Scott G. Engel, Ph.D. - US grants

DESCRIPTION (provided by applicant): Recent research findings show an accelerated rate of absorption and heightened sensitivity to alcohol following bariatric surgery. Additionally, several alcohol-related automobile accidents and deaths have been reported following bariatric surgery. This literature supports earlier media reports suggesting significant changes in frequency of alcohol use and rate of intoxication from drinking alcohol. The combination of anecdotal and empirical evidence has led to the development of an "addiction transfer" model. This theory suggests that in the absence of the ability to use large amounts of food as a coping strategy, post-bariatric surgery patients may exchange this behavior for an alternative maladaptive behavior such as alcohol misuse. These findings have highlighted the current lack of knowledge in the field related to the frequency of alcohol use, the associated mood precipitants and consequences, and level of impairment following bariatric surgery. In the current study we propose to examine the use of alcohol in two groups of patients: pre-bariatric surgery patients and patients three to five years post bariatric surgery. We propose to study these patients with both laboratory and naturalistic assessment strategies in an effort to maximize control of the environment (laboratory assessment) and to assure ecological validity of the findings (naturalistic assessment). We believe that the proposed study will provide insight regarding the use of alcohol before and after bariatric surgery as well as valuable pilot data for a large scale, prospective, longitudinal study of the use of alcohol in a group of bariatric surgery patients. PUBLIC HEALTH RELEVANCE: The proposed project is particularly important to the understanding of changes that occur in the frequency of use, impairment, and antecedent and consequent conditions of alcohol use before and after bariatric surgery. Employing both laboratory and field assessment, the current study will provide both tightly controlled and naturalistic findings, which will be highly informative and clinically relevant to bariatric surgery patients.

Abstract: Recently our research group published a paper in JAMA which showed that after Roux-en-Y gastric bypass surgery (RYGB), patients are at significantly increased risk for developing an alcohol use disorder. Several lines of research are consistent with this finding: 1) anecdotal information from RYGB patients suggests that they become intoxicated much more quickly, 2) there are numerous reports of automobile accidents that have resulted from RYGB patients driving while intoxicated after drinking a small amount of alcohol, and 3) the pharmacokinetics of alcohol change considerably after RYGB. The pharmacokinetic changes are of considerable interest to us as they likely lead to significant impairments and changes in reinforcement. These changes may serve as a potential causal mechanism for the subsequent development of an alcohol use disorder. In the current study we propose to investigate RYGB patients with a prospective, longitudinal design. We will examine cognitive and driving impairment after surgery as well as study the changes in reinforcement that may occur in RYGB patients. Finally, we aim to better characterize the changes that occur in the pharmacokinetics of alcohol following bariatric surgery and examine key variables which may play a role in the development in alcohol use disorders.

Abstract: Recent studies have clearly indicated that a significant proportion of bariatric surgery patients experience substantial weight regain and struggle with depression following their surgery. Understanding the mechanisms that contribute to these negative clinical outcomes is of considerable scientific and clinical importance. In the present study, we propose a model of predictors that we believe result in weight regain and depression. We will test the idea that in the moment, stress and negative affect predict loss of control eating, and that over time, loss of control eating predicts weight regain and depression in these patients. We will also investigate the influence of disinhibition on these relationships. Furthermore, we will use contemporary ecological momentary assessment and ambulatory assessment techniques to measure these variables and study their relationship to weight regain and depression in a prospective, longitudinal design. Finally, we will longitudinally examine weight regain and depression following bariatric surgery to clarify the temporal relationship between these variables.