Decreased oxytocin plasma levels and oxytocin receptor expression associated with aggressive behavior in aggressive-impulsive disorders

INTRODUCTION

This study aims to enhance the understanding of the association between the phenotypic and endophenotypic characteristics of impulsive-aggressive disorders, through the study of plasma oxytocin (OXT) and oxytocin receptor (OXTR) levels in patients with borderline personality disorder (BPD) and patients with eating disorders (ED), as well as to examine the relationship of OXT system with aggressive behavior in these disorders.

METHODS

68 patients with BPD, 67 patients with ED and 57 healthy control subjects were examined for plasma oxytocin levels and protein expression of OXTR in blood mononuclear cells. Aggressive behavior was assessed using the State-Trait Anger Expression Inventory (STAXI-2). Other self and hetero-aggressive behaviors were also evaluated through interviews.

RESULTS

BPD and ED patients exhibited significantly lower plasma oxytocin levels than control subjects. Furthermore, BPD patients demonstrated significantly reduced expression of OXTR compared to controls. Plasma oxytocin levels negatively correlated with verbal aggression, while OXTR expression was inversely associated with the STAXI trait subscale.

CONCLUSIONS

The findings validate the existence of oxytocin system dysfunction in impulsive-aggressive disorders. They also support the link between low OXT levels in plasma and OXTR expression and the impulsive-aggressive behavior that characterizes these patients in both state and trait situations.

Executive dysfunction in eating disorders: Relationship with clinical features

Eating disorders (ED) are severe mental disorders that may result in significant functional impairment and disability. Neuropsychological studies have consistently found impaired executive function (EF) among ED patients. EF is particularly involved in fundamental skills of daily living and in behavioral and emotional regulation. In this study, impairment of executive functioning is investigated in patients with eating disorders and the associations with clinical features and clinical subtypes are analyzed.

METHOD

75 female patients (m = 22.01 years, sd = 9.15) with eating disorder (43 restrictive anorexia, 30 binge-eating anorexia and 13 bulimia nervosa) and 37 healthy controls (m = 18.54 years, sd = 4.21) were included in the study. An extensive assessment of executive function domains (verbal fluency, set shifting, attention span, selective attention, working memory, inhibitory control and processing speed) was carried out in both groups. Clinical scales for food intake restriction, binge-eating/purging, depression, anxiety and impulsivity were also administered and correlated with scores on executive function tests.

RESULTS

Patients with an ED had significantly lower scores than healthy controls in performance of several executive function tests, particularly in set shifting, interference control and processing speed (p < .01, in all three domains). Executive function impairment was related to anxious, depressive and eating disorder symptoms (p < .05), regardless of clinical subtype.

CONCLUSIONS

Executive function impairment in eating disorders is associated with greater ED symptomatic severity and might involve a negative treatment outcome. Therefore, cognitive remediation techniques should probably be considered in a number of severe patients with ED.

Inflammatory dysregulation in women with an eating disorder: Relationships with altered emotional reactivity

BACKGROUND

Some studies suggest that inflammatory signaling dysregulation may contribute to eating disorder (ED) pathophysiology. However, little is known about the influence of inflammatory response on altered processes seen among patients with ED, such as emotional processing and reactivity.

OBJECTIVES

The objectives were: (a) to investigate the systemic inflammatory response in ED women; and (b) to analyze the role of inflammatory markers in emotional reactivity.

METHOD

Concentrations of several intercellular and intracellular inflammatory mediators (cytokines, prostaglandin by-products and enzymes, TBARS, and MAPK proteins) were quantified in plasma and PBMCs from 68 women with an ED (m = 22.01 years, SD = 9.15) and 35 healthy controls (m = 18.54 years, SD = 4.21). Moreover, emotional reactivity to affective pictures (those without either food or thinness content) was studied using the adult (>18 years old) sample (n = 41).

RESULTS

Between-group differences were revealed for most markers (TNF-α, PGE₂ , COX2, and ratio of activated MAPK proteins), pointing to increased inflammatory response in patients (p < .01). Women with ED showed heightened emotional reactivity, regardless of picture valence. Principal components derived from inflammatory markers showed an explanatory loading on patient's emotional reaction, in terms of valence and arousal.

CONCLUSION

This study corroborates the altered systemic inflammatory response in patients with ED. The inflammatory dysregulation may contribute to ED phenotype, as seen by its relationship with heightened emotional reactivity, even though the inflammatory markers were not evaluated throughout the emotional reactivity protocol.