New-Onset Substance Use Disorder After Gastric Bypass Surgery: Rates and Associated Characteristics

Bariatric Surgery and New-Onset Substance Use Disorders: A Systematic review and Meta-analysis

Increasing evidence suggests that bariatric surgery (BS) patients are at risk for substance abuse disorders (SUD). The purpose of this systematic review and meta-analysis was to determine the relationship between BS and the development of new-onset substance abuse disorder (SUDNO) in bariatric patients. On October 31, 2023, we reviewed the scientific literature following PRISMA guidelines. A total of 3242 studies were analyzed, 7 met the inclusion criteria. The pooled incidence of SUDNO was 4.28%. Patients' characteristics associated with SUDNO included preoperative mental disorders, high pre-BS BMI, and public health insurance. Surgical factors associated with new SUDNOs included severe complications in the peri- or postoperative period. The occurrence of SUDNOs is a non-negligeable complication after BS. Predisposing factors may be identified and preventive actions undertaken.

Bariatric surgery patients in AUD treatment in Norway-an exploratory cross-sectional study

AIMS

Patients who have undergone some forms of bariatric surgery have increased risk of developing alcohol use disorder (AUD). In the present observational study, we compared patients with AUD who themselves reported to having undergone bariatric surgery with other patients in treatment for AUD.

MATERIALS

One-hundred-and-six consecutively enrolled patients in residential treatment for AUD were asked if they had undergone bariatric surgery. Sociodemographics, mental health-related, and alcohol use-related parameters were compared between those who had and those who had not undergone bariatric surgery.

RESULTS

Of the 106 patients with AUD, seven (6.6%; 95% confidence interval, 2.7%-13.1%) had undergone bariatric surgery. Six of seven patients had undergone such surgery were women (P < .001). The patients with AUD who had undergone bariatric surgery were similar to other patients with AUD on most other parameters, the exception being a larger number of alcohol units ingested to feel an effect of alcohol (adjusted odds ratio 7.1; 95% confidence interval 2.0-12.2; P = .007).

CONCLUSION

The high number of patients with AUD that reported having undergone bariatric surgery emphasizes the risks following such a procedure. The overrepresentation of women may reflect than more women undergo such procedures. The unexpected finding that patients with AUD having undergone bariatric surgery seemed to need more alcohol to feel intoxicated warrants further research.

Opioid Analgesics after Bariatric Surgery: A Scoping Review to Evaluate Physiological Risk Factors for Opioid-Related Harm

The persisting use of opioids following bariatric surgery has emerged as a prevalent complication, heightening the probability of opioid-related harm (ORM), such as opioid-related fatalities and prescription opioid use disorder (OUD). A comprehensive review of PubMed literature from 1990 to 2023 was conducted to pinpoint physiological influences on postoperative ORM. As a result, we found that patients undertaking bariatric operations often exhibit an inherently higher risk for substance use disorders, likely attributable to genetic predisposition and related neurobiological changes that engender obesity and addiction-like tendencies. Furthermore, chronic pain is a common post-bariatric surgery complaint, and the surgical type impacts opioid needs, with increased long-term opioid use after surgeries. Additionally, the subjective nature of pain perception in patients with obesity can distort pain reporting and the corresponding opioid prescription both before and after surgery. Furthermore, the postoperative alterations to the gastrointestinal structure can affect the microbiome and opioid absorption rates, resulting in fluctuating systemic exposure to orally ingested opioids. The prospect of ORM development post-bariatric surgery appears amplified due to a preexisting susceptibility to addictive habits, surgically induced pain, modified gut-brain interaction and pain management and the changed pharmacokinetics post-surgery. Further research is warranted to clarify these potential risk variables for ORM, specifically OUD, in the bariatric population.

Substance abuse screening prior to bariatric surgery: an MBSAQIP cohort study evaluating frequency and factors associated with screening

INTRODUCTION

Patients undergoing bariatric surgery experience substantial risk of pre- and postoperative substance use. Identifying patients at risk for substance use using validated screening tools remains crucial to risk mitigation and operative planning. We aimed to evaluate proportion of bariatric surgery patients undergoing specific substance abuse screening, factors associated with screening and the relationship between screening and postoperative complications.

