Obesity and SUDs may be approached with a variety of treatment options, as summarized in . Treatment studies, meta-analyses, and alternative treatments are discussed below, as are potential gaps in understanding for which research in these areas may lead to the development of novel and potentially more efficacious treatments.
Proposed Similarities and Differences Between Obesity, SUDs, and BED
Obesity has long been treated with prescriptions for reduced-caloric diets and increased energy expenditure, though the efficacy of those measures has not been consistently established (Polivy & Herman, 1999
; Urbszat, Herman, & Polivy, 2002
). Dieting often involves restricted ingestion of desired high-caloric foods, and unsuccessful dieting efforts may involve the resumption of excessive consumption or bingeing of the same foods. This pattern shares similarities with withdrawal and relapse behaviors in SUDs. Cycling between withdrawal and relapse may lead to compulsive eating through changes in neurocircuitry function underlying stress responsiveness. Animal studies have implicated specific brain neurochemicals (e.g., the neuropeptide corticotrophin-releasing factor) as linking stress responsiveness and the motivation to eat palatable foods, suggesting a pathway for the induction of compulsive eating and novel targets for the treatment of BED and obesity (Cottone, Sabino, Roberto et al., 2009).
Meta-analytic studies have found that the treatment option with greatest efficacy for BED is cognitive behavioral therapy (CBT). Remission rates for BED reach 50% using CBT, signifying a substantial decrease or complete remission of binge frequency, as well as improved psychosocial functioning (Wilson, Grilo, Vitousek, 2007
; White, Grilo, O’Malley et al., in press
). Pharmacotherapy has been found to be moderately efficacious as well, although CBT without simultaneous pharmacotherapy has been demonstrated to be most efficacious (Reas & Grilo, 2008
). Despite moderate success in remission of binge frequency, these treatments have not led to substantial reduction in weight; the margins of weight lost through these treatments are usually not substantial enough to significantly reduce one’s BMI or BMI category (Wilson, Grilo, & Vitousek, 2007
). Thus, these treatments may not be efficacious to address the needs of obese individuals seeking to reduce a significant amount of body weight.
A meta-analysis found that nutrition and counseling activities alone may not yield long-term results in obese individuals; however, programs that targeted eating behaviors, physical activity, and counseling yielded greater efficacy. Incorporating a problem-solving component gave additional efficacy for long-term weight loss maintenance (Seo & Sa, 2008
). Of the 24 studies examined in this review, four yielded significant long-term results; three of those studies incorporated a problem-solving component into the paradigm (Seo & Sa, 2008
). An additional meta-analysis found that lifestyle interventions led to significantly reduced body weight, BMI, waist circumference and other health markers as compared to standard care (Galani & Schneider, 2007
Further treatment development may be enhanced through a better understanding of the underlying biological mechanisms of obesity. Leptin, implicated in reward-processing, influences metabolic homeostasis and motivation for feeding behaviors. Endogenous and exogenous leptin administration leads to reduced food consumption (Enriori, Evans, Sinnayah, et al., 2006
; Yip & Potenza, 2009
). Ghrelin, a hormone produced within the lining of the stomach and in the pancreas, stimulates feelings of hunger. Ghrelin and leptin may act together to modulate feeding behaviors, and this relationship may be dysfunctional within obese individuals (Fulton, Woodside, Shizgal, 2000
; Tschop, Weyer, Tataranni, et al., 2001
; Yip & Potenza, 2009
). These and other neurochemicals may represent important targets for the development of novel, complementary and potentially more efficacious treatments for weight loss. An understanding of the history and efficacy of treatment approaches for SUDs is also important in formulating innovative and effective treatment, particularly when considering co-occurring obesity and SUDs.
Some behavioral interventions for SUDs may have relevance for obesity and binge eating disorder (see below). Alcoholics Anonymous was established in 1935 and contributed to the development of behavioral interventions that remain an important part of treatment for SUDs (Lemanski, 2001
). One meta-analysis, utilizing 53 controlled trials of subjects with alcohol and/or substance use disorders, found that CBT produced a significant, although relatively small, treatment effect (Magill & Ray, 2009
). These findings support the use of CBT across a broad range of SUDs, although alternative or combination therapies may enhance the robustness of treatment outcome. Dutra and colleagues (2008)
found positive outcomes for psychosocial interventions for SUDs in a meta-analysis. Contingency Management (CM) programs had the greatest efficacy, with 31% of subjects achieving post-treatment abstinence. Relapse prevention programs yielded high abstinence rates, as well, (39%), although the drop out rate for these programs was 57%. CBT treatment studies reported abstinence rates of 27% with drop out rates of 35% (Dutra, Stathopoulou, Basden et al., 2008
). An important consideration is how well treatment responses are maintained, or gained, over time. For example, CBT in contrast to other behavioral interventions has been shown to have a “sleeper” effect in which treatment outcome improvement may be observed months or years after treatment delivery has ended (presumably related to individuals internalizing, developing and using skills related to CBT overt time). These findings suggest moderate success in treatment through psychosocial interventions, with the possibility of pharmacotherapy and combination therapy offering additional treatment utility.
