Systematic research on psychosocial treatments for marijuana abuse or dependence began approximately 20 years ago, yet the number of controlled studies remains small. Behavioral treatments, such as motivational enhancement therapy (MET), cognitive-behavioral therapy (CBT), and contingency management (CM), as well as family-based treatments have been carefully evaluated and have shown promise. Outpatient treatments for marijuana abuse among adolescents have recently received increasing attention in the scientific literature.
Seven published, randomized efficacy trials for primary adult marijuana abuse and dependence have consistently demonstrated that outpatient treatments can reduce marijuana consumption and engender abstinence. The most commonly tested interventions are adaptations of interventions initially developed to treat alcohol or cocaine dependence, in particular MET and CBT (also known as coping skills training). Recently, trials have examined the use of CM to enhance the potency of MET- and CBT-based treatments. The cumulative findings indicate that (1) each of these interventions represents a reasonable and efficacious treatment approach; (2) the combination of MET and CBT is probably more potent than MET alone; and (3) an intervention that integrates all three approaches—MET, CBT, and CM— is most likely to produce positive outcomes, especially as measured by rates of abstinence from marijuana.
WEB LINKS TO TREATMENT MANUALS Brief Counseling for Marijuana Dependence
(Steinberg et al., 2005
The Motivational Enhancement Therapy and Cognitive Behavioral Therapy for Adolescent Cannabis Users: 5 Sessions,Volume 1. NCADI number BKD384.
The Motivational Enhancement Therapy and Cognitive Behavioral Therapy Supplement: 7 Sessions of Cognitive Behavioral Therapy for Adolescent Cannabis Users,Volume 2.
Family Support Network for Adolescent Cannabis Users,Volume 3.
The Adolescent Community Reinforcement Approach for Adolescent Cannabis Users,Volume4.
Multidimensional Family Therapy for Adolescent Cannabis Users,Volume 5. ncadistore.samhsa.gov/catalog/Product Details.aspx?ProductID=15868.
MET addresses ambivalence about quitting and seeks to strengthen motivation to change. A typical MET regimen consists of one to four 45- to 90-minute individual sessions. Therapists use a nonconfrontational counseling style to guide the patient toward commitment to and action toward change. Therapeutic techniques include using strategic expression of empathy, reflecting, summarizing, affirming, reinforcing self-efficacy, exploring pros and cons of drug use, rolling with resistance, and forging goals and plans to achieve them. An online manual, Brief Counseling for Marijuana Dependence, describes the use of MET intervention with adult marijuana users.
CBT focuses on teaching patients skills relevant to quitting marijuana and avoiding or managing other problems that may interfere with good outcomes. Patients learn functional analysis of marijuana use and cravings, self-management planning to avoid or cope with drug use triggers, drug refusal skills, problem-solving skills, and lifestyle management. CBT for marijuana dependence is typically delivered in 45- to 60-minute, weekly individual or group counseling sessions; tested CBT interventions have ranged from 6 to14 sessions. Each session involves analysis of recent marijuana use or cravings, development of planned responses to situations that may trigger use or craving, brief training on a coping skill, role-playing or other interactive exercises, and practice assignments. Brief Counseling for Marijuana Dependence
describes the content and conduct of CBT sessions in detail (Steinberg et al., 2005
; see “Web Links to Treatment Manuals”).
A series of four trials demonstrated the efficacy of both CBT and MET for adult marijuana dependence (). After an initial trial showed promising results for a CBT group intervention (Stephens, Roffman, and Simpson, 1994
), a second trial tested a 14-session group CBT intervention against 2 individual MET sessions or a delayed treatment control (DTC) condition (Stephens, Roffman, and Curtin, 2000
). At the 4-month followup, the CBT and MET groups had achieved significantly greater rates of abstinence than the DTC group. Days of use, number of uses per day, dependence symptoms, and problems related to use also fell significantly compared with those measures in the DTC group, and gains were generally maintained throughout the 16-month followup. No significant differences were observed between CBT and MET conditions on any of these outcome measures, suggesting that brief motivational interventions may be as effective as longer CBT interventions. However, this study confounded treatment modality (group vs. individual) and therapist experience (provision of MET by more experienced therapists) with treatment length. A similar study showed that a six-session CBT and a one-session MET treatment, both delivered in individual therapy sessions, produced greater rates of abstinence than DTC, but again little difference was observed between the active treatment groups (Copeland et al., 2001
). A positive relation between therapist experience and outcome was reported across both treatment conditions.
