Outcomes of bariatric surgery, while frequently impressive, are not universal and vary between patients and across surgical procedures. Between 20% and 30% of patients experience suboptimal weight loss or significant weight regain within the first few postoperative years. The reasons for this are not fully understood, but likely involve both physiologic processes, behavioral factors, and psychological characteristics. Evidence suggests that preoperative psychosocial status and functioning can contribute to suboptimal weight losses and/or postoperative psychosocial distress. Much of this work has focused on the presence of recognized psychiatric diagnoses and with particular emphasis on mood disorders as well as binge eating disorder. Several studies have suggested that the presence of preoperative psychopathology is associated with suboptimal weight losses, postoperative complications, and less positive psychosocial outcomes. Contemporary psychological theory suggests that it may be shared features across diagnoses, rather than a discrete diagnosis, that better characterizes psychopathology. Mood and substance use disorders as well as binge eating disorder, share common features of impulsivity, although clinicians and researchers often use complementary, yet different terms, such as emotional dysregulation or disinhibition (i.e., loss of control over eating, as applied to food intake), to describe the phenomenon. Impulse control is a central factor in eating behavior and extreme obesity. It also may contribute to the experience of suboptimal outcomes after bariatric surgery, including smaller than expected weight loss and psychosocial distress. This paper reviews the literature in these areas of research and articulates a direction for future studies of these complex relationships among persons with extreme obesity.