ABSTRACT
OBJECTIVE: An insular involvement in the pathogenesis of anorexia nervosa (AN) has been suggested in many structural and functional neuroimaging studies. This magnetic resonance spectroscopy (MRS) study is the first to investigate metabolic signals in the anterior insular cortex in patients with AN and recovered individuals (REC). METHOD: The MR spectra of 32 adult women with AN, 21 REC subjects and 33 healthy controls (HC) were quantified for absolute N-acetylaspartate (NAA), glutamate + glutamine (Glx), total choline, myo-inositol, creatine concentrations (mM/L). After adjusting the metabolite concentrations for age and partial gray/white matter volume, group differences were tested using one-way multivariate analyses of variance (MANOVA). Post-hoc analyses of variance were applied to identify those metabolites that showed significant group effects. Correlations were tested for associations with psychometric measures (eating disorder examination), duration of illness, and body mass index. RESULTS: The MANOVA exhibited a significant group effect. The NAA signal was reduced in the AN group compared to the HC group. The REC and the HC groups did not differ in metabolite concentrations. In the AN group, lower NAA and Glx signals were related to increased weight concern. DISCUSSION: We interpret the decreased NAA availability in the anterior insula as a signal of impaired neuronal integrity or density. The association of weight concern, which is a core feature of AN, with decreased NAA and Glx indicates that disturbances of glutamatergic neurotransmission might be related to core psychopathology in AN. The absence of significant metabolic differences between the REC and HC subjects suggests that metabolic alterations in AN represent a state rather than a trait phenomenon.
ABSTRACT
A categorical approach to the study of amygdala volumes in specific neuropsychiatric disorders leads to contradictory findings. In an alternative dimensional approach, we tested the hypothesis that amygdala volume loss represents specific dimensions of affective syndromes in patients with epilepsy. One hundred sixty patients with chronic therapy-refractory epilepsy were carefully diagnosed for psychiatric symptoms. Fifty-three patients without any lifetime psychopathology (n=24), with dysphoric disorder of epilepsy (n=12), or with major depressive disorder (n=17) were included. Amygdala and hippocampal volumes were measured using established protocols. Amygdala volumes were significantly reduced in patients with dysphoric disorder of epilepsy and correlated significantly with core symptoms of dysphoric disorder of epilepsy, that is, emotional instability, dysphoria, irritability, and aggression. Our finding supports a dimensional concept of the meaning of brain alterations and validates the clinical concept of dysphoric disorder of epilepsy.