Randomized Trials for Adult Marijuana Treatment
The most comprehensive trial (n
= 450) of MET and CBT compared nine sessions of combined MET-CBT with a two-session MET-only intervention and with a DTC (Marijuana Treatment Project Research Group, 2004
). MET-CBT and MET-only again produced better abstinence outcomes than DTC. However, in this trial, MET-CBT was associated with significantly greater long-term abstinence and greater reductions in frequency of marijuana use compared with MET alone. Findings generalized across three sites and were not dependent on ethnicity or gender.
In an effort to enhance outcomes further, researchers have begun to examine the efficacy of CM for treating marijuana dependence (Budney et al., 2001
). The marijuana CM intervention adapts the abstinence-based voucher approach originally developed and demonstrated effective for treating cocaine dependence (Budney and Higgins, 1998
; Higgins et al., 1994
). The vouchers are contingent on marijuana abstinence, confirmed by twice-weekly drug testing, and their value escalates with each consecutive negative drug test. Patients exchange them for prosocial retail items or services that, it is hoped, will serve as alternatives to marijuana use.
An initial trial of CM for adult marijuana dependence compared a 4-session MET, a 14-session combined MET-CBT, and a 14-session MET-CBT plus CM (Budney et al., 2000
). Individuals could earn up to $570 in vouchers if they provided consistently negative urine samples throughout treatment weeks 3 through 14. The MET-CBT plus CM condition produced the highest abstinence rate during treatment. In a second trial conducted to extend these findings (Budney et al., 2006
), 90 adults received MET-CBT, MET-CBT plus CM, or CM alone (no counseling). The magnitude of the CM incentives was identical to that used in the prior study. The MET-CBT-alone intervention differed from the initial study in one regard: vouchers ($5) contingent on providing a urine specimen as scheduled (twice per week) were provided to ensure equivalent retention and treatment contact. This trial produced three notable outcomes. First, MET-CBT plus CM and CM alone both engendered greater initial rates of abstinence than MET-CBT. Second, MET-CBT plus CM produced outcomes that were similar to those of CM alone during treatment, but superior post-treatment.
A recent study by another research group found similar results with a modified CM program (weekly urine testing, $385 maximum voucher earnings for complete abstinence) in a more diverse (40 percent minority) and larger sample (n
= 240; Kadden et al., 2007
). During 7 weeks of treatment, MET-CBT plus CM and CM alone produced continuous abstinence outcomes that were similar to each other and superior to those seen with MET-CBT. During the following year, the MET-CBT plus CM patient group sustained overall positive outcomes somewhat better than those of the CM group, although differences in abstinence rates were not statistically significant at later followups. As in the previous CM trials, patients in the CM and non-CM conditions self-reported similar rates of marijuana use throughout, illustrating the importance of obtaining subjective and objective indices of use. In summary, MET, CBT, and CM each has empirical support for its efficacy, and CM in combination with MET-CBT has demonstrated the most potency in outpatient treatment for adult marijuana dependence, particularly for engendering longer periods of abstinence.
Recognizing that many people overcome dependence only after multiple treatment exposures, Stephens and Roffman (2005)
developed and initially tested a creative, chronic care model of treatment that they termed “marijuana dependence treatment PRN.” Following an initial four sessions of MET-CBT, participants were given the option of determining the number and schedule of treatment sessions they would attend over a 28-month period. The comparison condition in this trial was the same fixed-dose nine-session MET-CBT intervention used in the large multisite trial mentioned earlier (Marijuana Treatment Project Research Group, 2004
). There were three key findings from this trial: (1) A relatively small percentage of participants (37 percent) made use of the continuing care sessions, and (2) the PRN condition overall was not more efficacious than the fixed-dose condition, although (3) the few individuals who attended the greatest number of continuing care sessions (mean of 13.4 sessions) had a high level of 90-day abstinence (approximately 60 percent) at followup.
Adolescents and Young Adults
Most information on marijuana treatment efficacy among young people derives from trials that have included users of various drugs and have not focused specifically on marijuana use. Nevertheless, most patients in these studies have been primary marijuana users. Empirical support for group or individual CBT and family-based treatments has begun to emerge (Waldron and Kaminer, 2004
). The CBT interventions studied have been similar to those studied for adults in scope and duration. Specific forms of family-based treatment that have been tested include functional family therapy (Waldron et al., 2001
), multidimensional family therapy (MDFT; Liddle et al., 2001
), multisystemic therapy (Henggeler et al., 2006
), family support network intervention (Dennis et al., 2004
), and brief strategic family therapy (Azrin et al., 1994
; Santisteban et al., 2003
). Description of these models is beyond the scope of this paper. However, they each involve structured, skills-based interventions for family members and are well described in their respective manuals.