METHODS

The 2021 MBSAQIP database was analyzed. Bivariate analysis was performed to compare factors between groups who were screened for substance abuse versus non-screened, and to compare frequency of outcomes. Multivariate logistic regression analysis was performed to assess the independent effect of substance screening on serious complications and mortality, and to assess factors associated with substance abuse screening.

RESULTS

A total of 210, 804 patients were included, with 133,313 (63.2%) undergoing screening and 77,491 (36.8%) who did not. Those who underwent screening were more likely to be white, non-smoker, and have more comorbidities. The frequency of complications was not significant (e.g., reintervention, reoperation, leak) or similar (readmission rates 3.3% vs. 3.5%) between screened and not screened groups. On multivariate analysis, lower substance abuse screening was not associated with 30-day death or 30-day serious complication. Factors that significantly affected likelihood of being screened for substance abuse included being black (aOR 0.87, p < 0.001) or other race (aOR 0.82, p < 0.001) compared to white, being a smoker (aOR 0.93, p < 0.001), having a conversion or revision procedure (aOR 0.78, p < 0.001; aOR 0.64, p < 0.001, respectively), having more comorbidities and undergoing Roux-en-y gastric bypass (aOR 1.13, p < 0.001).

CONCLUSION

There remains significant inequities in substance abuse screening in bariatric surgery patients regarding demographic, clinical, and operative factors. These factors include race, smoking status, presence of preoperative comorbidities, and procedure type. Further awareness and initiatives highlighting the importance of identifying at risk patients is critical for ongoing outcome improvement.

Incidence of Substance Use Disorder Following Bariatric Surgery: A Retrospective Cohort Study

BACKGROUND

New-onset substance use disorder (SUD) following bariatric surgery is a significant concern that is likely multi-factorial, although the etiologies are unclear. Previous studies have identified variable rates of SUD along with utilizing different methods and measures. The objective of this study is to evaluate new-onset SUD diagnoses among adults following bariatric surgery and compare these rates to those in the general population as well as those diagnosed with overweight or obesity.

METHODS

Data was extracted from TriNetX Research Platform and used to build three cohorts of adults: those who had bariatric surgery (bariatric surgery cohort), those diagnosed with obesity or overweight, and a general population cohort. Rates of incident SUD were compared among these three groups. Initial encounters for all individuals were from January 1, 2018, to June 30, 2019.

RESULTS

The incidence rate of SUD in patients with a history of bariatric surgery was 6.55% (n = 2523). When compared to the general population, persons who had any type of bariatric procedure had a decreased risk of new-onset SUD with an overall odds ratio (OR) [95% confidence limits (CL)] of 0.89 [0.86, 0.93]. When compared to persons with overweight or obesity, bariatric patients were less likely to develop any form of SUD (OR: 0.65 [0.62, 0.67]).

CONCLUSION

While overall rates of new-onset SUD are lower among those who had bariatric surgery, they also vary by surgery and substance type. Efforts should still be made to address new-onset SUD in order to optimize the post-surgical care of patients.

Emotion regulation in substance use disorders: a systematic review and meta-analysis

BACKGROUND AND AIMS

The ability to regulate emotions effectively has been associated with resilience to psychopathology. Individuals with substance use disorders (SUDs) have been shown to have higher levels of negative emotionality, with some evidence suggesting impairment in emotion regulation compared with individuals without SUDs. However, no previous attempt has been made to systematically review the literature to assess the magnitude of this difference. We aimed to assess the association between SUD diagnosis and emotion regulation as measured by the Difficulties in Emotion Regulation Scale (DERS) and Emotion Regulation Questionnaire (ERQ) through a systematic review and meta-analysis of existing findings.

METHODS

The systematic review was conducted using PubMed, PsycINFO and Embase. We examined cross-sectional studies that compared a SUD group with a control group and measured emotion regulation using the DERS or the ERQ. The primary analysis focused on papers using the DERS, as this was the predominant instrument in the literature.

