Individuals who undergo bariatric surgery, particularly Roux-en-Y gastric bypass (RYGP), have a significantly increased risk of developing a substance use disorder (SUD), in particular alcohol use disorder (AUD), new research shows.

The increased risk is not observed until after the first postoperative year, and risk factors include a preoperative history of substance use, especially alcohol; younger age; male sex; and smoking, said lead investigator Cameron Risma, MD, Pine Rest Christian Mental Health Services, Grand Rapids, Michigan.

In addition, people who chronically used opiates before the surgery tend to continue chronic use after surgery, Risma said.

“We got the idea to study substance use disorders after bariatric surgery because we see a lot of it in our detox program at Pine Rest. It’s common. People come in years after surgery, and they never realized that this was an issue,” he told Medscape Medical News.

The findings were presented here at the American Academy of Addiction Psychiatry (AAAP) 29th Annual Meeting.

Fivefold Increased Risk

For the study, investigators conducted a PsychINFO and Web of Science search for articles published from 1996 to 2018 on the relationship between gastric bypass surgery and SUD.

They found that a 2013 prospective study that followed more than 4000 obese patients showed those who underwent bariatric surgery were nearly five times more likely to receive a diagnosis of alcohol abuse during a follow-up period of 8 to 22 years.

Another 2012 prospective study that followed almost 2500 bariatric surgery patients showed a significantly increased prevalence of symptoms of AUD during the second postoperative year compared to the first postoperative year (9.6% vs 7.3%).  There was no difference between the year immediately before (7.6%) or after (7.3%) the surgery.

The same study identified preoperative variables independently associated with increased risk of developing an AUD after bariatric surgery.  These included previous AUD, regular alcohol use (defined as >2 drinks per week), smoking, recreational drug use, male sex, RYGB, younger age, and low sense of belonging.

Two systematic reviews showed that approximately 8% of patients were chronic opiate users at the time of surgery, and that most continued using opioids in the year following surgery.

However, use of other substances after bariatric surgery remained unchanged.

Three hypotheses have been proposed to account for the link between bariatric surgery and addiction, Risma said.

“No one really knows exactly why, but one hypothesis is this idea of addiction transfer.  Binge eating can lead to obesity, so you get addicted to food. But after you have surgery, you can’t binge on food anymore so you turn to something else which happens to be a substance, to replace food. The idea is that you are using a substance to cope with a negative emotional state,” Risma said.

The next hypothesis is based on neurobiological mechanisms, supported by evidence from PET scans, which have shown similarly reduced D2 receptors in both pathologic obesity and addiction.

“It is possible that reduced striatal D2 receptors predispose an individual to search for strong dopaminergic reinforcement as a compensatory mechanism for dopamine hyposensitivity. This dopamine-based hypothesis is supported by neuroimaging studies showing that a rapid dopamine release is produced both by binge eating and IV alcohol infusion,” the authors write.

The third hypothesis is based on pharmacokinetic changes after RYGB, leading to a hypersensitivity to alcohol’s reinforcing effects.

“This is really interesting,” Risma said. “After Roux-en-Y gastric bypass, you get a hypersensitivity to alcohol’s effects, where even a small amount of alcohol can achieve very high blood alcohol concentrations.

“One drink can put you over the legal limit in less than 15 minutes, so it reaches a higher blood alcohol content and it takes longer for the alcohol to get out of your system. Some people report that even after a few sips they can feel a buzz. They go back to drinking the same amount, they get more drunk, and they can become addicted that way,” he said.

These changes are only observed in RYGB, and no other bariatric surgeries such as gastric banding or sleeve gastrectomy, Risma said.

“The results of our survey show that it’s primarily alcohol that becomes the substance of abuse,” he added. “But clinically, I’ll tell you, we see a lot of opiate use in our detox unit. This is something we would to like to investigate going forward, because we are seeing so much of it. People who have surgery have chronic pain, they can’t get off their opioids, and they come to us addicted and needing withdrawal and treatment afterwards.

“We would like to work with local bariatric surgical centers and ask how they are identifying people based on the risk factors we found in our survey, and then once they are identified, ask how they are treating them. Are you offering them classes, are you following up with them more often? We think that’s an area where we can make a clinical impact.”

A Growing Problem

Commenting on the findings for Medscape Medical News, Cornel N. Stanciu, MD, assistant professor of psychiatry, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire, said the number of individuals undergoing bariatric weight loss procedures is expected to grow by 6% to 8% annually in the coming years.

“Positive outcomes can be quite striking. However, there are certain aspects which could worsen or emerge. With both obesity and addictions being stigmatized and overlooked as disorders of poor self-control, with perhaps common genetic, behavioral, social, neurobiological and pharmacokinetic factors, one emerging issue noted has been the association of bariatric surgery with development of postoperative addictions,” Stanciu said.

As with other surgeries, the biggest focus has been on limiting opioid use to prevent addictive tendencies, but here the biggest association seems to be with the development of risky alcohol use, he added.

“Some studies report this rate to be as high as 21% when the procedure is done via the RYGB method, and 11% when banding is done,” Stanciu said.

The finding of a delay in developing alcohol abuse patterns a year after surgery has significant implications. Historically, the most rigorous follow-up and aftercare occur immediately after the procedure and tapers off throughout the coming years.

“In an era that is shifting towards the ambulatory setting, providing prolonged aftercare and monitoring may present challenges,” he added.

Identifying factors that predispose individuals to alcohol abuse after their bypass should prompt implementation of additional safety nets, Stanciu said.

“Here, they found [that patients with] a history of alcohol use, undergoing the RYGB type of procedure, young age, male gender, and smokers may be predisposed. It’s important to implement better screening focused on these risk factors, as well as a more robust pre- and post-surgical education and closer follow-up.

“Also, because alcohol problems may not appear for years after the procedure, it is critical for all clinicians involved in the care of bariatric surgery patients to proactively assess alcohol consumption and be able to intervene early,” he said.

However, he added, the frequency of RYGB is decreasing, he noted.

“Initially, RYGB was more popular than banding as it led to more drastic weight loss. However, newer approaches such as sleeve gastrectomy and endoscopic modalities are rapidly taking over. Whether these may have a greater association with alcohol and other addictive behaviors is a great unknown at this time,” Stanciu said.