUDIT. 593 Current cannabis users 0.72 N/A N/A Smoking at work/school: N/A A (once at least in 0.64/0.69. Smoking and n 6 months). driving: 0.58/0.59. n Adolescents and Depressive symptoms: a young adults 0.50/0.59. Smoking to h cope: 0.66/0.67. Self- e evaluation: 0.71/0.70. i Cut-off: 6–8 m

e t a l. ( 2 0 0 8 ) CUDIT. 1179 Adult cannabis users who 0.75 N/A N/A Drive after cannabis use past 12 N/A T reported past 3 months: 0.39–0.51/0.83– h months cannabis 0.89 (0.61–0.64/0.74– a use 0.77). Use of other illicit k drugs in past 12 e months: 0.44–0.53/0.76– & 0.84 (0.43–0.47/0.82– D 0.83). One harm from a use in past 12 months: v 0.48–0.63/0.83–0.89 is (0.37–0.42/0.91–0.93). ( Cut-off: 6–8 2 0 1 1 ) MPS. 19 Lifetime Screening 160 Marijuana users seeking N/A N/A N/A N/A Mean Jungerman treatment nu & m Laranjeira be (2008) r of joi nt s pe r da y (r =0 .16 3, p= 0.0 4). Pe rc en ta ge of da ys sm ok ed (r =0 .15 4, p= 0.0 53 )

RCQ-M. 11 12 Screening 175 Incarcerated adolescents 0.801– 0.504 N/A N/A Conduct Stein et al. 0 dis (2010). . or 8 de 2 r 5 sy m pt o m co un t (p re vi ou s 12 m on th s): 0.3 05 (p <0 .00 1). M ari ju an a de pe nd en ce sy m pt o m co un t (lif eti m e): 0.4 66 (p <0 .00 1). Da ys us ed m ari ju an a (p re vi ou s 3 m on th s): 0.6 23 (p <0 .00 1) MSI-X. 31 Lifetime Screening Adults referred to 0.89–0.90a No data No data 0.73–0.8/0.89–0.96a. Cut-off 6a DSM-IV: A treatment (107) 0.8 l 11 e (p x <0 a .00 n 1). d D e A r ST & - 20 L : e 0.5 u 31 n (p g <0 ( .00 2 1). 0 S 0 A 6 SS ) I-3 su bs cal esb 0.4 18 – 0.6 26 (p <0 .00 1). A SI (lif eti me ye ars ca nn abi s, ne ed for dr ug ab us e tre at me nt) b 0.2 78 – 0.3 76 (p <0 .00 1). M A ST 0.1 42 (p >0 .00 1)

CPQ, Cannabis Problems Questionnaire; S-CAP, Short-Cannabis Associated Problem Questionnaire; N/A, not available; Diagnostic and Statistical Manual of Mental Disorders; CPQ-A, Adolescent Cannabis Problems Questionnaire; CPQ-A-S; Adolescent Cannabis Problems Questionnaire, short form; CAST, Cannabis Abuse Screening Test; CUDIT, Cannabis Use Disorder Identification Test; CUDIT-R, Cannabis Use Disorder Identification Test – Revised; CBT, cognitive behavioral therapy; OTI, past month level of cannabis use from Q-Score of the Opiate Treatment Index; RCQ, Risk and Consequences Questionnaire; MPS, Marijuana Problem Scale; RCQ-M, Risk and Consequences Questionnaire-Marijuana; MSI-X, Marijuana Screening Inventory; DAST-20, Drug Abuse Screening Test (20 items); SASSI- 3, Substance Abuse Subtle Screening Inventory; ASI, Addiction Severity Index; MAST, Michigan Alcohol Screening Test. a From other study in community and clinical sample (cited in method of Alexander & Leung, 2006). b Only significant correlations are shown.