RESULTS

Twenty-two studies met our primary analysis criteria, representing 1936 individuals with a SUD and 1567 controls. Individuals with SUDs relative to controls had significantly greater DERS scores, with a mean difference of 21.44 [95% confidence interval (CI) = 16.49-26.40, P < 0.001] and Hedges' g = 1.05 (95% CI = 0.86-1.24, P < 0.001). The difference was robust, remaining significant after removing outliers and studies with high risk of bias. Individuals with SUDs demonstrated poorer emotion regulation on each subscale of the DERS, with the largest deficits in the Strategies and Impulse subscales. The ERQ analysis revealed greater use of expressive suppression in those with SUDs relative to controls (Hedges' g = 0.76, 95% CI = 0.25-1.28, P = 0.004).

CONCLUSIONS

People with substance use disorders appear to have greater difficulties in emotion regulation than people without substance use disorders.

No addiction transfer from preoperative food addiction to other addictive behaviors during the first year after bariatric surgery

OBJECTIVE

The aim of the present study was to investigate whether the remission of preoperative food addiction is associated with increases or new onset of other addictions within the first year following bariatric surgery.

METHODS

One hundred and twenty-five bariatric surgery patients were assessed before surgery (t1) and at 6 months (t2) and 1 year (t3) follow-ups. The assessments included the Yale Food Addiction Scale 2.0 (YFAS 2.0) and standardized questionnaires to measure symptoms of problematic alcohol use, gambling disorder, internet-use disorder, buying-shopping disorder, hypersexual disorder and exercise dependence.

RESULTS

Forty-nine (39.2%) patients were assigned to the food addiction (FA⁺ ) and 76 patients (60.8%) to the non-food addiction group (FA^- ) based on their preoperative YFAS scores. Overall, BMI and symptoms of food addiction decreased significantly from baseline to follow-ups. Preoperative food addiction status was not associated with postoperative increases or new onset of other addictions. Elevated symptoms of buying-shopping disorder, internet-use and hypersexual behaviour at baseline in the FA⁺ -group decreased over time and were comparable to the FA^- -group at follow-ups.

CONCLUSION

The 'addiction transfer' or 'cross addiction' hypothesis was not supportive for alcohol addiction, gambling addiction or other behaviours that may be addictive. Further studies are needed that investigate larger samples and longer observation periods, as well as other substance-use disorders.

Converging vulnerability factors for compulsive food and drug use

Highly palatable foods and substance of abuse have intersecting neurobiological, metabolic and behavioral effects relevant for understanding vulnerability to conditions related to food (e.g., obesity, binge eating disorder) and drug (e.g., substance use disorder) misuse. Here, we review data from animal models, clinical populations and epidemiological evidence in behavioral, genetic, pathophysiologic and therapeutic domains. Results suggest that consumption of highly palatable food and drugs of abuse both impact and conversely are regulated by metabolic hormones and metabolic status. Palatable foods high in fat and/or sugar can elicit adaptation in brain reward and withdrawal circuitry akin to substances of abuse. Intake of or withdrawal from palatable food can impact behavioral sensitivity to drugs of abuse and vice versa. A robust literature suggests common substrates and roles for negative reinforcement, negative affect, negative urgency, and impulse control deficits, with both highly palatable foods and substances of abuse. Candidate genetic risk loci shared by obesity and alcohol use disorders have been identified in molecules classically associated with both metabolic and motivational functions. Finally, certain drugs may have overlapping therapeutic potential to treat obesity, diabetes, binge-related eating disorders and substance use disorders. Taken together, data are consistent with the hypotheses that compulsive food and substance use share overlapping, interacting substrates at neurobiological and metabolic levels and that motivated behavior associated with feeding or substance use might constitute vulnerability factors for one another. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Psychopathology, disordered eating, and impulsivity in patients seeking bariatric surgery

BACKGROUND

Most patients who undergo bariatric surgery experience significant weight loss and improvements in obesity-related co-morbidities in the first 6-18 months after surgery. However, 20%-30% of patients experience suboptimal weight loss or significant weight regain within the first few postoperative years. Psychosocial functioning may contribute to suboptimal weight loss and/or postoperative psychosocial distress.

