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psychological factors

Surgeons need to look at bariatric patients’ psychological factors

Psychological condition can be an important indicator of surgical success
Mental health professionals can help to identify patients who are mentally unsuitable for surgery
No consensus regarding the exclusion criteria for patients with mental issues
Tom Stevens

The psychological condition of a bariatric patient can be an important indicator of the success of his treatment, according to a psychiatric specialist.

Dr Tom Stevens, consultant general adult and liaison psychiatrist at South London and Maudsley NHS Trust, said that psychiatric professionals can help establish whether a patient is psychologically able to cope with the demands of bariatric surgery.

Stevens was presenting with Dr Lisa McClelland, consultant general adult psychiatrist at Devon Partnership NHS Trust.

Bingeing and bulimia

Stevens identified two main eating disorders that are associated with obesity: binge eating, and bulimia nervosa.

Binge eating is defined under the DSM4 as eating, within a discrete period of time, an amount of food that is definitely larger than most people would eat during a similar period of time and under similar circumstances, coupled with a sense of lack of control over eating during the episode. These episodes should occur, on average, at least twice a week for three months.

Bulimia nervosa has similar symptoms to binge eating disorder, with added inappropriate compensatory behaviour to prevent weight gain, like self-induced vomiting or laxatives.

Diagnosing binge eating, said Stevens, is difficult to define due to the clinician having to rely on the patient’s unreliable recall of their food intake. “We know from psychology that recall of information is context-specific,” he said. “One of the problems is that people are in the calm context of the clinic when they are getting access to their history of eating, which is undertaken in an emotive state.”

Adverse outcomes and risk

Stevens said that bariatric surgery can lead to adverse psychiatric outcomes.

Patients who don’t disclose their problems with bulimia before surgery can amplify their self-induced vomiting. Enduring binge eating, malnutrition, and resultant psychiatric relapses can all result from unrealistic expectations of surgery. Also, while overall most instruments that measure mood show an improvement over the first 18 months of surgery, there is still an increased risk of suicide within the group.

These outcomes are controversial, however, as the evidence supporting them is largely based on case reports, rather than studies.

Despite the severity of the risks, there is no consensus about the exclusion criteria for patients with mental issues. The American National Institutes of Health suggest that uncontrolled psychopathology is an exclusion criterion, while NICE does not offer any guidance.

In response, Stevens and McClelland, along with Samantha Scholtz, created a traffic-light system of psychological indications for bariatric surgery (see boxout). Patients with green indications are generally psychologically able to undergo bariatric surgery. Those with amber indications are usually able to make an informed choice, but are at risk. “It’s contingent on everybody to optimise their functioning before they have their operation,” said Stevens. 

Red indications, which Stevens described as “probably the most controversial”, mean that “in our opinion you shouldn’t be proceeding with surgery and the patient will probably need to be sent back to a mental health service before you proceed.”

Overcoming issues

Stevens said that there were some that psychologists and psychiatrists were working to overcome in the bariatric service. 

Despite being able to make recommendations based on a patient’s psychosocial history, psychiatrists cannot predict weight loss. “There’s a real question mark regarding our role, considering we’re not able to predict outcomes,” said Stevens.

Stevens also highlighted the risk that psychiatrists may block access to treatment and inadvertently discriminate against patients with mental health problems. The lack of an evidence base to rely on also presented issues for psychiatrists.

“So there’s this discourse,” said Stevens, “suggesting that if people turn up to all their appointments, that’s a sign they’re motivated enough – go ahead with surgery, as long as they meet the NICE criteria.”

NICE guidelines, said Stevens, are vague on the use of psychiatry and psychology in the treatment of obesity. However, mental health professionals can help to identify patients who, while fitting into the NICE criteria, are mentally unsuitable for surgery.

Psychological indications traffic light system


  • Appropriate motivation – health rather than mental health
  • Good understanding of procedure and outcomes
  • Appropriate expectations for weight loss etc
  • Regular balanced diet
  • Insight into eating and causes of weight gain.
  • Proven compliance


  • In cases of severe mental illness, mental state should be stable with no hospital admissions or act of deliberate self harm for previous 12 months
  • History of alcohol or substance misuse
  • History of eating disorder
  • Mild learning difficulties
  • Poor motivation
  • Unrealistic expectations
  • Binge eating disorder
  • Inadequate insight into eating behaviours
  • History of poor compliance


  • Unstable psychosis
  • Active substance misuse and alcohol dependence
  • Severe/moderate learning difficulties
  • Dementia
  • Severe personality disorder
  • Self-harm within last 12 months
  • Active bulimia nervosa
  • Current non-compliance with treatment

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