REVIEWARTICLE

Assessing Marijuana Use in Bariatric Surgery Candidates:Should It Be a Contraindication?

Christina M. Rummell & Leslie J. Heinberg

# Springer Science+Business Media New York 2014

Abstract Research has demonstrated negative effects of bothalcohol and tobacco use after bariatric surgery. However, noresearch to date has examined effects of cannabis use afterbariatric surgery, even though cannabis is the most commonlyused illicit drug in the USA. Literature review reveals thatmany practitioners generalize from data regarding alcoholabuse to all substances. Further, many screening protocols failto differentiate between varying levels of cannabis use. Thecurrent report aims to (1) review the relevant literature onmarijuana use and its potential consequences among bariatricpatients, (2) discuss relevant problems and gaps in this litera-ture, and (3) make preliminary recommendations regardingthe assessment and treatment planning of bariatric candidateswho disclose marijuana use.

Keywords Bariatricsurgery .Weight losssurgery .Cannabis .

Marijuana . Substance use disorder . Illicit drug use .

Recommendations

Introduction: Criteria forWeight Loss SurgeryCandidateSelection

Substance abuse as a contraindication for weight loss surgerywas first noted by the National Institute of Health (NIH) intheir (1991) Consensus Statement [1] and has continued as a

contraindication in published guidelines [2]. This prohibitionmay be because negative post-operative health complicationsare hypothesized to result from abuse of substances both pre-and post-operatively or because of the belief that such useportends other domains of non-adherence.

Regarding specific substances, clinical guidelines havediscussed the clear negative effects of both alcohol and nico-tine use after surgery [2-4]. For example, alcohol use can leadto weight regain, liver damage, dehydration, malnutrition, andulcers after surgery [5]. Post-surgically, patients are signifi-cantly more sensitive to the effects of alcohol [6, 7], and morerecent work suggests an increased risk of alcohol use disordersfollowing surgery—particularly Roux-en-Y gastric bypass(RYGB) [8, 9]. In the American Association of ClinicalEndocrinologists/The Obesity Society/American Society forMetabolic and Bariatric Surgery (AACE/TOS/ASMBS) 2013clinical practice guidelines for bariatric surgery, it is recom-mended that patients eliminate all alcohol consumption post-surgically [2].

In a similar vein, tobacco use increases the risk of deathassociated with bariatric surgery and increases the risk ofdeveloping post-surgical complications such as marginal ul-cers and infection, and tobacco users tend to require more painmanagement after surgery [10]. The AACE/TOS/ASMBSguidelines suggest abstinence from tobacco products for6 weeks prior to surgery, though some report that an evenshorter time period is also acceptable [2].

Regarding the effects of other illicit drugs on surgicaloutcomes, there is some evidence that cocaine use can causevasculitis leading to both ischemic and hemorrhagic strokes[11]. There is one published case study of an 18-year-oldfemale RYGB patient who had used cocaine pre- and post-surgery and evidenced a stroke 4 months post-surgery. How-ever, no definitive evidence was found upon medical exami-nation to link the cause of the stroke to drug use [12]. Theeffects of other substances are largely undescribed.

C. M. Rummell : L. J. HeinbergBariatric and Metabolic Institute, Cleveland Clinic Foundation, 9500Euclid Avenue/M61, Cleveland, OH 44195, USA

C. M. Rummelle-mail: rummelc@ccf.org

L. J. Heinberg (*)Lerner College of Medicine, Cleveland Clinic Foundation, 9500Euclid Avenue/M61, Cleveland, OH 44195, USAe-mail: heinbel@ccf.org

OBES SURGDOI 10.1007/s11695-014-1315-x

According to national statistics, cannabis (marijuana) is themost commonly used illicit drug in the USA, and its useamong young people has been increasing since 2007 [13]. Inlight of some states legalizing the use of marijuana, socialacceptability of its use is also increasing [14]. Further, somephysician researchers have begun to examine the benefits ofmarijuana used in a medical capacity [15-17]. Given thesechanges, a discussion of marijuana use in bariatric surgerypatients is timely.

No empirical research to date has examined the effects ofcannabis use after weight loss surgery. A review of the obesitysurgery literature revealed that many practitioners generalizefrom data regarding alcohol abuse to all substances, collectingit under the category “substance abuse” [4, 18-20]. Further,even in studies that do differentiate, cannabis is often includedin a category such as “illicit drugs.” This is problematicbecause it does not differentiate between a recreational ormedical marijuana user and a heroin or crack cocaine abuser.This practice can be misleading, as the physiological andpsychological effects of one substance are not necessarilygeneralizable to others [21], and frequency and intensity ofuse are likely to be important factors [22].

