Table 2. Summary of Clinical Trials of Psychotherapy Treatment for Cannabis Use Disorder.

Study	No. of Participants	Inclusion Criteria	Treatment Conditions	Primary Outcomes	Follow-Up	Monitoring of Cannabis Use	Results
CBT trials
Stephens et al., (1994)16	212	Used cannabis at least 50 of past 90 days, treatment-seeking cannabis users	Relapse prevention or social support group	Cannabis use, cannabis-related problems	1, 3, 6, 9, and 12 months after treatment	Self-report; collateral report; UDS at 3 and 6 months	No significant between-group differences were noted; overall, reductions were observed in cannabis use and associated problems; nearly two thirds achieved abstinence at the end of treatment, but only 14% sustained abstinence at 12-month follow-up.
Stephens et al., (2000)18	291	Used cannabis at least 50 of past 90 days, treatment-seeking cannabis users	14-session RPSG, 2-session IAI, or DTC	Cannabis use, dependence symptoms, cannabis-related problems	4, 7, 13, and 16 months from baseline	Self-report; collateral report	RPSG and IAI showed greater reductions in days used/month, times used/day, depression, and cannabis-related problems compared to DTC at 4-month follow-up; through 16 months, RPSG and IAI both maintained reductions in use, dependence symptoms, and cannabis-related problems. No significant differences were noted between RPSG and IAI
Copeland et al., (2001)19	229	Treatment-seeking cannabis users	6-session CBT (6CBT), 1-session CBT (1CBT), or DTC	Cannabis use	24 weeks from baseline	Self-report; UDS at follow-up	1CBT and 6CBT evidenced higher abstinence rates at follow-up (17.2% and 20.8%, respectively) compared to DTC (3.6%); 6CBT reported significantly reduced cannabis consumption compared to DTC
MET trials
Stephens et al., (2007)21	188	Expressed ambivalence about quitting cannabis, used at least 15 of last 30 days	Personalized feedback, MMF, or delayed feedback control	Cannabis use, dependence severity	7 weeks, 6 months, and 12 months	Self-report; UDS at all assessment visits	Personalized feedback participants reported fewer days of use/week (4.7), sessions/day of use (1.6), and dependence symptoms (2.4) than both MMF (5.4, 1.9, and 2.9, respectively) and delayed feedback control (5.7, 2.2, and 2.8, respectively); compared to MMF, personalized feedback participants maintained significantly fewer days of use at 12 months
Martin & Copeland (2008)26	40	Non–treatment-seeking adolescents, used at least once in past month	ACCU or DTC	Cannabis use, dependence severity	3 months after treatment	Self-report; UDS at baseline	Compared to DTC, ACCU participants reported fewer days of use (effect size = 0.71), dependence symptoms (effect size = 70), and quantity used/week (effect size = 0.22) at 3-month follow-up
de Gee et al., (2014)27	119	Non–treatment-seeking adolescents, at least weekly cannabis use	Weed Check (Dutch ACCU) or informational session	Cannabis use, dependence symptoms	3-months after treatment	Self-report	No main effects of treatment on cannabis use or other outcomes were noted; no between-group differences were noted; heavier use at baseline associated with better response to MET
McCambridge et al., (2008)28	326	Adolescents, at least weekly cannabis	Single-session MI or drug information and advice giving	Cannabis use, dependence severity, cannabis-related problems	3-months and 6-months after treatment	Self-report plus bogus saliva sample to encourage reliable reporting	Overall, reductions in use, dependence severity, and related problems were noted through 6 months; no significant between-group differences were noted at any point; low MI fidelity and practitioner effects limited findings
Stein et al., (2011)33	332	Non–treatment-seeking cannabis users, cannabis use at least 3 times in last 3 months	2-session MI intervention or assessment only	Cannabis use, problem severity	1, 3, and 6-months from baseline	Self-report	MI participants were less likely to use cannabis at 3-month follow-up (OR 0.53, 95% CI 0.33-0.86) but not at 1 month (OR 0.77, 95% CI 0.53-1.12) or 6 months (OR 0.74, 95% CI 0.47-1.17); expressed desire to quit at baseline was associated with decreased likelihood of use at 1 month (OR 0.42, 95% CI 0.20-0.90), 3 months (OR 0.31, 95% CI 0.12-0.83), and 6 months (OR 0.35, 95% CI 0.13-0.91), suggesting durability of MI effects among those expressing any desire to quit at baseline
