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Relapse is common in substance use disorders (SUDs), even among treated individuals. The goal of this article was to systematically review the existing evidence on mindfulness meditation-based interventions (MM) for SUDs.
The comprehensive search for and review of literature found over 2,000 abstracts and resulted in 25 eligible manuscripts (22 published, 3 unpublished: 8 RCTs, 7 controlled non-randomized, 6 non-controlled prospective, 2 qualitative studies, 1 case report). When appropriate, methodological quality, absolute risk reduction, number needed to treat, and effect size (ES) were assessed.
Overall, although preliminary evidence suggests MM efficacy and safety, conclusive data for MM as a treatment of SUDs are lacking. Significant methodological limitations exist in most studies. Further, it is unclear which persons with SUDs might benefit most from MM. Future trials must be of sufficient sample size to answer a specific clinical question and should target both assessment of effect size and mechanisms of action.
According to the United Nations Office on Drugs and Crime,(1) approximately 200 million people worldwide are current drug users. In the U.S., an estimated 22.6 million were diagnosed with substance dependence or abuse in 2006.(2) The cost of drug abuse worldwide, in terms of crime, loss of work and health care costs, was estimated at 180.9 billion USD in 2002.(3) The human suffering related to substance use disorders is immeasurable.
Substance use disorders (SUDs) have been described as "chronic relapsing conditions," with rates of relapse exceeding 60% and being relatively consistent across substances of abuse.(4–6) A range of treatments have been developed to target relapse. Among behavioral interventions, cognitive behavioral therapy (CBT), including relapse prevention,(7) has received considerable support. However, in spite of best "standard of care" therapy, relapse rates continue to be high, highlighting the need for development of new treatment modalities to better assist individuals in their recovery.
The theoretical framework for mindfulness meditation suggests that it may be a promising approach to treating addictive disorders.(8,9) Mindfulness has been defined as the intentional, accepting and non-judgmental focus of one's attention on the emotions, thoughts and sensations occurring in the present moment.(10) Such a purposeful control of attention can be learned through training in techniques such as meditation.(11) The "observe and accept" approach, characteristic of meditation, refers to being fully present and attentive to current experience but not being pre-occupied by it. Thus, meditation can become a mental position for being able to separate a given experience from an associated emotion,(12) and can facilitate a skillful or mindful response to a given situation.(8) Meditation is often contrasted with everyday, habitual mental functioning or being on "auto-pilot." As such, meditation may be a valuable technique for SUD-affected persons, whose condition is often associated with unwanted thoughts, emotions and sensations (e.g. craving), the tendency to be on "auto-pilot", and pre-occupation with the “next fix”, rather than "being in the present moment." Meditation may also be a component of maintaining lifestyle balance, with meditation-acquired skills complementing and enhancing CBT effects for SUDs.(7,8,13,14)
Traditionally, meditative techniques have been taught and practiced through formal and in-formal meditation centers. More recently, meditation has also become a component of many therapeutic programs; in 1997, over 240 meditation programs were a part of U.S. health care systems,(15) and the basics of meditation are taught in many U.S. medical schools. Mindfulness Based Stress Reduction (MBSR) (10) is the most frequently cited method of mindfulness training in the medical context.(16) Based on the MBSR model, other therapies, combining both mindfulness and CBT elements have been developed, including the Mindfulness Based Cognitive Therapy (MBCT) for relapse related to recurrent depression (17) and Mindfulness Based Relapse Prevention (MBRP) for relapse related to SUDs.(9,18) Mindfulness is also a central part of Dialectical Behavior Therapy (DBT) for individuals with borderline personality disorder,(19) Acceptance and Commitment Therapy (ACT) (20) for individuals with a variety of mental health problems, and Spiritual Self-Schema (3-S) therapy designed for clients with SUDs.(21)
While the use of mindfulness meditation as a therapy for SUDs is not new and has been associated with anecdotal clinical success,(14) until recently there has been a paucity of research to support its empirical efficacy. The growing interest in complementary and alternative medicine (CAM), especially mind-body therapies,(15,22) has brought a surge of interest in research evaluating the effects of meditation in a range of clinical contexts, including addictive problems. The current evidence on the clinical applications of mindfulness meditation for SUDs has not been rigorously reviewed.
