Despite a large body of evidence providing overwhelming proof that misuse of cannabis can lead to the typical problems of substance abuse (see for example, Budney AJ, Addiction 2006;101(Suppl. 1):125–133; Budney AJ and Hughes JR, Curr Opin Psychiatry 2006;19(3):233–238), some people continue to question the entire concept of cannabis (marijuana) addiction. With environmental and economic factors such as legalization, concomitant lower costs, and increased drug purity, many fear that addiction to cannabis will become an increasingly larger problem, especially for youth and disadvantaged young adults.

Adults seeking treatment for cannabis use disorder (CUD) typically have been using cannabis on a daily basis for 10 years and report multiple serious attempts to quit. They also report consequences of marijuana use, including relationship problems, financial difficulties, low self-esteem, frustration with their productivity level, sleep and memory problems, and decreased satisfaction with life (Stephens RS et al, Addiction 2002;97 (Suppl. 1):109–124). Most perceive themselves as unable to quit and the majority report that they experience withdrawal symptoms when they try.

Teens and young adults entering treatment do not as readily admit problems related to their cannabis use. Despite this, they are at increased risk for myriad problems: risky sexual behavior, sexually transmitted infections, unplanned pregnancies, low educational achievement, early school drop out, delinquency, and legal entanglements (Tims FM et al, Addiction 2002;97 (Suppl. 1):46–57).

Which Psychosocial Interventions Work?

Generally, CUD responds to the same types of psychosocial therapies that are used for other substance use disorders. These include motivational enhancement therapy, cognitive behavioral therapy, and contingency management. Combining the three modalities seems to yield the best results, particularly if abstinence is the goal.

Motivational enhancement therapy (MET) is a brief (1–4 sessions), non-directive approach delivered in 45–90 minute individual sessions. A carefully planned style of interviewing is designed to address a patient’s ambivalence concerning change and seeks to strengthen motivation to change. Key counseling behaviors include expression of empathy, use of reflection, summarization, affirmation, reinforcement of self-efficacy , change talk, and rolling with resistance. (MET, also called motivational interviewing, was discussed in the Carlat Behavioral Health Report July/August 2012. The article is available for free online at www.carlataddictiontreatment.com.)

Cognitive behavioral therapy (CBT) is typically delivered in weekly individual or group counseling sessions that are 45–60 minutes in duration. The intervention focuses on teaching skills relevant to quitting cannabis and avoiding or coping with problems that might interfere with success. Therapists cover a wide variety of issues: a functional analysis of cannabis use and cravings, coping with triggers, refusal skills, problem-solving, and lifestyle management. Sessions typically involve role-playing or other interactive exercises; patients also receive “homework” assignments.

Abstinence-based contingency management (CM) attempts to increase abstinence through use of tangible reinforcement for documented abstinence (Higgins ST et al, Addict Behav 2002;27(6):887–910). Typical programs provide various incentives contingent on negative urine toxicology, and deliver escalating rewards for longer periods of abstinence as a means for motivating longer-term sobriety. There is much evidence to support the efficacy of CM programs for CUD and other disorders, and manuals to assist with implementation are available (see for example, Stanger C and Budney AJ, Child Adolesc Psychiatr Clin N Am 2010;19(3):547–562).

Although overall effectiveness is difficult to summarize across studies, approximately 5%–10% of patients are abstinent from cannabis six months following treatment with MET. Abstinence increases to 15%–25% with CBT or MET/CBT, and 25%–45% with MET/CBT/CM. Only a few studies have provided an index of clinical improvement, and these suggest that 15%–35% of those receiving MET or CBT could be classified as improved (Peters EN et al, Drug Alcohol Depend 2011;1:118(2–3):408–416; Stephens RS et al, J Consult Clin Psychol 1994;62(1):92–99).

Adolescents and Young Adults

The largest clinical trial for CUD evaluated five, manualized, empirically-based, outpatient treatments for teens (Dennis M et al, J Subst Abuse Treat 2004;27(3):197–213):

1) MET/CBT5 (two individual and three group sessions)

2) MET/CBT12 (two individual and 10 group sessions)

3) MET/CBT12 plus a family support network (six parent education sessions, four home visits, and case management)

4) The community reinforcement approach (10 individual sessions and four parent sessions)

5) Multidimensional family therapy (six individual sessions, three sessions with parents, and six sessions with both)

Significant decreases in cannabis use and symptoms of dependence were observed across treatments, however, no between-treatment differences were clearly observed. Outcomes were superior to prior studies. However, nearly two-thirds of teens continued to report significant problems related to substance abuse.

Other family-based treatments that have been tested include functional family therapy (Waldron HB et al, J Consult Clin Psychol 2001;69(5):802–813), multisystemic therapy (Henggeler SW et al, J Consult Clin Psychol 2006;74(1):42–54), brief strategic family therapy, (Szapocznik J and Williams RA, Clin Child Fam Psychol Rev 2000;3(2):117–134) and CM-based behavioral therapy that includes parent training (Stanger C et al, Drug Alcohol Depend 2009;105(3):240–247). All of these approaches have shown promise in clinical trials and some have already been translated into routine clinical practice.

Only a few studies have been published on treatments specifically for young adults. Findings appear consistent with the literature on adults and teens in that MET, CBT, CM, and combinations thereof are effective. The most potent interventions integrate CM into the overall plan of care (Sinha R et al, Am J Addict 2003;12(4):314–323; Carroll KM et al, J Consult Clin Psychol 2006;74(5):955–966).

Harm Reduction?

Many patients enrolled in treatment for cannabis are seeking to moderate their use, not to quit completely (Lozano BE et al, Addiction 2006;101(11):1589–1597). Unfortunately, little empirical evidence exists about harm reduction approaches for CUD. Harm reduction does not seek abstinence per se. It focuses on reducing harm associated with substance use (Roffman RA and Stephens RS. Harm reduction and cannabis. In: Marlatt GA et al, eds. Harm Reduction: Pragmatic Strategies for Managing High-Risk Behaviors, second edition. New York, NY; Guilford Press, 2012:160).

Among the many unanswered questions are “safe” limits for use and appropriate patient selection for a harm reduction strategy. High quality research is desperately needed to inform future clinical and policy decisions.

Despite evidence of their effectiveness, it should be noted that many people experiencing problems related to cannabis misuse do not have access to these types of interventions. Advances in technology that can enhance access, reduce cost, and perhaps enhance efficacy offer a promising avenue to bring these tools to more people who need them (Marsch LA and Dallery J, Psychiatr Clin North Am 2012;35(2):481–493).

CATR’s Take: A number of effective psychological treatments exist for cannabis addiction. Most office-based clinicians could probably implement motivational enhancement therapy with or without CBT. Contingency management, which is more logistically demanding, is probably better suited for addiction treatment programs. Unfortunately, many patients resume cannabis use despite these interventions.