Despite a lack of empirical research, many weight losssurgery programs require a sustained period of total absti-nence from all illicit drugs prior to approval for surgery.According to a survey of mental health professionalsconducting bariatric evaluations, current illicit drug use wascited as a definite contraindication to surgery in 88.9 % ofprofessionals and a possible contraindication in an additional8.6 %, making it the top cited contraindication out of 37 items[23]. Further, in the same study, history of illicit drug usewithin the past 5 years was marked as a definite contraindica-tion by 30.9 % of the sample. However, all illicit drugs wereconsidered together in this survey so it is unclear if practi-tioners delineate between various substances or severity ofuse. In contrast, although there are documented medical com-plications of both tobacco and alcohol use after weight losssurgery, only 37 and 3.7 %, respectively, of respondentsmarked these as definite contraindications to surgery. Thereis a risk that provider subjectivity and value judgments, ratherthan empirical data, may affect these types of ratings.

Some weight loss surgery programs have developed theirown protocols for assessing and determining candidacy basedon substance use. For example, at the Cleveland Clinic Bar-iatric and Metabolic Institute (CCBMI), patients complete anonline pre-screening questionnaire prior to becoming enrolledin the program. Patients who report any drug use within thelast 6 months on this questionnaire are given a non-candidacyletter. Some weight loss surgery institutions, such as CCBMIand Mayo Clinic, require self-reported substance users tomaintain at least 6–12 months of abstinence from illicit sub-stance use, confirmed by negative urine toxicology screens[24, 25]. Further, at CCBMI, patients who demonstrate or

report substance abuse or dependence are referred to chemicaldependency programs and are required to complete theseprograms’ recommendations and demonstrate laboratory-confirmed abstinence before being reconsidered for candidacy[4]. Patients who have any history of problematic substanceuse (but who are not currently using) are required to completeone 90-min substance risk reduction seminar [4].

In light of these protocols, the current paper aims to (1)review the relevant literature on marijuana use and its poten-tial consequences among bariatric patients, (2) discuss rele-vant problems and gaps in this literature, and (3) make tenta-tive recommendations regarding the assessment and treatmentplanning of bariatric candidates who disclose marijuana use.

Marijuana Use: Statistics, Facts, and Side Effects

Prior to making recommendations about marijuana use andweight loss surgery, it is important to have an increasedunderstanding of cannabis. The main psychoactive chemicalin marijuana is delta-9-tetrahydrocannabinol (THC) [13]. Inthe brain, THC binds to specific sites called cannabinoidreceptors (CB1), located on the surface of particular nervecells in the hippocampus, cerebellum, frontal cortex, striatum,and basal ganglia [26]. The resulting overstimulation of thesereceptors can lead to addiction and withdrawal symptomswhen drug use stops [26, 27], thus making marijuana a drugwith the potential for both abuse and dependence.

Contrary to lay beliefs, regular marijuana use has a numberof ill effects on health. Marijuana smoke contains over 400identified chemicals, including irritants and carcinogens sim-ilar to tobacco smoke [28]. Thus, long-term marijuanasmoking is associated with an increased risk of respiratorycomplications, including cough, sputum production,bronchodilation, asthma, bronchial spasms, and wheezing[13, 26, 28-30]. Further, prolonged marijuana use has beenassociated with tachycardia, heart palpitations and arrhyth-mias, increased risk of heart attack and lung cancer, centralnervous system effects, hypertension, nasopharyngeal irrita-tion, antinociception, suppression of the immune system, andincreased appetite [13, 26, 28-31]. In terms of psychologicalcomplications, cannabis use has been associated with depres-sion, anxiety, psychotic symptoms, schizophrenia, impairmentin cognitive and performance tasks, memory and attentionaldeficits (including lower working memory), and other psychi-atric comorbidities [13, 26, 30-34]. Further, these effects arehigher in patients who use cannabis at higher doses, for alonger duration of time, and when use began before the age of15 [34].

However, though controversial, some research has docu-mented the effective use of “medical marijuana” as a treatmentfor a variety of conditions, including nausea, muscle spasms,intraocular pressure of glaucoma, migraines, and other pain

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syndromes [15, 17]. In one case study, medical marijuana (inthe form of dronabinol) was the only successful treatment for apatient experiencing severe intractable nausea after RYGBsurgery [16]. However, use of medical marijuana is not yetlegal in most states [35], and its use has not been approved bythe FDA [13]. It is clear that long-term, regular marijuana usehas many negative effects. However, there is little research tosupport negative effects of short-term or irregular use.

