Association between neuroendocrinological parameters and learning and memory functions in adolescent anorexia nervosa before and after weight recovery

Abstract

A growing body of evidence indicates that hormones play an important role in learning and memory functions as well as in mood modulation. During the acute stage of anorexia nervosa (AN), weight loss has a significant effect on serum levels of estrogen, thyroid hormones, and cortisol. Furthermore deficits in learning and memory functions are evident in patients with eating disorders during emaciation. Hormonal and neuropsychological alterations at least partly remit during weight restoration. We investigated the association between learning and memory functions as well as mood and neuroendocrinological parameters before and after weight gain in adolescent AN. Twenty-eight female subjects with AN, diagnosed according to DSM-IV, were examined before and after weight recovery. Both investigations took place while the patients were receiving hospital treatment, and the results were compared to a control group consisting of 18 age- and IQ-matched normal-weight female adolescents also tested twice within 4 months. Verbal memory and learning were assessed by a German paper-pencil-test (LGT). We performed correlation calculations between neuropsychological functions and depressive symptoms and estrogen, cortisol and free triiodothyronine (fT₃) in the plasma at both time points. Compared to normal controls adolescents with AN performed worse in one subtest of the LGT which requires the verbal reproduction of figural material across both time points. Verbal learning was positively correlated with estrogen levels after weight recovery. Depressive symptoms of AN patients significantly decreased during weight rehabilitation and correlated negatively with fT₃ at T₁. We did not find a relationship between cortisol levels and neuropsychological functions. We observed subtle memory impairments and depressive symptoms in subjects with adolescent AN associated with starvation-induced estrogen and triiodothyronine deficits, respectively. Normalization of body weight and resuming of menses is needed to restore learning and memory functions as well as to alleviate depressive symptoms.