OBJECTIVE

Assess psychosocial functioning, eating behavior, and impulsivity in patients seeking bariatric surgery.

SETTING

Two university hospitals.

METHODS

Validated interviews and questionnaires. Impulsivity assessed via computer program.

RESULTS

The present study included a larger (n = 300) and more racially diverse (70% non-White) sample than previous studies of these relationships. Forty-eight percent of participants had a current psychiatric diagnosis and 78% had at least 1 lifetime diagnosis. Anxiety disorders were the most common current diagnosis (25%); major depressive disorder was the most common lifetime diagnosis (44%). Approximately 6% of participants had a current alcohol or substance use disorder; 7% had a positive drug screen before surgery. A current psychiatric diagnosis was associated with greater symptoms of food addiction and night eating. Current diagnosis of alcohol use disorder or a lifetime diagnosis of anxiety disorders was associated with higher delay discounting.

CONCLUSION

The study identified high rates of psychopathology and related symptoms among a large, diverse sample of bariatric surgery candidates. Psychopathology was associated with symptoms of disordered eating and higher rates of delay discounting, suggesting impulse control issues.

A review of the psychosocial aspects of clinically severe obesity and bariatric surgery

For the past 2 decades, clinically severe obesity (operationalized as a body mass index ≥40 kg/m2) has increased at a more pronounced rate that less severe obesity. As a result, the surgical treatment of obesity (bariatric surgery) has become a more widely accepted, yet still underutilized, treatment for persons with severe obesity and significant weight-related health problems. Psychologists play a central role on the multidisciplinary team involved in the preoperative assessment and postoperative management of patients. They also have played a central role in clinical research which has enhanced understanding of the psychosocial and behavioral factors that contribute to the development of severe obesity as well as how those factors and others contribute to postoperative outcomes. This article, written specifically for psychologists and other mental health professionals who currently work with these patients or are considering the opportunity to do so in the future, reviews these contributions over the past 20 years. The article highlights how this work has become a fundamental part of international clinical care guidelines, which primarily focus on preoperative psychosocial screening. The article also outlines avenues for future research in the field, with a specific focus on the need for additional behavioral and psychosocial interventions to promote lifelong success after bariatric surgery. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Marijuana and Bariatric Surgery

PURPOSE OF REVIEW

Marijuana use presents a unique challenge to bariatric surgery programs. We review the recent evidence examining marijuana use on outcomes following bariatric surgery.

RECENT FINDINGS

Recent studies have not demonstrated an increased risk of short-term surgical complications or differences in up to 2-year weight loss following surgery among marijuana users. However, studies have demonstrated increased risks in two areas: pain management and problematic eating behaviors. Additionally, preoperative marijuana use has been linked to increased postoperative marijuana use which may undermine weight loss and increase risk for weight regain. There are still many unanswered questions regarding marijuana use and bariatric surgery, and the limited literature base has produced mixed results when considering marijuana as a contraindication for bariatric surgery. Programs must take into consideration the laws of their state, individual patterns of use, and route of administration when considering whether marijuana is a contraindication for surgery.

Characteristics of Patients Reporting Presumed Problematic Drinking Behavior After Gastric Bypass: Exploring Long-Term Data From the BAROBS Study

OBJECTIVE

To explore patients' long-term experiences with drinking alcohol after Roux-n-Y gastric bypass (RYGB) for conceptualizing what may indicate problematic drinking behavior after bariatric surgery.

STUDY DESIGN

Three-center, observational study.

PATIENTS

546 adult patients undergoing RYGB in the period 2003-2009 in Norway.

MAIN OUTCOME MEASURES

Self-reported data on drinking behavior and experiences related to alcohol collected 10-15 years after surgery.