The goal of this article was to systematically review and assess the existing evidence on the effects of mindfulness or mindfulness meditation based therapies for addictive disorders. Although there are various forms of meditation, it is not known whether these approaches have similar effects on the problems or disorders under consideration. This review focused specifically on mindfulness meditation, and the term "meditation", as used in this manuscript, refers exclusively to mindfulness meditation.
Inclusion criteria: 1) study intervention was mindfulness or mindfulness meditation-based (MM), 2) used as a therapy for substance use, misuse or related disorders; 3) the study was longitudinal, with pre- and post-intervention assessments; and 4) it involved human subjects. Exclusion criteria: 1) lack of a sufficient description of the study intervention to determine if it was rooted in mindfulness; 2) non-English; and 3) only interim results of an unpublished study were available. We anticipated that the number of eligible studies would be limited; therefore, we did not exclude studies based on design (experimental vs. non-experimental), methodological quality or specific intervention protocol. Both published and unpublished reports were eligible for inclusion.
The research librarian (RK) worked closely with the co-authors (AZ, KK) to refine search strategies. Comprehensive searches (Table 1) were conducted through Mar 9, 2008 of the following electronic databases: Cochrane Database of Systematic Reviews (since 1995), EMBASE (since 1993), PubMed (including PreMed and Old Med, since 1950), PsycINFO (since 1967), CINAHL (since 1982), and Allied and Complementary Medicine (since 1985). The National Institutes of Health (NIH) CRISP electronic database of relevant institutes (National Institute on Alcohol Abuse and Alcoholism, National Institute on Drug Abuse, National Institute of Mental Health, National Center for Complementary and Alternative Medicine) was searched from 1995 – Mar 9, 2008 with keywords: “meditation” OR “mindfulness”. The Scientific Research on The Transcendental Meditation® Program: Collected Papers (Volumes 1 to 4) were hand-searched. The reference lists of relevant articles were reviewed to identify potentially eligible studies. E-mail or phone contact was attempted with relevant author(s) or Principle Investigator(s) of included articles or abstracts when additional information was needed.
The titles and abstracts of all identified studies were screened (RK and AZ, “initial screening”). Studies that clearly described using only Transcendental Meditation, Progressive Muscle Relaxation, Biofeedback or Autogenic Training as their interventions were excluded. The full-text of studies describing the use of meditation, mindfulness, relaxation, yoga, breath practices or other techniques that were compatible or potentially compatible with mindfulness meditation (as the primary or comparison interventions) were then reviewed (AZ, “secondary screening”). Practices that were included as compatible with MM are described in the following section. The secondary screening resulted in an exclusion of ineligible articles (AZ); articles that were considered potentially eligible were then additionally reviewed (“tertiary screening”) by 3 independent reviewers (NC, GAM, KK), experts in psychology, meditation and relapse prevention for SUDs.
Data from all eligible articles were extracted, and the methodological quality of controlled and prospective case series studies was assessed for internal validity by two unblinded reviewers (AZ, DR). We used an adapted version of a scoring instrument suited for studies using behavioral interventions and developed for the systematic review of alcohol treatment trials.(23) This instrument (Table 2) was adapted for use in SUDs with input from Dr. William Miller, co-developer of the original scale (personal communication, Mar-Apr, 2008).
Using this instrument, the studies were assigned the following sub-scores (Table 3): a) Population Severity Rating (PSR), b) Methodological Quality Score (MQS), c) Clinical Benefit Score (CBS, called the Outcome Logic Score in the original scale (23)), and d) Cumulative Evidence Score (CES), where: CES = CBS x MQS. e) The Overall CES was also calculated for subgroups of studies (e.g., RCTs), as a sum of CES of individual studies.
