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Abstract: Objective: We explored interaction effects involving polymorphisms of targeted dopamine system genes and selected forms of childhood abuse (sexual, physical and emotional) acting upon severity of binge-eating and psychopathological symptoms in women with Bulimia-Spectrum Disorders (BSDs). Methods: Women diagnosed with a BSD (n = 216) were assessed for childhood traumata, eating-disorder (ED) symptoms, and selected psychopathological features (sensation seeking, impulsivity, compulsivity and affective instability), and then provided blood samples for genotyping of main polymorphisms of dopamine-2 receptor (DRD2), dopamine transporter (DAT1) and catechol o-methyltransferase (COMT) genes. Results: Sensation Seeking was elevated in carriers of the low-function allele of the DRD2 Taq1A polymorphism who also reported childhood sexual abuse, relative to that in individuals showing other combinations of alleles and abuse exposures. In addition, carriers of a low-function allele of COMT scored higher on compulsivity, lower on impulsivity, and marginally lower on frequency of binge-eating than did individuals in whom the allele was absent. Discussion: Our results suggest that genes acting within the dopamine system may contribute, either directly or indirectly (i.e., in interaction with traumatic childhood experiences), to variations in the presentation of comorbid traits and, possibly, of bulimic symptoms. [Copyright &y& Elsevier]

Abstract: Context: Efforts to classify eating-disordered individuals based on concurrent personality traits have consistently converged on a typology encompassing “over-regulated”, “dysregulated”, and “low psychopathology” subgroups. In various populations, evidence has associated personality variations of an “over-regulated/dysregulated” type with differences on serotonin-system indices, and specifically, with different loadings of serotonin transporter promoter regulatory region polymorphism (5HTTLPR) genotypes and alleles. We explored the extent to which an empirical, trait-defined typology of eating-disordered individuals coincided systematically with variations in 5HTTLPR, assayed using biallelic and triallelic models. Method: We tested 185 women with a DSM-IV eating disorder (108 with Bulimia Nervosa, 17 Anorexia Nervosa, and 60 an Eating Disorder Not Otherwise Specified) and 93 with no eating disorder on measures reflecting psychopathological traits and 5HTTLPR (biallelic and triallelic) genotypes and alleles. Results: The highest-function, triallelic (LA/LA) genotype occurred significantly more frequently among eating-disordered individuals than among controls. However, a more fine-grained analysis suggested that this association was attributable to the fact that, among eating-disordered participants, those displaying an “Inhibited/Compulsive” profile (derived using latent class analysis) were more likely than those of a “Dissocial/Impulsive” or a “Low Psychopathology” group to carry the triallelic 5HTTLPR gain-of-function LA allele and to be LA/LA homozygotes. Discussion: This study’s empirically derived classes coincide with interpretable differences on genetic indices—associating an “Inhibited/Compulsive” group with 5HTTLPR gain-of-function genotypes (and alleles) that have elsewhere been linked to trait compulsivity. The findings, furthermore, suggest that 5HTTLPR, by influencing personality-trait manifestations may, in turn, influence eating-disorder risk and symptom expression. [Copyright &y& Elsevier]

Abstract: We explored the influence of interactions between polymorphisms acting upon postsynaptic receptors (DRD2 TaqA1 rs1800497 and DRD4 7R) and dopamine regulators (COMT rs4680 and DAT1) on the expression of eating symptoms and personality traits in women with bulimia-spectrum eating disorders. We had 269 bulimic women provide blood for genetic assays, and measured eating-disorder symptoms and psychopathological traits using structured interviews and self-report questionnaires. We observed two epistatic interactions on symptom indices: interactions (in predicted directions) of DRD2 by DAT were seen on Body Mass Index (p =.023), and of DRD4 by COMT on self-harming behaviors (p =.014) —with genetic effects that would correspond to reduced dopamine transmission coinciding with more-pathological scores. Our findings suggest that genes acting in the dopamine system interact to influence both eating-related and personality psychopathology, with the result that lower levels of dopamine neuro-transmission correspond to increased psychopathology and body mass in women with bulimia-spectrum disorders. We discuss the implications of our observations. [Copyright &y& Elsevier]

Abstract: Past research has suggested that negative affect may be a causal factor for eating disordered behaviors. More specifically, research has shown that anger appears to be one aspect of negative affect that is particularly relevant in bulimic patients. Previous studies have also shown that the relationship between negative affect and eating disordered behaviors may partially depend upon personality variables such as impulsivity. The present study examined whether the relationship between anger and eating disordered behaviors is moderated by impulsivity. Subjects completed an ecological momentary assessment (EMA) protocol for an average of 2 weeks. Findings revealed that overall antecedent anger level and the variability of antecedent anger predicted binge-eating episodes and that these relationships were moderated by participants’ level of impulsivity. These findings suggest that personality variables impact the way that anger and eating behaviors relate. They also suggest that the variability of antecedent anger may be a fruitful avenue for future research for those interested in causal variables associated with bulimia nervosa. [Copyright &y& Elsevier]