For nicotine dependence, combination therapy (nicotine replacement patch with an additional component) was found to be significantly more efficacious in smoking cessation treatment than was monotherapy; these results were maintained at 3-, 6-, and 12-month follow-ups (Shah, Wilken, Winkler et al., 2008
). For the treatment of opioid dependence, maintenance programs are often utilized to aid opioid detoxification. Amato and colleagues (2008)
meta-analyzed randomized controlled trials to investigate potential added benefits of pairing psychosocial therapy with pharmacological treatments. The combination therapy was found to have greater efficacy than pharmacological interventions alone. The added psychosocial component may aid in the maintenance of drug-free behaviors to maintain detoxification (Amato, Minozzi, Davoli et al., 2008
Research that investigates non-substance related ways to influence DA systems may help to expand treatment options for individuals with obesity and SUDs, as DA is implicated in reward-processing and reinforcement. Exercise interventions have been found to be effective in increasing DA D2-like dopamine receptors in animal studies. In rodents, exercise training increased striatal DA D2 receptors (MacRae, Spirduso, Walters et al., 1987
; Wang, Volkow, Logan et al., 2001
). In epileptic and spontaneously hypertensive rats, each with pre-intervention low levels of DA, DA levels were normalized in the neostriatum and nucleus accumbens (Sutoo & Akiyama, 2003
). These brain regions are strongly associated with reward processing and addictive disorders (Volkow, Fowler, & Wang, 2003
). Exercise may increase DA function through exercise-related increases in calcium-serum levels (Sutoo & Akiyama, 1996
; Sutoo & Akiyama, 2003
In humans, after high-impact running, subjects were found to have higher catecholamine (DA, epinephrine, and norepinephrine) levels as compared to groups in no exercise and low-impact exercise conditions (Winter, Breitenstein, Mooren et al., 2007
). However, Wang, Volkow, Fowler and colleagues (2000)
found that subjects who underwent 30 minutes of treadmill running exercise did not have significantly higher levels of striatal DA. The methodology may be limited due to the research design in which subjects underwent PET imagery after exercise completion, thus potentially limiting the ability to identify transient DA increases that may have occurred during the exercise. This hypothesis is supported through rodent studies in which rats had DA levels 50%–80% above baseline during exercise as compared to 10%–50% after exercise completion (Meeusen, Smolders, Sarre et al., 1997
; Wang, Volkow, Fowler et al., 2000
). In addition, the subjects who were recruited for this study were physically fit and without medical problems; therefore, it is possible that their baseline DA levels were higher as compared to individuals seeking treatment for obesity or an addictive disorder (Wang, Volkow, Fowler et al., 2000
Aerobic exercise has been associated with better executive functioning. In rodents, exercise training is associated with better performance on memory tasks (Harburger, Kzerem, Frick, 2007
). In one study of overweight children, cognitive processes were better in those subjects who had undergone a high-dose aerobic exercise condition (40 min/5 days a week/15 weeks) (Davis, Tomporowski, Boyle et al., 2007
). Studies seeking to mitigate cognitive decline in aging populations have found that aerobic exercise aids in the maintenance of executive functioning and enhances brain plasticity (Cotman & Berchtold, 2002
). These findings suggest that exercise may be an appropriate component of treatment for obese individuals, as well as those with SUDs, as it may help to increase DA levels in brain regions associated with addictive disorders and to improve executive functioning and inhibition.
An additional alternative treatment involves meditation or mindfulness-based therapy in the treatment of addiction. Meditation, the conscious, effortful practice of calming thoughts and emotions, has been recently investigated in the treatment of addiction (Brewer, Smith, Bowen et al., in press
). Meditating subjects have been found to exhibit increased endogenous DA release in the ventral striatum and increased DA levels were correlated with a reduced readiness for action, a quality that may be helpful in increasing inhibitory responses towards substance and food cravings (Kjaer, Bertelsen, Piccini et al., 2002
). Mindfulness-based interventions that incorporate elements of meditation have shown preliminary promise in the treatment of substance addictions (Brewer, Sinha, Chen et al., in press
) and warrant further study in the treatment of obesity.