درباره نقش غم و اندوه در آسیب شناسی روانی از بی اشتهایی عصبی

Recent models on the development and maintenance of eating disorders propose negative emotions to be important precursors for the occurrence of eating disorder symptomatology. In fact, previous research on bulimia nervosa (BN) and binge eating disorder provides evidence that negative emotions are an antecedent condition for binge eating. However, there is a lack of research examining the influence of negative emotions on restrictive eating and exercising in individuals with anorexia nervosa (AN). In an experimental study, women with AN (n=39) and BN (n=34) as well as a non-eating disordered control group (CG; n=34) watched a sadness-inducing film clip. Before and after the film clip participants rated their current desire to engage in dietary restriction (DTR) and desire to exercise (DTE). Main results reveal that DTR significantly increased after the film clip in women with AN only, while DTE decreased over time in all groups. Results are in line with the notion that negative emotions have a prominent influence on the core eating pathology in AN.

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association (APA), 2013) anorexia nervosa (AN) is an eating disorder characterized by a phobic fear of gaining weight along with an unwillingness to maintain the minimal healthy body weight. Typical behaviors to achieve or maintain underweight include caloric restriction which sometimes even culminates in chronic self-imposed starvation. The severe self-starvation is one reason for the increased morbidity and mortality associated with AN (Fichter et al., 2006, Mitchell and Crow, 2006 and Berkman et al., 2007). With a lifetime prevalence of up to 80% extreme physical activity is another common weight-reducing behavior in individuals suffering from AN (Davis et al., 1997). While a regular amount of exercise has a beneficial effect on mood and physical health (Blumenthal et al., 2007, Deslandes et al., 2009, Archer, 2012 and Morris et al., 2012), research shows that excessive exercise in AN is positively associated with eating psychopathology, hospitalization periods and rates of relaps (Strober et al., 1997, Solenberger, 2001, Peñas-Lledó et al., 2002, Carter et al., 2004 and Bewell-Weiss and Carter, 2010). As such, there is a need for research identifying factors that trigger restriction of food intake and excessive exercise in AN. Models on the maintenance of eating disorders highlight the importance of negative emotions in the occurrence of eating disorder symptomatology (Stice, 2001 and Fairburn et al., 2003). As such, a great body of research exists showing that negative feelings trigger binge eating and purging behavior in bulimia nervosa (BN) as well as binge attacks in binge eating disorder (BED) (Alpers and Tuschen-Caffier, 2001, Hilbert and Tuschen-Caffier, 2007 and Smyth et al., 2007). For example, after an insecurity and sadness-inducing guided imagery task ratings of hunger and desire to binge increased in bulimic patients, whereas no changes were found in healthy controls (Tuschen-Caffier and Voegele, 1999). In contrast to BN and BED, research on the role of negative emotions in the maintenance of anorectic behavior is still sparse. Besides, on a theoretical level it remains controversial whether eating pathology in AN can be influenced by intense mood states. Some theoretical accounts suggest that mood intolerance and maladaptive emotion regulation behavior is rather atypical in individuals with AN compared to other eating disorders (Fairburn et al., 2003). On the other hand, there are recent models on the onset and maintenance of AN that emphasize the emotion regulation functioning of anorectic behavior (Haynos and Fruzzetti, 2011). That is, maladaptive behaviors as dietary restriction and excessive exercise may be triggered by adverse emotional states and might therefore serve as a dysfunctional form of emotion regulation. Empirical evidence supports this notion showing that individuals with AN have more difficulties tolerating and regulating negative emotions compared to healthy controls (Harrison et al., 2009, Wildes et al., 2010 and Svaldi et al., 2012). Moreover, one study (Merwin et al., 2010) reports significant positive correlations of non-acceptance of emotional responses with dietary restriction in women with AN. In qualitative studies AN patients report that main reasons for restriction of food intake include the inability to tolerate adverse emotions, attempts to control negative emotions and efforts to provide positive feelings like pride and security (Serpell et al., 1999, Dignon et al., 2006, Nordbø et al., 2006 and Federici and Kaplan, 2008). Additionally, an ecological momentary assessment (EMA) study (Engel et al., 2005) revealed a prominent correlation between stressful events and affect lability with restrictive behavior and rituals in AN. Further evidence for the reinforcing influence of negative mood on anorectic eating behavior stems from biopsychological studies showing that dietary restraint can have a decreasing effect on the plasma tryptophan availability (Kaye, 2008). The plasma tryptophan modulates brain 5-HT functional activity, which in turn, is thought to have a positive influence on mood (Frank et al., 2001). Regarding excessive exercise, there is indirect evidence of a close linkage between negative emotions and extreme physical activity in individuals with AN. For example, Peñas-Lledó et al. (2002) found that subjects with AN subtyped as high excessive exercisers were characterized by high levels of depression and anxiety compared to those subtyped as low excessive exercisers. Likewise, an EMA study on patients with AN and BN showed that individuals with an increased desire to be physically active are disposed to suffer from a chronically negative affect (Vansteelandt et al., 2007). Notwithstanding, the previously mentioned studies do not allow to draw conclusions about cause and effect. In a very recent study though Wildes et al. (2012) experimentally tested the effects of negative mood on eating disorder symptoms in patients with AN. Specifically, AN participants either watched a negative emotion-inducing film clip or a neutral film clip. Prior to and after the film clip, participants had to rate several self-constructed items on Likert scales ranging from one (agree not at all) to five (completely agree). The items focused on maladaptive thoughts about eating, shape and weight (e.g., I feel fat), as well as urges to engage in eating disorder behaviors typically associated with AN (e.g., I want to restrict). While no changes were found in AN participants allocated to the neutral condition, those allocated to the negative mood condition self-reported a significant increase in eating disorder symptoms following the negative emotion induction. However, as this study summed up different kinds of eating disorder pathology (e.g., urge to restrict, state body image disturbance) it remains unclear which of the specific anorectic symptoms were actually triggered by the induced adverse emotions. This is especially important as previous studies were able to show that negative mood leads to an overestimation of the own body size as well as higher levels of body dissatisfaction (Plies and Florin, 1992 and Baker et al., 1995). Therefore, it is possible that only changes in the items measuring body image disturbances were responsible for the results of Wildes et al. (2012). In light of the research just mentioned, the aim of the present study was to experimentally test the influence of negative emotions on the urge to engage in dietary restriction (DTR) and exercise (DTE) in patients with AN. Based on former studies identifying sadness to be a common pre-binge emotion in BN and BED (Cooper and Bowskill, 1986 and Chua et al., 2004), a sadness-inducing film clip was used as negative emotional stimulus. In addition to an AN group, we included both a non-eating disordered control group and a group of females with BN. The former was included to test for possible effects of mood on eating pathology. The latter was included in order to provide information about differential effects between the two eating disorders, as previous studies reported high rates of syndrome shift (Agras et al., 2000) and similarities (Norman and Herzog, 1983) between AN and BN. With regard to the extensive overlap in the diagnostic criteria particularly between AN of bulimic subtype and BN ( American Psychiatric Association (APA), 2013), analyses comparing AN restrictive and bulimic subtypes were also included to further explore whether the affect regulation model fits both AN subtypes. In line with current models on the onset and maintenance of AN ( Haynos and Fruzzetti, 2011), we predicted that an induction of sadness would lead to an increase of DTR and DTE only in individuals with AN.