Psychopathology, Disordered Eating, and Impulsivity as Predictors of Outcomes of Bariatric Surgery
Condition: Obesity
MeSH terms: Impulsive Behavior
Study type: Observational

Summary: 
      This study will evaluate the relationship between psychopathology, disordered eating, and
      impulsivity (measured by clinical interview, self-report measures, and objective testing) on
      changes in weight and psychosocial status in the first two years after bariatric surgery.
      Participants will be 300 adults who plan to undergo bariatric surgery. Participants will
      complete four assessments over a two-year period, one at baseline (before surgery) and 6, 12,
      and 24 months after surgery. Each assessment will include computer tasks, surveys, clinical
      interview, urine test, waist circumference and height/weight measurement. The investigators
      will track how psychopathology, disordered eating, and impulsivity are related to changes in
      weight and psychosocial status following bariatric surgery.
    

Detailed description: 
      Psychosocial Status and Psychopathology in Candidates for Bariatric Surgery:

      Extreme obesity is associated with a signiﬁcant psychosocial burden, including impairments in
      quality of life, body image, sexual behavior and other areas of psychosocial functioning.
      While this distress is believed to contribute to the decision to have bariatric surgery, its
      impact on postoperative outcomes is less clear. At present, little is known about the
      physiological and behavioral contributions to success or failure of bariatric surgery.
      Regardless, weight regain after bariatric surgery is frequently attributed to preoperative
      psychosocial and behavioral factors. More speciﬁcally, there has been a great deal of
      interest in the presence of formal psychopathology in bariatric surgery patients and its
      potential contribution to postoperative outcomes. At least six studies have described rates
      of psychopathology in candidates for bariatric surgery using structured diagnostic
      instruments. Lifetime rates of any psychiatric diagnoses ranged from 36.8%-72.6%, higher than
      those reported in most studies of the general population. Mood disorders were the most
      frequent diagnoses, seen in 22.0%-54.8% of patients. Substance use disorders (SUDs) were
      found in up to 35.7% of patients and alcohol abuse or dependence in up to 33.2%. Binge eating
      disorder (BED), deﬁned as eating an unusually large amount of food within a short period of
      time coupled with a loss of control over eating, has been diagnosed in 4.6% to 27.1% of
      patients. Current diagnoses (as compared with lifetime) were less common, reported in
      20.9%-55.5% of candidates for surgery. Mood disorders were diagnosed in up to 31.5%. BED
      ranged from 3.4%-41.9%. Current substance use was seen in less than 2% of patients. (Note.
      The lower percentages of those with current psychopathology, as opposed to lifetime
      psychopathology, are expected.) While studies of the psychosocial characteristics of
      bariatric surgery candidates have been informative, they are not without limitations. Many
      studies have suffered from methodological concerns, including small sample sizes or lack of
      an appropriate comparison group. Further, establishing psychiatric diagnoses prior to
      bariatric surgery is challenging. Perioperative guidelines suggest that patients undergo an
      evaluation with a mental health professional prior to surgery and most third party payers
      require these evaluations. However, most programs do not use structured clinical interviews
      to establish diagnoses for clinical purposes. Several studies have suggested that candidates
      for bariatric surgery engage in impression management prior to surgery, in which they
      minimize reports of psychopathology to present themselves to the bariatric team in the most
      favorable light. To address this issue, assessment of psychiatric symptoms for research
      purposes is recommended to occur independently from the required clinical evaluation, as the
      investigators will do in the proposed study. Nevertheless, studies focusing on the
      relationship between speciﬁc diagnoses and postoperative outcomes may fail to account for
      other psychological constructs that may be shared across diagnoses. Mood disorders, BED, and
      SUDs all share the common psychological construct of impulsivity, considered an important
      aspect of executive functioning. A lack of impulse control may contribute to the excessive
      weight gain seen in extreme obesity and may impact the results of bariatric surgery.

      Disinhibition and Impulsivity among Persons with Extreme Obesity; Studies have suggested that
      individuals with obesity, and in particular those with extreme obesity presenting for
      bariatric surgery, show some deﬁcits in executive functioning. For example, candidates for
      bariatric surgery have shown deﬁcits in working memory, mental ﬂexibility, motor speed and
      complex attention.These deﬁcits could impact comprehension and retention of information
      presented to patients during the preoperative consultation process and, thus, negatively
      impact the ability to adhere to the dietary and behavioral changes required for an optimal
      postoperative outcome. At the same time, metabolic dysregulation, such as insulin resistance
      or hyperglycemeia seen in type 2 diabetes, also is associated with cognitive deﬁcits,
      suggesting a potential physiological mechanism for the relationship. Dietary disinhibition,
      deﬁned as a loss of control over eating, plays a central role in the overconsumption of food
      and, subsequently, the development of obesity. Disinhibition is similar to impulsivity, the
      term more commonly used in the substance use and smoking cessation literatures. Impulsivity
      is a multi-faceted construct and refers to the absence of the ability to inhibit an automatic
      behavior (otherwise known as response inhibition) and the tendency to discount future
      consequences in favor of more immediate outcomes (known as delay discounting). Similar to the
      role of disinhibition in obesity, impulsivity contributes to the development of and relapse
      with SUDs. Indeed, response inhibition and delay discounting are associated with both SUDs
      and obesity. Both also predict response to treatment for both SUDs and obesity. Chronic
      overeating and binge eating share several neurobiological and behavioral similarities with
      SUDs. In this regard, both may be viewed as behavioral disorders, in which intake (of food,
      alcohol, and/or drugs) escalates to a rate that is unhealthy and maladaptive. Nevertheless,
      the speciﬁc nature of the relationship between binge eating and substance use remains to be
      fully elucidated. There are similarities between binge eating and addictive disorders,
      including craving for the desired substance (drug or highly palatable food), a sense of loss
      of control when using, repeated attempts to control use despite clear adverse consequences,
      and the dedication of much time in obtaining and using the substance. Thus, the disinhibition
      observed with obesity and binge eating, the impulsivity seen with substance use disorders,
      and the emotional dysregulation associated with mood disorders all likely share commonalities
      that may both contribute to the development of extreme obesity and also may be associated
      with weight loss and changes in psychosocial status after bariatric surgery.