There is, however, some controversy surrounding regulat-ing use of various substances in a bariatric population [2]. Forexample, consumption of caffeine and carbonated beveragesare contraindicated after bariatric surgery, but programs lackeffective ways of monitoring this consumption. Further, pro-grams typically do not deny patients surgical candidacy basedon the consumption of these beverages. Rather, patients areusually provided with informed consent and thorough pre-and post-surgical recommendations; however, the decision tofollow these recommendations is ultimately the patient’s [36].Similarly, most programs rely on patient self-report to assessrecent alcohol use or abuse [18, 37, 38], and 83 % of patientsself-report continuing alcohol use after surgery despite clearrecommendations to abstain [39].

Data on Drug Use in Bariatric Surgery Candidates

Because a diagnostic psychiatric interview is conducted aspart of manyweight loss surgery protocols and data are readilyavailable, several meta-analyses have looked at rates of sub-stance abuse/dependence in bariatric surgery candidates. Un-fortunately, as previously mentioned, many of these analysescombine data on illegal drug abuse with those of alcoholabuse, making it difficult to determine just how many surgerycandidates engage in illegal drug abuse. Further, many ofthese studies combine marijuana use with all other illegal orstreet drugs.

In studies that do not differentiate between alcohol andrecreational drug abuse, lifetime prevalence rates range from16.7 to 32.6 % [20, 37, 38]. Active current abuse rates in thesesame types of studies range from 0 to 22 % [38, 40]. Forstudies that do differentiate, the numbers vary. Rates of life-time illicit drug abuse prevalence range from 12.53 to 16.0 %[19, 37]. Current or past year prevalence rates are less than2 % [19, 37]. These statistics generally indicate a greaterlifetime prevalence of substance abuse or dependence in bar-iatric patients than in the general population (which is approx-imately 14.6 %), but a lower current prevalence [37].

Regarding cannabis abuse specifically in bariatric popula-tions, one study noted 3.3 % of their sample to be in fullsustained remission from cannabis abuse/dependence [38].Another study noted a lifetime cannabis abuse/dependencerate of 2.9 % [41]. When rates for lifetime cannabis abuse/dependence are considered independently of other substances,

they are much lower in bariatric candidates than in the generalpopulation (3.1 vs 8.5 %, respectively) [42]. As can be seen,rates of cannabis abuse/dependence are strikingly differentthan overall rates of substance abuse/dependence in bariatriccandidates. Therefore, generalizing across all types of sub-stances can be misleading.

Further, different researchers have used different criteria todetermine the presence of a substance use disorder. Substanceuse disorder was originally defined by the Diagnostic andStatistical Manual of Mental Disorders, Fourth Edition, TextRevision (DSM-IV-TR) as either abuse or dependence [43].However, DSM-V has eliminated separate diagnoses, andthese two disorders are now subsumed under one label, “sub-stance use disorder.” Diagnosis is made on a continuum frommild to severe. According to the American Psychiatric Asso-ciation, “in this overarching disorder, the criteria have not onlybeen combined, but strengthened” [44]. In DSM-IV-TR, adiagnosis of substance abuse required only one symptom.However, mild substance use disorder in DSM-5 requirestwo to three symptoms (from a list of 11 possible).

At the time of this writing, research publications still referto abuse and dependence as separate disorders. However, aspreviously stated, the criteria used to determine these disor-ders have varied. For example, one study indicated that 15 oftheir participants had past substance abuse/dependence [38].However, it is not known what type of screening questions, ifany, were asked of these patients in order to determine asubstance use disorder history. Another group of researcherscompared data for patients given a structured clinical inter-view for DSM-IV disorders (SCID) and a semi-structureddiagnostic clinical interview [41]. Results showed that therewas only “fair agreement” in substance use diagnoses betweenthese two assessment mechanisms (kappa coefficient=.36).Over each category of substance use disorder (alcohol, can-nabis, or stimulant), more patients were diagnosed with cur-rent or past substance use disorders by those clinicians usingthe SCID than those using a semi-structured clinical interview.These data show that there can be wide variability in assess-ment mechanisms for substance use disorders. This isconcerning given the tendency of weight loss surgery pro-grams to consider substance use disorders or any currentsubstance use as a contraindication for bariatric surgery.

Is Cannabis Use a Contraindication for SurgicalOutcomes?