RESULTS

Out of the 959 patients undergoing RYGB in the period, 29 were diseased and 546 participated in this follow-up study (58.7%). Focusing on suspicious changes in drinking behavior, 8.8% reported drinking more, 11.5% consumed alcohol at least twice a week, and 10.6% consumed at a minimum of 6 units of alcohol at a frequency of at least once monthly. The nature of hangovers had changed for about a third of the patients, with 21.6% reporting these to feel weaker or absent. Repeated alcoholic blackouts were reported by 11.9%. A subgroup of the patients were categorized as displaying presumed problematic drinking behavior(PPDB). Among the PPDB-men there was a significant association to having had a fall last year (6 (100.0%) PPDB-patients vs. 30 (29.7%) non-PPDB, p<.001). Among the PPDB-women, there was a significant association to having had alcohol problems prior to surgery (7 (70.0%) PPDB-patients vs. 67 (17.7%) non-PPDB, p<.001). Less significant associations to PPDB reported for explorative purposes were lack of patient education (men) (16 (26.2%) PPDB-patients vs. 8 (61.5%) non-PPDB, p=.014); more than 3 months persistent musculoskeletal pain (women) (45 (15.3%) PPDB-patients vs. 29 (24.6%) non-PPDB, p=.026); subjective problems with memory (women) (58 (20.7%) PPDB-patients vs. 10 (9.1%) non-PPDB, p=.006); and, receiving professional help for mental problems last 12 months (women) (29 (22.7%) PPDB-patients vs. 45 (14.7%) non-PPDB, p=.043).

CONCLUSION

A subset of patients display drinking behaviors that may be consistent with postsurgical alcohol problems. Screening instruments like AUDIT may not be sufficiently specific to capture several risk behaviors occurring after bariatric surgery.

Predictors of Alcohol Use after Bariatric Surgery

Patients undergoing bariatric surgery are at risk for devloping an alcohol use disorder (AUD). The purpose of this study was to investigate pre-surgical psychosocial risk factors for post-surgical alcohol consumption and hazardous drinking. Participants (N = 567) who underwent bariatric surgery between 2014 and 2017 reported their post-surgical alcohol use. Information was collected from the pre-surgical evaluation including history of alcohol use, psychiatric symptoms, and maladaptive eating behaviors (i.e., binge eating, purging, and emotional eating). Younger age and pre-surgical alcohol use predicted post-surgical alcohol use and hazardous drinking. In addition, higher levels of depressive symptoms and maladaptive eating patterns predicted post-surgical binge drinking. Clinicians conducting pre-surgical psychosocial evaluations should be aware of the multiple risk factors related to post-surgical problematic alcohol use. Future research should evaluate whether preventive interventions for high-risk patients decrease risk for post-surgical alcohol misuse.

Use of Opioid Analgesics Before and After Gastric Bypass Surgery in Sweden: a Population-Based Study

BACKGROUND

Little is known regarding the use of opioid analgesics among patients who have undergone bariatric surgery. The Roux-en-Y gastric bypass (RYGB) procedure has been shown to significantly increase the rate of absorption of and exposure to morphine, raising concerns regarding the potentially increased risk of side-effects and the development of substance-use disorder.

OBJECTIVES

The aim of this study was to describe the pattern of opioid use over time following RYGB and to see if the pattern differs between patients with a high opioid consumption (HOC) prior to surgery and those with a low consumption (LOC).

SETTING

University Hospital of Örebro, Sweden.

METHODS

The study was a descriptive retrospective population-based cohort study where two registers with complete coverage were cross-matched.

RESULTS

The study population comprised 35,612 persons (1628 HOC, and 33,984 LOC). After surgery, the number of HOC patients increased to 2218. Mean daily opioid consumption in the total population and the LOC group increased after surgery (p < .0005). In the HOC group, there was no difference between mean daily consumption before and after surgery.

CONCLUSION

In this nationwide study, we have showed that there is an increase in consumption of opioid analgesics after gastric bypass surgery in Sweden. The increase in the number of individuals with high opioid consumption in the total population was mainly due to an increase in the group of patients with a low consumption prior to surgery.

Problematic Alcohol Use and Associated Characteristics Following Bariatric Surgery

PURPOSE

Evidence suggests that a significant minority of individuals who undergo Roux-en-Y gastric bypass (RYGB) experience problematic alcohol and substance use following surgery. However, little research has examined characteristics, drinking patterns, and possible risk factors within this population. To provide descriptive information of a sample of adults with self-identified alcohol use problems following bariatric surgery, this study examined (1) alcohol and substance use symptoms using standardized assessments, (2) current and past psychiatric comorbidity, (3) subjective changes in alcohol sensitivity following surgery, and (4) specific patterns of alcohol use prior to and following bariatric surgery.