When possible, absolute risk reduction (ARR), number needed to treat (NNT) and effect size (ES) were calculated by the authors (AZ, DR) for the main substance-use related outcomes. The following formulas were used: a) ARR = absolute difference in outcome rates between the control and treatment groups; b) NTT = 1/ARR; and c) ES, Cohen’s d, was either converted from correlations (where r=0.37 corresponded to d=0.8, r=0.24 corresponded to d=0.5, and r=0.1 corresponded to d=0.2) or calculated from the mean values (M) and standard deviations (SDs); Cohen’s d for controlled trials (formula #1) was calculated as d = [M1 – M2] / SDpooled, where M1, M2 were the means in the two groups, and SDpooled = √ [(SD12 + SD22)/2]; Cohen’s d for uncontrolled pre-post trials (formula #2) was calculated as d = [mean of the pre-post difference] / [SD of this mean]). In cases where it was not possible to use formula #2, then formula #1 was used.
The search identified 1,095 abstracts of published articles. After removing 595 duplicates (RK), 500 abstracts were reviewed (AZ, initial screening). Of those, 276 were excluded. The full-texts of 224 articles were then reviewed (AZ, secondary screening), and 34 articles were submitted for a tertiary screening. Twelve of the 34 articles (24–35) did not meet the eligibility criteria and were excluded. Of the excluded studies, two deserve an additional comment.(24,34) Both studies used the body scan technique as a study intervention. Although the body scan was derived from a mindfulness meditation-based program, in isolation, this technique did not meet the criteria for mindfulness or mindfulness meditation because MM-based body scan involves not only instructions on paying attention to the various parts of the body, but also encourages focused awareness, without attempt to change or manipulate body sensations, thus promoting non-judgmental and compassionate acceptance of whatever is occurring in the body at any given moment.
The 22 published articles included 7 RCTs,(36–42) 6 controlled non-randomized trials,(43–48) 6 prospective case series,(49–53) 1 case report (54) and 2 qualitative studies.(55,56) Seventeen of these reports were based on separate clinical trials and 5 on secondary database analyses.(45,48,52,55,57) The CRISP database search found 324 “hits,” resulting in 9 additional relevant abstracts. Through personal communication, 2 ready-for-submission, but unpublished articles (58,59) and 1 PhD dissertation (60) were additionally identified as eligible, resulting in a total of 25 included studies. Of note, after completion of this manuscript, results of one of the "unpublished studies" (58) have been published.(61)
The heterogeneity of the included studies and interrater agreement on methodological quality scoring were not formally assessed. The wide variety of conditions treated, treatment protocols and outcome measures used was apparent on inspection, and made the pooling of data impossible. Disagreements between the reviewers were resolved by consensus.
Three studies focused on adolescents,(49,52,57) while the remaining 19 studies evaluated adults. Of the 22 studies, 12 evaluated severely impaired subjects (Population Severity Rating, PSR 4/4), treated for alcohol and/or drug dependence in residential (36,46,51,56) or outpatient settings,(37,40,41,47,53,55,62) three described a clinical sample of adolescents with SUDs (PSR 3/4),(49,52,57) three included a non-clinical sample of substance-using prisoners (PSR 2/4),(44,45,48) and four were based on community-recruited adults (PSR 2/4) with tobacco (38,43,50) or marijuana (54) dependence.
The MM interventions used in the included studies were based on 5 main models:
(http://www.dhamma.org) is a form of MM that is deeply rooted in the Buddhist tradition. Most contemporary forms of MM derive from traditional Vipassana meditation. Typical Vipassana courses are group-based, last ten consecutive days, are conducted in silence, and involve meditating for 10–11 hours per day. They are available at no charge and follow a similar curriculum world-wide.
Three articles,(44,45,48) based on one study,(44) described the effects of a traditional vipassana training led by a traditionally trained teacher, in a prison settings. The intervention was standardized (followed a traditional vipassana format), but its delivery was not monitored.