Unfortunately, because data of all categories of substanceabuse are typically analyzed collectively, there is no isolateddata regarding surgical outcomes for historical cannabisabusers. However, there is a small amount of data examiningsurgical outcomes in samples of patients with a history ofuncategorized substance abuse versus those without. In a

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few studies, patients who successfully completed substanceabuse treatment actually had higher post-operative weight lossthan patients with no substance abuse diagnoses [24, 45, 46].Interestingly, in one sample of female weight managementpatients, lower rates of past year marijuana use were actuallyassociated with higher BMI [47].

In the larger substance abuse literature, proximal cannabisuse is associated with a greater risk for relapse of othersubstances such as alcohol and other illicit drugs [30]. Theliterature on health effects of prolonged, regular cannabis usealso reveals that it may affect body regions or systems thatcould also be the sites of post-operative complications frombariatric surgery. For example, potential side effects of weightloss surgery include the following: pulmonary embolism,bleeding, infection, and tachycardia (as a sign of anastomoticleak) [48]. Cannabis use can cause increased heart rate, respi-ratory problems, hypertension, and increased risk of infectiondue to immune suppression. Thus, there may be a hypothe-sized potential for cannabis use to exacerbate post-surgicalcomplications; however, this remains undocumented in themedical literature. On the contrary, cannabis may have thepotential to have a lower impact on the body after bariatricsurgery, as it is highly lipophilic [49]. It is clear that moreresearch is needed.

There is evidence that THC, the active ingredient in mar-ijuana, increases feelings of hunger [13]. This is becauseTHC’s effects are similar to those produced by endogenouscannabinoids, naturally occurring chemicals in the brain andbody [13]. Endocannabinoid signals amplify sensory pleasurein limbic system structures associated with hunger and plea-sure [50], increasing the likelihood of overconsumption [51].This could be problematic as the goal of weight loss surgeryprocedures is to restrict food intake. Paradoxically, currentresearch has actually demonstrated a lower prevalence ofobesity in cannabis users as compared to non-users [52-54].As an explanation, some have hypothesized that food anddrugs compete for reward sites in the brain [55]. This mayalso explain the increased risk of alcohol use disorders afterbariatric surgery [56].

Probably the most often cited reason for concern aboutlifetime illicit drug use in bariatric surgery candidates is thepotential for what the popular media calls “addiction transfer.”This term refers to the assumption that the patient’s obesitywas the result of an “addiction” to food and that this addictionmay take a different form once the patient’s eating patterns arealtered by bariatric surgery [57]. Although eating reciprocallyaffects the same neurological reward systems as addictivesubstances [50, 51], there is no consensus in the scientificcommunity that food in general can qualify as an addictivesubstance [44, 57, 58]. Research on both humans and animalssuggests the possibility that addiction may develop to somespecific foods (e.g., those high in sugar and/or high in fat) for acertain phenotype of patient [59, 60]. DSM-V has included a

new category on behavioral addictions; however, gambling isthe only listing at the current time [44] (recently, Gearhardtand colleagues [60] designed the Yale Food Addiction Scaleto assess for food addiction symptoms in young adults; how-ever, it has yet to be widely employed). What can be assumedfrom current research is that patients who struggle with over-eating and/or substance abuse score lower on indices thatmeasure impulse control [61]. However, it is important to notethat no consistent relationship has been found between partic-ular personality traits and WLS outcomes [40, 62-64]. Thus,although food addiction and addiction transfer have receivedmuch lay attention, it has not been found to be an empiricallysupported diagnosis at the current time. Further, there is a lackof empirical evidence to suggest a link between cannabis useand chronic overeating.

Recommendations

While there are documented negative health effects ofchronic, regular cannabis use, there is limited literatureon potential negative side effects of recreational, proximaluse. Although recreational users might be at a lower riskfor detrimental health effects than chronic cannabis users,some research has demonstrated that long-term health ef-fects may arise even in recreational users. For example,Battistella and colleagues found that significant gray mat-ter volume reduction occurred in recreational cannabisusers when use began in adolescence [33]. Weekly canna-bis use has predicted approximately a twofold increase inrisk for later depression and anxiety in users [34]. It ispossible that recreational cannabis use may have greaterdetrimental effects in younger populations, as it interactswith cerebral maturation [33].

As recommended by Sogg, measures of substance useshould “quantify behaviors in a reliable and detailedfashion, make clear distinctions between normative andmaladaptive consumption…and avoid subjectivity andvalue judgments” [57]. In a research context, some havedifferentiated low (less than once per week), medium (atleast weekly), and high (four or more times per week)levels of cannabis use [65]. Other researchers haveattempted to separate non-problematic cannabis use fromproblematic use, with an average use of weekly or lessbeing considered non-problematic [21, 67]. However,there is no official consensus to date regarding theselevels of use. Therefore, weight loss surgery programsmay choose to re-examine their screening protocol and/orcandidacy criteria in light of this information. The rec-ommendations presented in Table 1 are preliminary andare made to assist in this process until future researchprovides more data.