MATERIALS AND METHODS

Adult participants (N = 26) completed a series of structured diagnostic interviews and self-report assessments (e.g., Alcohol Use Disorders Identification Test [AUDIT], Michigan Alcohol Screening Test [MAST], Drug Abuse Screening Test [DAST]) by telephone 1 to 4 years following a RYGB or sleeve gastrectomy.

RESULTS

All participants met objective criteria for current problematic alcohol use based on AUDIT and MAST cutoff scores, reported increased subjective sensitivity to alcohol following surgery, and evidenced significant current and past psychiatric comorbidities, most notably previous major depression (45.5%). Approximately one third of participants evidenced new-onset Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) alcohol use or dependence following surgery. Preoperative drinking frequencies and quantities were similar to those reported during the period of the heaviest postoperative alcohol use.

CONCLUSIONS

Findings have implications for pre- and postoperative prevention and intervention efforts. Additional research is needed to further elucidate risk factors for problematic alcohol use following bariatric surgery.

Changes in Alcohol Use after Metabolic and Bariatric Surgery: Predictors and Mechanisms

PURPOSE OF REVIEW

This review synthesized the literature on predictors and mechanisms of post-bariatric alcohol problems, in order to guide future research on prevention and treatment targets.

RECENT FINDINGS

Consistent evidence suggests an elevated risk of developing problems with alcohol following bariatric surgery. While there is a paucity of empirical data on predictors of problematic alcohol use after bariatric surgery, being male, a younger age, smoking, regular alcohol consumption, pre-surgical alcohol use disorder, and a lower sense of belonging have predicted alcohol misuse post-operatively. This review synthesizes potential mechanisms including specific bariatric surgical procedures, peptides and reinforcement/reward pathways, pharmacokinetics, and genetic influences. Finally, potential misperceptions regarding mechanisms are explored. Certain bariatric procedures elevate the risk of alcohol misuse post-operatively. Future research should serve to elucidate the complexities of reward signaling, genetically mediated mechanisms, and pharmacokinetics in relation to alcohol use across gender and developmental period by surgery type.

Exploring pre-surgery and post-surgery substance use disorder and alcohol use disorder in bariatric surgery: a qualitative scoping review

INTRODUCTION

Bariatric surgery (BS) produces superior weight loss compared to non-surgical interventions. However, studies suggest bariatric patients who have undergone gastric-bypass surgery have an increased risk of developing new onset substance use disorder (SUD) or suffer negative outcomes after surgery. As such, many bariatric programs consider alcohol/ illicit drug misuse a contraindication to BS. The purpose of this systematic review was to investigate weight loss outcomes, post-surgery substance use patterns and other morbidity/mortality in BS patients with a history of substance use/SUD.

METHODS

Studies were identified by searching Ovid Medline(R), Embase, and PsychInfo. We included all study types investigating humans of any age/sex who had undergone any BS procedure with data regarding substance use before and/or after surgery. Outcome measures included metabolic outcomes and psychiatric outcomes after bariatric surgery in patients reporting substance use prior to bariatric surgery and substance use patterns after bariatric surgery.

RESULTS

Fifty-eight studies were included in the review. Studies reporting weight loss after BS did not demonstrate an association between substance use and negative weight loss outcomes. Several studies reported a significant portion of participants having new onset or increased substance use after BS. Factors associated with new onset or increased substance use/SUD after BS included the type of surgery, a history of SUD, a family history of SUD, coping skills/life stressors, age, male sex and alcohol sensitization after surgery.

CONCLUSION

Substance use history does not appear to influence weight loss after BS, however it may contribute to increased substance use after BS. Clinicians should ensure valid screening tools when assessing BS candidates for substance use history and ensure long term follow-up care post-operatively.