MET/CBT trials
Marijuana Treatment Project Research Group (2004)12	450	Marijuana dependent, used at least 40 of past 90 days	2-session MET, 9-session multicomponent (MET/CBT/case management), or DTC	Cannabis use	4, 9, and 15 months after randomization	Self-report; UDS at baseline, 4 months, and 9 months	9-session group had significantly higher abstinence rates at 4 months (23%) than 2-session group (8.6%) and DTC group (3.6%); at 9 months, abstinence rates between 2-session and 9-session intervention did not differ significantly (9.5% vs. 15.6%). Also at 9 months, the 9-session intervention was better than the 2-session intervention on days of use, dependence symptoms, and abuse symptoms; difference in reduction of days used was maintained at 15 months; provided evidence that longer, more intensive treatment may result in better outcomes
Dennis et al., (2004)34	600	Age 12-18 years, self-report 1 or more DSM-IV criteria for abuse or dependence, used cannabis at least once in past 90 days	Trial 1: 5-session MET/CBT (MET/CBT5), 12-session MET/CBT (MET/CBT12), or family support network Trial 2: MET/CBT5, adolescent community reinforcement approach, or MDFT	Cannabis use, cost-effectiveness of intervention	3, 6, 9, and 12-months after intake	Self-report	No significant differences were noted among groups in days used or percent of participants in recovery; all groups showed improvements, with average days abstinent increasing from 52 to 65 days/quarter and percentage of participants in recovery increasing from 3% to 24%; changes were evident at 3 months and were stable for remainder of study; MET/CBT5 and adolescent community reinforcement approach were the most cost-effective
Walker et al., (2015)35	74	Cannabis dependent, used at least 50 of last 90 days	MET/CBT with maintenance check-up (MCU) or no check-up (NCU)	Cannabis use, re-engagement in therapy	3 and 9 months	Self-report; UDS at each time point	The MCU group had higher abstinence rates than the NCU group immediately after treatment (36% vs. 13%) and at 9-month follow-up (26% vs. 7%); these differences occurred prior to the maintenance check-ups, however, suggesting that the differences in rates were not due to check-ups; MCU participants did not attend more additional sessions
MET/CBT/CM trials
Budney et al., (2000)13	60	Treatment-seeking cannabis users, cannabis dependent, used in past 30 days	4-session motivational enhancement therapy (M), 14-session M + behavioral coping skills (MBT), or 14-session MBT + abstinence-based vouchers (MBTV)	Cannabis use	None	Self-report; twice-weekly UDS	MBTV averaged longer periods of continuous abstinence during treatment (4.8 weeks) than MBT (2.3 weeks) and M (1.6 weeks), as well as greater abstinence rates at end of treatment (MBTV 35%, MBT 10%, and M 5%). MBT and M did not significantly differ on outcomes
Budney et al., (2006)10	90	Treatment-seeking cannabis users, cannabis dependent	CBT only (CBT), abstinence-based voucher only (V), or CBT + voucher (CBT-V)	Cannabis use	3, 6, 9, and 12 months after treatment	Self-report; twice-weekly UDS	Through 1 year of follow-up, CBT-V maintained higher abstinence rates compared to CBT (38% vs. 20%); during treatment, V participants had longer period of continuous abstinence than CBT participants (6.9 vs. 3.5 weeks), whereas there was no significant difference between V and CBT-V participants; findings suggest that vouchers alone predict abstinence during treatment and that CBT provides durability of this effect over time
Carroll et al., (2006)36	136	Compelled by criminal justice system, cannabis dependent	MET/CBT, drug counseling, MET/CBT + CM, or drug counseling + CM	Cannabis use	6 months	Self-report; weekly UDS and at follow-up	Main effect of CM on continuous abstinence (d = 0.45) and total number negative drug screens (d = 0.29); MET/CBT/CM had the most consecutive negative screens during treatment; MET/CBT group continued to show reduction in use at 6 months compared to other groups