Originally developed for management of chronic pain and stress-related disorders,(10) MBSR has been shown to be effective or potentially effective for many mental health and medical conditions.(16) MBSR is the most frequently cited method of meditation training in the medical context,(16) and has a published curriculum.(10) The usual MBSR course consists of 8 weekly, therapist-led group sessions (2–2.5 hours per session), one full-day retreat (7–8 hours) and daily home assignments. The MBSR curriculum served as a model for the manualized Mindfulness Based Cognitive Therapy (MBCT) (17) that combines meditation (10) and traditional, cognitive therapy strategies (63) to prevent relapse in recurrent depression. MBCT has been shown to reduce the rate of depressive relapse among persons with recurrent depression,(64,65) and may be efficacious for symptom reduction in "active" depression (66) and anxiety disorders as well.(67) Using the MBCT model in turn, a manualized Mindfulness Based Relapse Prevention (MBRP) program has been developed for outpatient clients with SUDs.(9,18) The elements of cognitive therapy in MBRP are based on relapse prevention cognitive therapy strategies (7) that have demonstrated efficacy for SUDs.(68) Evaluation of the MBRP program for SUDs is currently ongoing.(69)
Ten articles,(36,43,46,49–53,56,57) based on 8 separate studies,(36,43,46,49–51,53,56) reported use of the MBSR-based intervention. Only one study did not report modifications to the MBSR curriculum;(43) the other studies implemented modified MBSR programs, tailored to the targeted population. The modifications were reported as “minor” in 3 studies (46,50,51) – in these studies, the intervention, delivered by trained MBSR teachers, was labeled as "MBSR" and scored as “manualized.” Two studies (four reports: 36,49,52,57) used modified MBSR, with modifications being quite substantial and not manualized – therefore, these interventions were scored as “not manualized.” Two studies developed and used an MBSR-based, manualized intervention: one patterned after MBSR and adjusted to the needs of therapeutic community residents,(56) and one patterned after MBRP and adjusted to the needs of recovering, alcohol dependent adults.(53) The meditation course intensity in the included studies ranged from five 90-minute sessions over seven weeks (with less than 50% of the session content devoted to MM) (49,52,57) to eight 2–2.5-hour sessions over eight weeks, with the majority of each session devoted to MM.(36,43,46,50,53) In addition, two studies implemented a full-day retreat.(36,50) Only one study reported monitoring the integrity of intervention delivery.(56)
therapy has been developed for the treatment of addiction and HIV risk behavior.(21) Its curriculum is manualized (www.3-S.us) and consists of an 8- or 12-week long course, designed for clients at risk for, but not infected with HIV or clients with HIV, respectively. The 3-S therapy teaches meditation and mindfulness skills in the context of comprehensive psychotherapy, integrating Buddhist principles with modern cognitive self-schema theory that is tailored to each patient’s spiritual/religious faith.(21)
Four reports,(37,42,47,55) based on 3 separate studies,(37,42,47) used manualized 3-S therapy delivered in an individual and/or group format, during 1–2 hour-long sessions per week, by a trained therapist over eight (37,42,55) or twelve (47) weeks. Integrity of the intervention delivery was monitored in all the studies.
Theoretically based in contemporary behavior analysis, ACT applies both mindfulness/acceptance, as well as commitment and behavior change processes.(62) These core processes, conceptualized as positive psychological skills, aim to increase psychological flexibility that is defined as the ability to better connect to one’s experience, and to make overt behavioral choices in the service of chosen goals and values (“committed action”).(62) Originally developed for psychological disorders,(20) ACT has been applied to a variety of conditions, including SUDs.
Three studies used manualized ACT,(38,39,54) delivered by a trained therapist in either an individual (54) or both individual and group (38,39) therapy format. The ACT sessions took place weekly, ranging in duration from 1½ (54) to 3½ (39) hours per week, over seven (38) to sixteen (39) weeks. Integrity of intervention delivery was monitored in all the studies.
DBT originated as a therapy for chronically suicidal clients with borderline personality disorder,(19,70) and was subsequently adapted for SUDs.(71) DBT comprises strategies from cognitive and behavioral therapies (with a problem-solving focus) and acceptance strategies (with mindfulness as its core) adapted from Zen teaching and practice. It provides a comprehensive long-term treatment that includes psychotherapy (therapist-led, in group and individual formats), case and medical management.
Two studies used a 1 year-long manualized DBT program for SUDs, with individual and group therapy lasting from three (41) to six (40) hours per week. Integrity of intervention delivery was monitored in these studies.