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Additional Considerations

At the current time, there are a myriad of unanswered ques-tions regarding substance use and bariatric patients. Furtherresearch is needed on the effects of cannabis use on bariatricsurgery outcomes, as well as on the weight loss patient ingeneral. Little is known about the medical risks of the variouschemicals present in marijuana. Further, longitudinal researchis needed to investigate whether there are differences in out-comes between chronic cannabis users and occasional, recre-ational users. This research could evaluate long-term effects ofcannabis use in states where recreational use of marijuana islegal. Clinicians also must consider the consequences of cre-ating more rigorous selection criteria: potential loss of

candidates [25, 68], the health costs of not having the surgeryversus the risks of the surgery, and patients underreporting orwithholding information about their use in the psychologicalinterview for fear of being denied surgery.

Conclusion

While considerable research has documented the negativeeffects of tobacco and alcohol use on bariatric surgery pa-tients, little is known about the effects of cannabis use. How-ever, many programs misleadingly generalize from data ontobacco and alcohol to other illicit substances such as mari-juana. This report has outlined what is known about cannabis

Table 1 Recommendations forassessment and treatment plan-ning for bariatric patients whodisclose substance use

Recommendation Example(s) and comments

1. Independently assess and document use of differenttypes of substances (alcohol, tobacco,marijuana, other illicit drugs, misuse ofprescription medications)

Alcohol abuse should not be subsumed under ageneral category of “substance abuse”

2. Be specific in assessment of substance use,documenting duration, frequency, date of lastuse, presence of tolerance or withdrawalsymptoms, and level of impairment infunctioning for each substance

Brief screening measures such as the DSMGuidedCannabis Screen [22] or the Cannabis UseProblems Identification Test [67] may also beemployed

3. Urine toxicology screenings are recommended as asupplement, but not a replacement, for self-report regarding substance use or abstinence

Some research has shown that using self- reportscreening questions are more effective thanurinary analysis for predicting remission ofcannabis use disorder [69]

4. Develop specific, separate treatment protocols foralcohol abuse, nicotine/tobacco abuse, anddifferent types of illicit drug abuse

See Heinberg, Ashton, and Coughlin [4]

5. Develop specific, separate protocols for chronicsubstance abuse/ dependence and recreational,non-abusive use

Create cutoffs along a continuum for level of userather than using dichotomous categories (uservs non-user). This will become more relevant inlight of changing DSM-V criteria

6. For patients who do report irregular recreationalmarijuana use, or more recent problematic use,the employment of informed consentdocuments may be helpful

Patients acknowledge that they have been fullyinformed about the risks of potential drug andalcohol use after surgery (see Heinberg, Ashton,and Coughlin [4])

7. For patients who have a history of non- adherence,the use of a behavioral contract may be helpful.A behavioral contract “spells out in clear termsthe behavioral expectations of the team, andpatients sign their agreement to thoserecommendations” [4]

These contracts typically use stronger languagethan an informed consent document and mayinclude agreements to engage in other risk-reduction behavior, such as urine toxicologyscreenings or engagement in a chemicaldependency program

8. Patients assessed to be at increased risk forsubstance abuse or dependence may be requiredto attend a planned treatment intervention

CCBMI developed a 90-min group interventiontitled, “Substance Risk Reduction Group.” Thegroup session consists of psychoeducation anddiscussion about the effects of substances aftersurgery. Warning signs of addiction arediscussed, and local and national resources foraddiction services are provided as handouts (seeHeinberg, Ashton, and Coughlin [4])

9. Bariatric surgeons, nutritionists, nurses,psychologists, and other professionals shouldsystematically work in close collaboration withspecialists in the field of addiction

Clinical consultation with addictionologistsregarding specific patient issues and involvementin treatment protocol planning

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use in bariatric surgery populations and has provided sometentative recommendations regarding the assessment of can-nabis use in pre-surgical candidates. When making decisionsregarding the candidacy of a potential patient, providers mustalways weigh the risks versus benefits of the weight losssurgery intervention.

Conflict of Interest The first author, Christina M. Rummell, has noconflict of interest to disclose. The second author, Leslie J. Heinberg, hasno conflict of interest to disclose.

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