Kadden et al., (2007)11	240	Treatment-seeking cannabis users, cannabis dependent	MET/CBT, CM, MET/CBT/CM, or case management	Cannabis use	Every 3 months, up to 1 year	Self-report; UDS at each study visit	Frequency and quantity of use decreased across all groups; CM had higher proportion of days abstinent than case management at end of treatment (F (1,214) = 4.13, p <0.05); over follow-up period, MET/CBT/CM showed highest proportion of days abstinent; main effect of CM on period of continuous abstinence (t (215) = 2.00, p < 0.05); CM appeared to increase abstinence during treatment, whereas MET/CBT enhanced this effect over time
Carroll et al., (2012)14	127	Treatment-seeking cannabis users, cannabis dependent, involved in criminal justice system	CM abstinence (CMabs), CMabs + CBT (CMabs + CBT), CBT alone (CBT), or CBT + CM for adherence (CBT + CMadher)	Cannabis use	3, 6, 9, and 12 months after treatment	Self-report; weekly UDS and at each follow-up visit	CMadher did not improve CBT outcomes, and CBT worsened CMabs outcomes (CMabs had lower percentage of positive drug screens [57%] than CMabs + CBT [75%]); CMabs alone also showed most consecutive negative drug screens during treatment (3.3); CBT may not enhance CMabs, and CMadher may not enhance CBT
Litt et al., (2013)15	215	Cannabis dependent, treatment-seeking cannabis users	MET + CBT + CM for homework, MET + CBT + CM for abstinence, or case management	Cannabis use	5, 8, 11, and 14 months after treatment	Self-report; weekly UDS and at each follow-up visit	No main effect of treatment on cannabis outcomes; identified 4 response trajectories: treatment nonresponders (43%), late responders (25%), early relapsers (12%), and long-term abstainers (19%); long-term abstainers were more likely to be treated in MET/CBT/CM abstinence intervention, and continuous abstinence during treatment and increased self-efficacy predicted membership in all 3 “response” groups
Alternate approaches
Liddle et al., (2008)37	224	Adolescents meeting DSM-IV criteria for any substance use disorder	Individual CBT (CBT) or MDFT	Substance use problem severity; cannabis, alcohol, and other drug use	6 and 12 months after treatment	Self-report	Both treatments resulted in reductions in cannabis consumption but not in frequency of use; MDFT participants showed greater reductions in substance-related problem severity through 12 months, suggesting greater durability than CBT
Hendriks et al., (2011)38	109	Adolescents meeting DSM-IV criteria for cannabis use disorder	MDFT or CBT	Cannabis use	3, 6, 9, and 12 months after baseline	Self-report; UDS at 12 months	MDFT not superior to CBT for any cannabis use outcomes; both groups show reductions in frequency and quantity of use over 12-month study period; among high-severity users, MDFT participants evidenced greater reductions in days used than CBT participants
de Dios et al. (2012)39	34	Female; desire to quit or reduce use; used at least 3 times in past month; reported use as a way to relax, relieve anxiety, or calm down	2-session MI + mindfulness meditation (MI-MM) or assessment only	Cannabis use	1, 2, and 3 months after treatment	Self-report	MI-MM had fewer days of use at all follow-up points (6.1 fewer days at 1 month, 7.8 fewer at 2 months, and 6.8 fewer at 3 months); no significant between-group differences were noted in abstinence rates; largest overall abstinence rate of 15.4% between 1-2 months of follow-up; MI-MM participants were half as likely to use cannabis on days they meditated than on days they did not (OR 0.51, 95% CI 0.22–0.86)
Technologically based interventions
Kay-Lambkin et al., (2009)80	97	Comorbid depression and alcohol or cannabis misuse	10-session therapist-delivered MI/CBT (T), 10-session computer-based MI/CBT (C), or 1-session brief intervention (BI)	Cannabis use, “Improved” at 12 months (50% reduction in use, or <17 on BDI-II)	3, 6, and 12 months	Self-report	C and T groups showed greater reductions in days of use through 12 months compared to BI (C: from 11.9 to 3.3 days; T: from 15.0 to 5.7 days; BI: from 9.2 to 8.6 days); C intervention had greatest improvement (79% improved), followed by T (68%) and BI (44%).