All 7 RCTs (Table 4) received 4 points for randomization on the MQS scores, including the study that reported unequal effects of randomization (36) – in this case, a full MQS score was assigned since the "unequality" favored the controls. Two of the 7 RCTs used randomization techniques that require a comment. One of these RCTs initially randomized subjects into 2 arms: MM and "standard of care" control, and then sub-randomized the MM group into two different protocols of MM delivery. Since no differences were found between the two MM subgroups, they were later combined into one group for the final analysis, and compared to controls.(42) Another RCT randomly assigned subjects to two different modes of MM delivery, but found no differences between these groups (no details described); thus, the groups were combined into one, and assessed as a prospective case series, with detailed results presented for pre-post analyses only.(37)
"Double-blinding," interventionist or subject blinding are not feasible and/or desirable in studies using MM interventions for practical and ethical reasons, and none of the treatment studies used such methods. Three RCTs reported assessor blinding.(39–41)
The included studies were "pilots" with small sample sizes. One published RCT (39) and one unpublished RCT (59) provided sample size assumptions, however, a high attrition rate resulted in their being underpowered.
Only one study described evaluation of the distributional characteristics of the variables, and the use of parametric or non-parametric tests, when appropriate.(53) One published study (43) and one unpublished study (58) did not use statistical analyses for the assessment of intervention effects. Other studies used parametric analyses that assume normal data distribution. However, in the context of small sample sizes and high variability of some data (as indicated by SDs), it is possible that some variables did not have normal distribution. Six studies either reported 100% follow-up data collection,(50) 100% retention (46) or analyzed data per intention-to-treat (ITT) protocol, imputing missing data.(38–41)
MM was manualized in 15 separate studies, described in 18 articles.(37–48,50,51,53–56) Integrity of the intervention delivery (therapist protocol adherence and/or competence) was monitored in 10 separate studies.(37–42,47,50,54,56)
Among the included 22 reports, 15 were based on separate studies. As expected, among these 15 studies, the highest MQSs were for RCTs, followed by non-randomized controlled trials and case series. Only one RCT (40) received a score of "excellent", defined as MQS ≥ 14.(23) Evaluating by the type of MM intervention used, the highest MQSs were achieved by studies of DBT and ACT, followed by 3-S and MBSR-based therapies. The MBSR-based intervention was the most commonly studied MM therapy (7/15 studies). Grouping by subject population, the highest mean MQSs were achieved by studies evaluating adults with SUDs in the outpatient setting, which were also the most common population / settings (N=7: opiate dependent, medically managed subjects – five studies; poly-SUDs – one study; and alcohol dependence – one study); these studies were followed by studies of community-recruited adults with tobacco dependence (N=3), and studies of adults treated for SUDs in residential settings (N=3). The Overall CES, calculated for subgroups of studies, indicated that, in general, the studies yielded positive evidence (Overall CES ranging from +10 to +143) with 50% to 85% of the studies reporting positive outcomes by ITT (N=6) or per protocol (N=13) analyses, respectively (Table 3).
Seven RCTs, including a total of 383 (63% female) adult subjects, followed for an average of 38 weeks post-entry (from eight (37,42) to sixty eight (40,41) weeks), offered the most detailed assessment of MM interventions. Methodological quality of the RCTs was moderate (MQS 8-14/17). Six RCTs evaluated severely impaired populations (PSR 4/4), and one (38) focused on tobacco dependent adults (PSR 2/4).
Six of 7 RCTs used two-arm, and one used a three-arm design.(39) Three studies compared MM + "standard of care" (SOC) to SOC alone,(36,42) with both MM and SOC provided at the same clinical site. One study compared MM to SOC, with SOC subjects referred out for therapy ("naturalistic control").(41) Finally, four studies (37–40) compared MM to an active intervention: three to a different therapy (behavioral (39,40) or pharmacotherapy (38)) and one compared MM delivered in "individual" versus "individual + group format".(37)
All RCTs reported some positive results. Compared to SOC, the MM intervention showed positive effects as indicated by the ITT (40,41) and per protocol (38–42) analyses. Differential improvement in both substance use-related and other outcomes was noted in 5 of 7 studies.(38–42) One study (36) noted a differential improvement in medical symptom severity only (p<0.05, effect size 0.2), and one study,(37) comparing 3-S "individual" to 3-S "individual + group" therapy did not find differences between the study arms, but noted pre-post improvements (p<0.05, effect size 0.5) in substance use outcomes.