Effect of vertical sleeve gastrectomy on alcohol consumption and preferences in dietary obese rats and mice: A plausible role for altered ghrelin signaling

Vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) are the most common surgical options for the treatment of obesity and metabolic disorder. Whereas RYGB may result in greater and more durable weight loss, recent clinical and pre-clinical studies in rats have raised concerns that RYGB surgery may increase risk for alcohol use disorder (AUD). In contrast, recent clinical reports suggest a lesser risk for AUD following VSG, although no preclinical studies have been done to confirm that. Therefore, the present study sought to determine the effects of VSG on ethanol intake and preferences in rodent models using protocols similar to those previously used in animal studies for RYGB. Male Sprague Dawley rats and male C57B6 mice were made obese on a high fat diet (60%kcal from fat) and received VSG or no surgery (controls). All animals then were given access to increasing concentrations of ethanol (2%, 4%, 6%, and 8%), presented for few days each. Compared to controls, VSG rats consumed significantly less of 2, 6 and 8% ethanol and showed significantly reduced preferences to 6 and 8% ethanol over water. VSG mice also displayed reduced intake and preference for 6 and 8% ethanol solutions. After a two-week period of forced abstinence, 8% ethanol was reintroduced and the VSG rats and mice continued to exhibit reduced consumption and less preference for ethanol. Regarding the underlying mechanism, we hypothesized that the removal of the ghrelin producing part of the stomach in the VSG surgery is a possible contributor to the observed reduced ethanol preference. To test for functional changes at the ghrelin receptors, the VSG and control rats were given IP injections of acyl-ghrelin (2.5nmol and 5nmol) prior to ethanol access. Neither concentration of ghrelin resulted in a significant increase in 8% ethanol consumption of VSG or control subjects. Next, the rats were given IP injections of the ghrelin receptor antagonist, JMV (2.5mg/kg body weight). This dose induced a significant reduction in 8% ethanol consumption in the VSG group, but no effect on ethanol intake in the controls. While ghrelin injection was uninformative, increased sensitivity to subthreshold doses of the ghrelin receptor antagonist may indicate reduced ghrelin signaling following VSG. Overall, these findings suggest that bariatric patients with increased susceptibility to AUD may benefit from receiving VSG instead of RYGB surgery, and that changes in ghrelin signaling, at least in part, may play a role in the differential AUD risks between the two most commonly performed bariatric surgical procedures.

Obesity and addiction: can a complication of surgery help us understand the connection?

Obesity is a multifactorial, chronic disease that has proven difficult to treat. An increased understanding of aetiological mechanisms is critical to the development of more effective obesity prevention and treatment strategies. A growing body of empirical evidence has demonstrated parallels between obesity, overeating and substance abuse, including shared behavioural, psychological and neurophysiological factors implicated in the excessive intake of both food and substances of abuse. Several different lines of research have recently emerged that hold the potential to shed light on the connection between obesity, food reward and addiction, with studies examining changes in alcohol use/misuse after weight loss surgery providing a particularly interesting perspective on these interrelationships. However, these lines of investigation have proceeded in relative isolation, and relevant research findings have yet to be integrated in a synthesized, comprehensive manner. To provide an opportunity to achieve such a synthesis, a scientific symposium was convened at the Radcliffe Institute in Cambridge, Massachusetts. Invited participants were researchers working in diverse domains related to the intersection between obesity and addiction. Extensive discussion was generated suggesting novel research directions. In this article, we summarize and synthesize the symposium participants' ongoing research in this area, incorporating additional relevant research holding potential clues regarding the connections between obesity, weight loss surgery and addiction.

Substance use after bariatric surgery: A review

BACKGROUND

Prevalence of obesity has increased dramatically. Obese individuals may undergo bariatric surgery to lose excessive body fat and mitigate obesity-related comorbidities. However, bariatric patients are particularly vulnerable to substance use problems. We conducted a review to examine the prevalence change and factors associated with substance use and determine the association between substance use and health status after weight loss among bariatric patients.

METHODS

We searched peer-reviewed articles published between January 1990 and January 2015 in several databases (PubMed, PsycINFO, Cochrane Library, Google Scholar) using different keywords combinations. Studies that focused on pre-surgery substance use only or without reported effect measurements were excluded.