Kay-Lambkin et al., (2011)81	274	Comorbid depression and alcohol or cannabis misuse	9-session therapist-delivered MI/CBT, 9-session clinician-assisted computer-based MI/CBT, or 9-session person-centered therapy	Changes in depression, alcohol use, and cannabis use from baseline to 3 months	3 months	Self-report	No significant differences in cannabis use were noted among groups
Budney et al. (2011)78	38	Treatment-seeking cannabis users, cannabis abuse or dependence, used at least 50 of past 90 days	Therapist-delivered MET/CBT + CM or computer-delivered MET/CBT + CM	Longest duration of continuous abstinence during treatment	None	Self-report; weekly UDS	No significant between-group differences were noted on cannabis use outcomes; suggests that computer-delivered MET/CBT + CM may be as effective as identical therapist-delivered treatment
Tossman et al., (2011)83	1292	Cannabis users seeking online treatment	50-day online counseling program (“Quit the Shit” [QTS]) or waitlist control	Cannabis use	3 months after randomization	Self-report	Compared to waitlist control, QTS had greater reductions in days of use and quantity of use (effect sizes = 0.98 and 0.75, respectively; per-protocol analysis); however, only 206 participants completed the follow-up (84% attrition rate); intent-to-treat analysis results were less powerful (although significant) with effect sizes of d = 0.20 for frequency of use and d = 0.11 for quantity of use
Rooke et al., (2013)82	225	Expressed desire to stop or cut down, used at least once in past month	6-week, 6-module “Reduce Your Use” intervention or 6-week, 6-module online educational information (control group)	Cannabis use	3 months after treatment	Self-report	At 6 weeks, “Reduce Your Use” reported fewer days of use (12.9 vs 14.9 days) and lower quantity used in past month (39.8 vs. 46.1 standard cannabis units) than in control group; difference in days of use was maintained at 3-month follow-up
Budney et al., (2015)79	77	Treatment-seeking cannabis users, diagnosed with cannabis use disorder, used at least 50 of past 90 days	2-session MET (BRIEF), 9-session MET/CBT (THERAPIST), or 9-session MET/CBT (COMPUTER)	Cannabis use	3 and 9 months after treatment	Self-report; twice-weekly UDS and at each follow-up visit	End of treatment abstinence rates did not significantly differ between THERAPIST (45%) and COMPUTER (47%); both were significantly greater than BRIEF (12.5%). At 3 months, COMPUTER had higher abstinence rates than BRIEF and statistically similar rates compared to THERAPIST; no significant differences in abstinence rates among groups were noted at 9 months; COMPUTER and THERAPIST had longer period of continuous abstinence than BRIEF (effect sizes 0.71 and 0.55, respectively), but no significant difference was noted between COMPUTER and THERAPIST; cost analysis revealed significantly greater cost per participant for THERAPIST ($427) compared to COMPUTER ($251) and BRIEF ($171)

CBT = cognitive-behavioral therapy; UDS = urine drug screen; RPSG = relapse prevention support group; IAI = individual assessment and intervention; DTC = delayed treatment control; MET = motivational enhancement therapy; MMF = multimedia feedback; ACCU = adolescent cannabis check-up; MCU = maintenance check-up; NCU = no check-up; OR = odds ratio, CI = confidence interval; MI = motivational interviewing; DSM-IV = Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; MDFT = or multidimensional family therapy; CM = contingency management; BDI-II = Beck Depression Inventory II;