Overall, studies using SOC (39,41,42) or active, but "non-matching" interventions (38) as a comparison group, tended to report greater statistically significant between-group differences, with results favoring MM, than studies using a "matching" behavioral intervention.(39,40) The 3-arm study by Hayes et al.,(39) with the largest sample size but low retention rate, of 124 poly-substance abusing methadone maintenance patients suggested, in a per protocol analysis, that MM + SOC may result in a substantial reduction of substance use compared to SOC alone (ARR 33%). This finding was consistent across 3 other RCTs comparing MM to SOC (ARR 30% (42) with medium to large effect size (41)) or to pharmacotherapy with medical management (ARR 12–20% per ITT and per protocol analyses).(38) Two methodologically strong RCTs compared MM to a different behavioral intervention that "matched" MM by subject involvement and therapy format.(39,40) These studies did not find significant in-between group differences in substance use (ARR 5–12%, p>0.05) or psychological outcomes at the study end-point at forty two (39) or sixty eight (40) weeks, however, they both noted a tendency to a more accurate drug use reporting among MM compared to comparison subjects.(39,40) Regarding non-substance use related measures, MM subjects, compared to SOC controls, increased their motivation for HIV prevention, their spiritual practices and showed a cognitive shift from "addict" to "spiritual qualities" (p<0.05);(42) they also improved their Global Adjustment and Global Social Adjustment Scale scores (p<0.05).(41)
Table 5 summarizes four controlled non-randomized trials (described by 6 articles (43–48)), four case series (described by 6 articles (49–53,57)) and one case report.(54) These studies included 609 subjects, 13 to 67 years old, suffering from various SUDs, and recruited from the outpatient treatment,(46,47,49,51–53,57) community,(43,50) or jail (44,48) settings.
While the methodological quality of the scored studies was limited (MQS 4-8/17), collectively they reported overall positive outcomes. On average, substance use tended to decrease at follow-up compared to baseline (43,50,53) or compared to a control group,(44,47) with effect sizes ranging from small (47,53) to medium.(44) One study (49) reported an increase in substance use at follow-up compared to low-use at baseline, but no detailed results were presented, and substance use was not the primary focus of the study. Severity of potential relapse triggers (such as stress, mental health and sleep problems, certain coping styles) also tended to improve compared to both baseline (49,50,53) and control conditions,(44,46,47) and the average effect size for these changes ranged from medium to large. Bowen et al. (44) also noted a reduction of alcohol-related negative consequences (small effect size) among subjects who underwent MM training compared to controls. Only one uncontrolled trial (among all included studies) of alcoholics treated with MM therapy, adjunctive to SOC, assessed craving severity and the degree of mindfulness.(53) Although craving severity decreased (medium effect size), this change was not statistically significant; degree of mindfulness, or the ability to be attentive to a present-moment experience in daily life, improved (medium effect size), and this change correlated to improved stress severity (large effect size) at 16 week follow-up.(53)
Participation in the MM therapy correlated to or mediated the improvements in substance use and relapse-related outcomes, with small-to-large effect size.(44,45,47,48,50,53) One uncontrolled study compared "relapsers" (N=7; subjects reporting at least one heavy drinking day during the study) to non-relapsers (N=8), and found that relapsers had more severe symptoms of anxiety, depression and craving, reported lower degree of mindfulness and meditated fewer minutes per day (p<0.05).(53) The same study also reported that drinking level as well as the change in drinking correlated to the severity of relapse risk factors such as anxiety, depression, stress, and craving (large effect sizes) and the change in their severity, respectively. In turn, severity of relapse risk factors negatively correlated with the intensity of a daily meditation practice (large effect size).(53)
Two uncontrolled trials assessed pre-post levels of biological outcomes: stress-responsive and illness-sensitive biomarkers, in addition to self-reported psychological measures. A study of recovering alcoholics evaluated serum interleukin-6 (IL-6), liver enzymes and diurnal profile of salivary cortisol at baseline and 16-week follow-up.(53) While cortisol (N=10) and liver enzymes (N=12) did not significantly change over time (small effect size), IL-6 level decreased (N=12; medium effect size, p=0.05), suggesting a reduction in chronic stress level and improved health. After MM intervention, SUD-affected residents of a therapeutic community showed a decrease in an awakening salivary cortisol level compared to baseline (medium effect size).(51)