      Psychosocial Status and Psychopathology after Bariatric Surgery:

      In general, individuals who undergo bariatric surgery report dramatic improvements in
      psychosocial status and functioning postoperatively. The vast majority of patients report
      signiﬁcant reductions in symptoms of depression and anxiety in the ﬁrst postoperative year.
      They also report signiﬁcant improvements in health and weight-related quality of life.
      Patients also report improvements in body image, sexual functioning, and relationship
      satisfaction. The relationship between preoperative psychopathology and postoperative
      outcomes is less robust. Livhits and colleagues reviewed this literature and concluded that
      the preoperative factors of BMI, BED, and the presence of personality disorders provided the
      strongest negative associations with postoperative weight loss. At least two studies have
      suggested that preoperative psychopathology, particularly mood and anxiety disorders, is
      associated with smaller weight postoperative weight losses. The relationship between BED and
      postoperative weight loss is unclear; some studies have found a relationship between
      preoperative BED and postoperative weight loss while others have not. Additionally, two
      studies have suggested that a history of substance abuse is associated with larger weight
      losses following bariatric surgery. The interpretation of this counterintuitive ﬁnding is
      that the self-regulation skills that help patients maintain their sobriety also help patients
      adhere to the demands of the recommended postoperative diet.

      Disinhibition and Impulsivity following Bariatric Surgery Encouragingly, studies have shown
      that there are improvements in executive functioning in persons with extreme obesity in the
      ﬁrst two years after bariatric surgery. Postoperatively, patients typically report decreases
      in disinhibition and hunger, as well as increases in cognitive restraint. The physical
      aspects of bariatric surgery typically prevent individuals from eating the objectively large
      amount of food necessary to meet the diagnostic criteria of BED. However, many individuals
      continue to report the feeling of loss of control over their eating.The self-reported
      inability to control these impulses postoperatively is associated with smaller weight losses
      and greater emotional distress in the ﬁrst few postoperative years. There is additional
      evidence that patients have difﬁculty with impulse control after surgery. A number of studies
      have suggested that there is an increased risk of substance abuse following bariatric
      surgery. King and colleagues, in their seminal investigation, found an increased rate of
      alcohol use disorder in the second postoperative year as compared to the year prior to
      surgery or in the ﬁrst postoperative year. Other recent studies also have found increases in
      alcohol or composite substance abuse (drug, alcohol, or cigarettes) in the ﬁrst two years
      after bariatric surgery. Postoperative substance use has been associated with smaller
      postoperative weight losses, postoperative nocturnal eating, and subjective hunger. Patients
      at greatest risk for new onset SUDs were more likely to report problems with high sugar/low
      fat food before surgery, further suggesting the role of impulsivity in eating behavior and
      substance use before and after surgery. This increase in substance abuse after surgery has
      been described as addiction transfer and characterized as a modern example of symptom
      substitution in which abuse of one substance (food) is replaced by another (alcohol or drugs)
      when patients are unable to consume large amounts of food after surgery. A potential
      contributor to addiction transfer may be emotional dysregulation. In general, symptoms of
      depression typically improve within the ﬁrst six months of bariatric surgery as patients are
      in the period of most rapid weight loss. Within the ﬁrst two postoperative years, the use of
      anti-depressant medications also decreases; however, a substantial minority of patients
      report using these medications two years after surgery. As most patients begin to regain
      weight postoperatively, they also experience an erosion of the improvements in depressive
      symptoms and quality of life. In addition, a higher-than-expected number of postoperative
      suicides have been documented. A secondary aim of the proposed study will investigate the
      relationship between changes in weight during the ﬁrst two postoperative years and changes in
      psychosocial status.

      The proposed observational study will evaluate the relationship between measures of
      psychopathology, disordered eating, and impulsivity, (each assessed preoperatively and in the
      early postoperative period) and changes in weight and psychosocial status in the first two
      years after bariatric surgery. All participants will complete assessments at baseline (before
      surgery) and at 6, 12, and 24 months follow-up. Secondary aims will examine psychopathology,
      disordered eating, impulsivity, as well as weight loss, in relation to changes in eating
      behavior, physical activity, psychosocial status, and substance use in the first two years
      after bariatric surgery. The study has one specific aim and two secondary aims.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Participants will be recruited from the Bariatric Surgery Programs at the Hospital of the
        University of Pennsylvania and Presbyterian Medical Center, all part of Penn Medicine. The
        investigators will enroll participants until a total of 300 adults have completed baseline
        visits. Based on the investigator's previous studies of bariatric surgery patients, the
        investigators expect that approximately 80% of participants will be women and 20% of
        participants will be ethnic minorities.