RESULTS

Overall, 40 studies were included in the review. Preoperative history of substance use was a reliable correlate of postoperative substance use. The prevalence of postoperative alcohol use was higher among patients with preoperative history of alcohol use than those without. Postoperative prevalence of alcohol use ranged from 7.6% to 11.8%. No significant prevalence change in cigarette smoking from pre-to postoperative period was observed. Time effect was not observed on smoking or drug use prevalence, while an increase in alcohol consumption was inconsistent across studies. The proportion of new-onset substance users among bariatric patients after surgery ranged from 34.3% to 89.5%.

CONCLUSION

Substance use is associated with poor health among bariatric patients. Preoperative assessment and postoperative follow-up should include interventions to reduce relapse among users and prevent substance use initiation.

Alcohol and Drug Use Among Postoperative Bariatric Patients: A Systematic Review of the Emerging Research and Its Implications

BACKGROUND

Emerging research suggests that some bariatric surgery patients are at a heightened risk for developing substance use problems, especially alcohol use problems.

METHODS

An exhaustive literature review was conducted in January 2015 to investigate all articles published that included data on postoperative alcohol use, alcohol use disorders, and illicit drug use among bariatric surgery patients.

RESULTS

Twenty-three studies reported on alcohol and/or substance use among bariatric patients. Six studies longitudinally assessed alcohol use behaviors; 3 of these studies found an increase in alcohol use following surgery. Six studies were cross-sectional, and 2 studies assessed medical records. Five studies investigated the prevalence of admissions to substance abuse treatment, and 3 studies combined alcohol and drug use data in a single index. Six studies reported on illicit drug use and reported low-postoperative use. The studies' samples were primarily non-Hispanic white females in their upper 40s, and only 11 of the 23 studies utilized validated assessment instruments.

CONCLUSIONS

Studies employing longitudinal designs and large sample sizes indicate that bariatric patients who had the gastric bypass procedure are at an elevated risk for alcohol use problems postoperatively. Research also indicates that bariatric surgery patients might be overrepresented in substance abuse treatment facilities. Risk factors for problematic postoperative alcohol use include regular or problematic alcohol use presurgery, male gender, younger age, tobacco use, and symptoms of attention deficient and hyperactivity disorder. As a whole, however, studies indicate bariatric surgery patients demonstrate a low prevalence of problematic alcohol use, and studies about gastric bypass patients are not entirely conclusive. Prospective, longitudinal studies are needed, utilizing standardized and validated alcohol assessment instruments that follow postoperative bariatric patients well beyond 2 years, and account for types of bariatric procedure. Finally, study samples with greater racial/ethnic diversity and wider age ranges are needed.

Increased intravenous morphine self-administration following Roux-en-Y gastric bypass in dietary obese rats

Roux-en-Y gastric bypass (RYGB) surgery is a commonly performed and very effective method to achieve significant, long-term weight loss. Opioid analgesics are primarily used to manage postoperative pain as fewer alternative medication options are available for bariatric surgery patients than for the general population. Recent clinical studies support a greater risk for substance use following bariatric surgery, including an increased use of opioid medications. The present study is the first to study morphine self-administration in a rat model of RYGB. High fat diet-induced obese (HFD-DIO) rats underwent RYGB (n=14) or sham-surgery with ad libitum HFD (SHAM, n=14) or a restricted amount that resulted in weight matched to the RYGB cohort (SHAM-WM, n=8). An additional normal-diet (ND, n=7), intact (no surgery) group of rats was included. Two months after the surgeries, rats were fitted with jugular catheters and trained on a fixed ratio-2 lick task to obtain morphine intravenously. Both morphine-seeking (number of licks on an empty spout to obtain morphine infusion) and consumption (number of infusion) were significantly greater in RYGB than any control group beginning on day 3 and reached a two-fold increase over a period of two weeks. These findings demonstrate that RYGB increases motivation for taking morphine and that this effect is independent of weight loss. Further research is warranted to reveal the underlying mechanisms and to determine whether increased morphine use represents a risk for opioid addiction following RYGB. Identifying risk factors preoperatively could help with personalized postoperative care to prevent opioid abuse and addiction.