Two qualitative studies,(55,56) derived from mixed-methods primary projects,(42,47,72) focused on subject treatment experiences related to MM therapy (Table 5). Several other studies also evaluated subject experiences, using quantitative (e.g. Likert scales) or qualitative techniques.(38,39,43,53) Taken together, MM therapy was well-received by the subjects with different degrees of problem severity (PSR 2-4/4) and in various settings: residential,(56) outpatient (39,53,55) and community.(38,43) Subjects reported high degree of satisfaction with MM therapy and its usefulness as a recovery-enhancing tool. They also viewed MM-related skills as unique, "brand new" and different from those taught in a traditional, professional addiction treatment.(53,55)
Four studies evaluated individual ("at-home") MM practices among the subjects who underwent an 8-week MM intervention.(36,42,43,53) Two of these studies, using the MBSR-based intervention, reported that about 47% of the subjects continued meditation practice at twleve (43) and twenty two (36) weeks post-entry. A study evaluating MBSR + CBT-based intervention found that 100% of the study completers (79% of the sample, with all drop-outs occurring after the 1st or 2nd MM session) meditated at 16 weeks, on average 3.9 days/week, 27.4 minutes/meditating day.(53) Likewise, an RCT evaluating 3-S therapy found that at 8 weeks all study completers (82%) continued meditating, on average 26 minutes/day.(42)
Two treatment trials using ACT (58,59) and one laboratory-based study of a mindfulness-based coping technique (60) provide additional insights into the potential efficacy and mechanisms of MM interventions for smoking cessation. An RCT of 10-week MM intervention (ACT, combined with CBT and nicotine replacement therapy, NRT) found a significantly higher quit rate (small effect size) and higher treatment satisfaction (medium effect size) among the MM subjects compared to controls, receiving NRT alone, at 52 weeks; in addition, acceptance-based responding mediated effects of MM on smoking outcomes.(59) A set of prospective case series (N=16 subjects), designed for pilot-testing and refinement of the study methods, evaluated effects of combined ACT, CBT and NRT. Although smoking quantity and frequency have not been compared "pre-post," and all study completers resumed smoking at 26 weeks post-quit date, the longest continuous abstinence period was longer after the MM intervention than during subjects' previous attempts when abstinence had lasted less than 3 days. Further, 82% of the subjects reported that they learned skills that were “very” or “extremely useful” in helping them quit smoking.(58) Finally, one RCT (PhD dissertation) described an experiment evaluating efficacy of mindfulness-based coping compared to "usual" coping strategies aimed to prevent relapse after quitting smoking.(60) In this study, during a cue exposure paradigm, the MM group used MM strategies, as instructed, while controls used primarily distraction-based techniques to cope with smoking cravings and urges. During the 7 day follow-up, the MM group smoked fewer cigarettes/day than controls (medium effect size, p<0.05). Overall, the results of these unpublished trials support the existing preliminary evidence provided by published studies.
This is the first systematic review of mindfulness or mindfulness meditation based interventions (MM) for substance use, misuse or disorders. Although existing data is preliminary and does not allow a consensus recommendation for any particular type of MM intervention for any single substance use-related condition, several findings are of clinical, theoretical and research interest.
The majority of the reviewed studies showed some positive outcomes among SUD-affected subjects treated with MM intervention, compared to baseline or other therapy (most commonly SOC). The case studies illustrated how MM has been practiced from a historical and clinical perspective. The focus on real-life trial methods has been termed pragmatic.(73) Pragmatic studies have the advantage of assessing effectiveness under conditions that patients encounter in real-life settings, thereby avoiding confounders associated with highly standardized clinical trial settings. Though lacking methodological strengths of control and randomization, the case studies, documented here, consistently showed positive patient outcomes and the general treatment satisfaction of subjects with chronic, often refractory, SUDs who were treated with MM therapy. Pragmatic aspects of these studies included meeting patient's expectations of receiving a "promised treatment," the ability of the therapist to better select the patient, and study methods that more closely resemble real clinical settings. Data from the controlled trials suggest that subjects receiving MM, adjunctive to SOC or pharmacotherapy, do as well or better than those receiving SOC or pharmacotherapy alone. When compared to other behavioral interventions in RCT settings, MM appears to produce comparable results. All these conclusions require assessment with more formal methodology in adequately powered clinical trials.
