تست اثربخشی خالص در مقابل مواجهه آینه ای هدایت شده در زنان مبتلا به بولیمیا: ترکیبی از شاخص های غدد و روانی

Background and Objectives Body exposure improves body image problems in women with eating disorders. However it has almost always been combined with other interventions. Thus, the efficacy of body exposure alone (i.e., pure exposure) remains largely unclear. We aimed to compare the efficacy of two body exposure techniques through psychological and neuroendocrine indices recorded within and between successive sessions. Method Twenty-nine women with high body dissatisfaction and diagnosis of bulimia nervosa were randomly assigned to one of two treatment groups: Pure Exposure (n = 14) or Guided Exposure (n = 15). Participants received 6 exposure sessions. After each session, changes in thoughts (positive/negative) and body satisfaction were assessed. Also, we assessed the body discomfort experienced by participants within and between sessions. Finally, the changes in salivary cortisol levels within and between the initial and final treatment sessions were measured. Results Both groups showed a reduction in negative thoughts and a progressive increase in positive thoughts throughout the treatment. However, the increase in body satisfaction and the reduction in subjective discomfort within the sessions were greater in the pure exposure group. The cortisol levels during the initial and final treatment sessions decreased in both groups. Limitations Methodological limitations are reported. Conclusions These results suggest that pure and guided exposures are effective interventions for improving thoughts and neuroendocrine responses, although pure exposure increased more body satisfaction feelings in bulimic women. Subjective discomfort also showed different patterns of change within and along sessions for each treatment. Reasons for these results are discusse

Body exposure has been demonstrated to be an effective technique for reducing body dissatisfaction and negative thoughts and emotions associated with body image in individuals with eating behavior disorders (EBDs) (Trentowska et al., 2013 and Tuschen-Caffier et al., 2003). In this context, several authors have observed that when body exposure exercises are included in cognitive behavior therapy programs or linked to other therapeutic techniques (e.g., mindfulness), they contribute significantly to reducing body dissatisfaction and/or improving other indicators associated with body image disturbances, such as body checking or avoidance behaviors ( Delinsky and Wilson, 2006, Delinsky and Wilson, 2010 and Key et al., 2002). Tuschen-Caffier, Pook, and Frank (2001) developed a body exposure technique in which patients were guided to describe their physical appearance in detail as accurately and as neutrally as possible while watching themselves in a full-length mirror. With this guided neutral description, individuals focused their attention on areas of the body that are normally ignored, including those considered particularly unpleasant. Hilbert, Tuschen-Caffier, and Vögele (2002), using this exposure technique in women with binge-eating disorders, observed that after two treatment sessions, patients' self-esteem increased, and the levels of discomfort, the negative moods and the frequency of the negative thoughts declined. Similar positive findings concerning increased body satisfaction after this type of body exposure were reported by Jansen et al. (2008) in obese adolescents and Trentowska et al. (2013) in women with bulimic symptoms. A different method of mirror exposure for the treatment of body dissatisfaction was recently proposed by Moreno-Domínguez, Rodríguez-Ruiz, Fernández-Santaella, Jansen, and Tuschen-Caffier (2012). These authors examined, in a group of women with high body dissatisfaction, but without EBDs, whether pure exposure to one's own body would be effective in reducing body dissatisfaction compared with the guided exposure developed by Tuschen-Caffier and Florin (2002). It was observed that body dissatisfaction, negative thoughts and feelings of ugliness were reduced in both groups, but subjective discomfort caused by the body was significantly reduced only in the pure exposure group. This type of exposure involves a stronger initial negative emotional reaction followed by a reduction within and between sessions probably reflecting the activation and subsequent habituation/extinction of the dysfunctional emotional responses elicited by viewing one's own body ( Craske et al., 2008, Foa and Kozak, 1986, Foa and McNally, 1996 and Rauch and Foa, 2006). Following Lang's bio-informational model (Lang, 1979), Foa and Kozak (1986) were the first to propose that the therapeutic effects of exposure techniques in the treatment of anxiety disorders are the result of the activation and subsequent modification of the patient's “pathological fear structure” by integration, within the therapeutic context, of information that is inconsistent with that pathological structure. The end result is the reprocessing and modification of the original structure by another non-pathological one. Changes produced in subjective fear and its associated physiological responses within and between sessions are assumed to be indicators that such emotional reprocessing is occurring (Foa and Kozak, 1986, Lang, 1971 and Rachman, 1980). Thus, the success of body exposure therapy might be explained because the discomfort decreases after successive exposure sessions ending the connection between the body and the associated negative emotional responses. However, few studies have evaluated physiological changes that occur within and between successive sessions over the course of treatment based on body exposure. Vocks, Legenbauer, Wächter, Wucherer, and Kosfelder (2007) incorporated such measures in a single mirror exposure session. These authors observed that negative emotions and thoughts increased at the beginning of the session in women with EBDs, in comparison with women without EBDs, decreasing significantly over the session. They also observed significant differences between the groups at baseline cortisol levels, with EBD patients showing higher salivary cortisol concentrations (Vocks et al., 2007). Although they did not examine changes in cortisol after body exposure, the relevance in the area of eating disorders of the role of the stress response, mediated by activation of the hypothalamic-pituitary-adrenal axis through cortisol release, is well documented (Koo-Loeb et al., 1998, Lo Sauro et al., 2008 and Neudeck et al., 2001). Koo-Loeb et al. (1998) reported elevated cortisol levels, together with more perceived stress, worse mood, and greater anxiety, in women with bulimia nervosa (BN), compared to control women. Additionally, Neudeck et al. (2001) observed that the abnormal levels of cortisol in women with BN disappeared after weight normalization and the stabilization of symptoms after treatment. The present investigation aims to replicate and extend the pilot study by Moreno-Domínguez et al. (2012) comparing the efficacy of pure exposure and guided exposure procedures in healthy women with high body dissatisfaction focusing on the cognitive and emotional components. Participants were a group of women with bulimia nervosa and body dissatisfaction. We included neuroendocrine (cortisol) assessment before and during the initial and final treatment session, together with cognitive and affective measures within and between sessions. We also extended the number of treatment sessions from five to six. First, we predicted that pure exposure, based on Foa and Kozak's paradigm of anxiety response extinction ( Foa & Kozak, 1986), would be as effective as guided exposure in decreasing body dissatisfaction levels and negative thoughts, simultaneously increasing positive thoughts. Second, according to the results of the study by Moreno-Domínguez et al. (2012), we expected that the reduction in subjective discomfort within each treatment session would be larger and quicker in the pure exposure than in the guided exposure method. Finally, regarding cortisol, we assumed that repeated mirror exposure would reduce the stress response caused by viewing one's own body within and between the initial and final treatment sessions in both exposure methods.

Our study showed that pure exposure might be a useful therapeutic strategy for reducing body dissatisfaction and cortisol response and improving the positive emotions and thoughts among patients with BN. This exposure technique is simple and easy to implement compared with other techniques. Therefore, supporting preventive and treatment programs for EBDs with this tool could enhance their efficacy. Also, there was a similar improvement of guided exposure in reducing negative thoughts and increasing positive thoughts and body satisfaction. Thus, both procedures are effective, although they may facilitate therapeutic change through different mechanisms. If so, both procedures may be useful in different stages of the treatment. Accordingly, we suggest the need for future studies to test whether a combination of pure and guided exposure could be more effective than each procedure alone in reducing body dissatisfaction and other body image disturbances in BN and other clinical groups.