The largest clinical trial of outpatient treatment for adolescent substance abuse focused on marijuana use (Dennis et al., 2004
). Five treatment models were tested in a multisite study: MET-CBT 5 (2 individual and 3 group sessions), MET-CBT 12 (2 individual and 10 group sessions), MET-CBT 12 plus family support network (6 parent education group sessions, 4 home visits, and case management), the community reinforcement approach (10 individual sessions focused on behavioral change in drug use and lifestyle change, and 4 parent sessions focused on effective parenting, communication, and problem solving), and MDFT (12 to 15 family systems-focused sessions: 6 individual, 3 with parents alone, and 6 with family). Significant decreases in drug use and symptoms of dependence were observed following each of the treatments. However, robust between-treatment differences in outcomes were not observed, which unfortunately precludes drawing strong conclusions about their efficacy. Although results were promising compared with prior treatment studies, two-thirds of the youth continued to experience significant substance-related symptoms, suggesting that adolescent treatments can be improved and alternative treatment models should be explored (Compton and Pringle, 2004
As they are doing with treatments for adults, researchers are attempting to enhance youths’ outcomes by adding a CM intervention to MET-CBT-type interventions. Positive results were observed in an initial pilot study of MET-CBT plus a CM intervention that incorporated an abstinence-based voucher program and parent-based CM (Kamon, Budney, and Stanger, 2005
). The voucher program was of the same schedule and magnitude as that used in the previously mentioned adult trials by Budney and colleagues. However, participants could earn vouchers only if urine toxicology screens were negative for all
drugs tested and if parents reported that, to their knowledge, the adolescent had not used any drugs or alcohol. The parenting intervention included a contract that directed parents to provide tangible incentives for abstinence and to deliver negative consequences for continued use. Parents also participated in a weekly behavioral training program called Adolescent Transitions (Dishion and Kavanagh, 2003
), a treatment of choice for adolescents with conduct disorder. Preliminary data from an initial randomized trial suggest that the MET-CBT plus CM improved rates of marijuana abstinence and effectively maintained abstinence post-treatment compared with MET-CBT combined with weekly parent psychoeducational counseling. The rates of abstinence achieved appeared greater than those reported in prior studies; however, comparison across trials is problematic because of differences in patient characteristics and differences in the way outcomes are measured.
Two other tests of CM with adolescents and young adults have produced promising results. A CM abstinence-based voucher program enhanced drug use outcomes and abstinence when added to a potent outpatient therapy (i.e., multisystemic therapy) among juvenile offenders enrolled in drug court (Henggeler et al., 2006
). Lastly, adding incentives for treatment attendance to MET increased treatment participation by young adult marijuana abusers involved with the judicial system, but did not lead to increased marijuana abstinence (Sinha et al., 2003
). In summary, a number of behaviorally based interventions appear efficacious for treating adolescent marijuana abuse, and combining interventions like MET, CBT, CM, and family-based programs is likely to enhance efficacy.
Sufficient evidence has accumulated to conclude that behaviorally based interventions can help many of those who seek treatment for marijuana use disorders. Unfortunately, as with treatment for other dependencies, the rates of “success” are modest. Even with MET-CBT plus CM, the most highly efficacious treatment for adults, only about one-half of those who enroll in treatment achieve an initial 2-week period of abstinence, and among those who do, approximately one-half resume use within a year (Budney et al., 2006
; Kadden et al., 2007
). Across studies, 1-year abstinence rates have ranged between 19 and 29 percent for MET-CBT, and between 9 and 28 percent for MET. An additional percentage of adults report a reduction in use and in problems associated with use; however, many adults show no evidence of progress.
The treatment outcome data for adolescents paint a similar picture. For example, in the large Cannabis Youth Treatment study, abstinence rates at the end of treatment were only 11 to 15 percent (Dennis et al., 2004
; see also the preliminary findings of Dennis and colleagues reported at www.chestnut.org/LI/cyt/findings/index.html
), and rates at 12 months post-treatment, defined by self-report of no substance use in the prior month, were 17 to 34 percent across the five treatments. Clearly, there remains much room for improvement in marijuana outpatient treatment.