The promise of MM as an efficacious treatment for SUDs is supported by the consistency of positive results, demonstrated in this review across different study designs, MM modalities, subject populations and addictive disorders treated. Additional support for the potential efficacy of MM in SUDs can be drawn from the results of studies of other clinical samples. MM-based therapies have been shown to be effective or potentially effective (with, on average, medium pooled effect size, Cohen’s d 0.5–0.7 (16,62)) for a variety of medical and mental health disorders, including stress, anxiety, depression, emotion dysregulation, avoidance coping,(16,62,74–77) all known risk factors for relapse in SUDs.(78,79) In this context, MM may be particularly helpful for patients with co-occurring substance use and mental health disorders ("dual diagnosis").
Although long-term MM practice patterns have not been assessed in the context of SUDs, its use in other clinical samples suggests that MM can have long-lasting effects. For example, after a meditation course, 60–90% of subjects still meditated up to 4 years later, and reported that the course "had lasting value" and was highly important.(16) Patient satisfaction is an important consideration when choosing between treatment alternatives.(80) MM also appears safe - rigorous studies have not reported any side effects or adverse events.(64,65) This review corroborates these findings.
It is appealing to assume that the preliminary positive results in MM studies are direct outcomes of MM interventions; however, such a hypothesis is premature. The theoretical framework behind MM as well as early indirect evidence supports the use of MM for SUDs (8,9,13,14) and suggests unique therapeutic properties of MM. On a conceptual level, MM stands out as distinctive and, in many ways, different from other existing behavioral modalities, specifically from cognitive behavioral therapy (CBT) that is commonly used to treat SUDs.(81,82) While CBT promotes adaptive, antecedent-focused coping strategies (e.g. targeting emotion cues), meditation targets maladaptive, response-focused strategies, such as emotional avoidance, suppression or impulse control; thus, MM-related skills can complement skills acquired through CBT.(8,9,13,14) The integration of meditation and traditional CBT strategies may improve overall treatment efficacy, e.g. by increasing awareness of sensations, such as craving, emotional states, and physiological arousal.(83) Recent pilot trials of clinical cohorts add support to the above hypotheses, indicating that MM and CBT can produce different effects on mental health outcomes.(62,84,85) Two reviewed qualitative studies (53,55) reported that subjects viewed MM-related skills as different from those acquired through "traditional" SOC therapy for addiction.
of this review include limiting the inclusion criteria to studies published in English, potentially excluding relevant studies. Lack of reviewer blinding and lack of assessment of inter-rater agreement could have introduced bias. Although the included interventions were based on the MM principles, they were heterogeneous; evaluating them together as one "MM intervention" could have introduced bias.
of this review include an exhaustive literature search and application of statistical methods allowing direct comparison of included studies.
Existing studies of MM therapy for addictive disorders are far from definitive and the research methods are evolving. These clinical and research fields would benefit from the development of: 1) standardized scientific parameters to be used in future studies of MM as a therapy for addictive disorders, 2) a comprehensive conceptual model of possible mechanisms underlying MM efficacy in SUDs, and 3) recommendations on MM implementation in clinical addiction medicine settings. Below we elaborate on each of these recommendations:
Conclusive data for MM as a treatment for addictive disorders are lacking. However, the preliminary evidence indicate MM efficacy. MM therapies appear safe when performed in clinical research settings. Significant methodological limitations exist in most studies published to date, and it is unclear which persons with addictive disorders might benefit most from MM. Future clinical trials must be of sufficient sample size to answer a specific clinical question and should include carefully designed comparison groups that would allow assessment of both the effect size and mechanism of action of MM.
This study was supported by two grants from the National Institute on Alcohol Abuse and Alcoholism: 5T32 AA014845—A.Z. (P.I.: Michael Fleming, MD, MPH), and K23 AA017508—A.Z. (P.I.: A.Z.).