Asymmetric cognitive function in anorexia nervosa

Antagonism for NPY signaling reverses cognitive behavior defects induced by activity-based anorexia in mice

Patients with AN often express psychological symptoms such as body image distortion, cognitive biases, abnormal facial recognition, and deficits in working memory. However, the molecular mechanisms underlying the impairment of cognitive behaviors in AN remain unknown. In the present study, we measured cognitive behavior using novel object recognition (NOR) tasks and mRNA expressions in hypothalamic neuropeptides in female C57BL/6J mice with activity-based anorexia (ABA). Additionally, we evaluated the effects of antagonists with intracerebroventricular (icv) administration on the impairment of cognitive behavior in NOR tasks. Our results showed that NOR indices were lowered, subsequently increasing mRNA levels of agouti-related peptide (AgRP) and neuropeptide Y (NPY), and c-Fos- and AgRP- or NPY-positive cells in the hypothalamic arcuate nucleus in ABA mice. We also observed that icv administration of anti-NPY antiserum (2 µl), anti-AgRP antibody (0.1 μg), and Y5 receptor antagonist CPG71683 (15 nmol) significantly reversed the decreased NOR indices. Therefore, our results suggest that increased NPY and AgRP signaling in the brain might contribute to the impairment of cognitive behavior in AN.

Intellectual function in patients with anorexia nervosa and bulimia nervosa

OBJECTIVE

This study aimed to examine cognitive function in individuals with anorexia nervosa (AN) and bulimia nervosa (BN) on the basis of IQ measures, indexes and subtests of the Wechsler Adult Intelligence Scale – Third Edition (WAIS-III).

METHODS

A total of 41 patients with AN, 40 patients with BN and 40 healthy controls (HC), matched for sex, age and education, were recruited consecutively to complete the WAIS-III.

RESULTS

The AN group showed a significantly lower performance than the HC group on most global measures and on eight of the 13 administered subtests. Minor differences in verbal function were detected between the BN group and the HC group.

CONCLUSION

The patients with eating disorders showed normal intellectual functions compared with the normative population. However, the AN group displayed a consistently lower performance than the matched HC group, which performed above normative means. The BN group performed at a level between that of the AN and HC groups.

Heightened sensitivity to reward and punishment in anorexia nervosa

OBJECTIVE

The objective of this study is to test whether females with anorexia nervosa (AN) have increased sensitivity to punishing or rewarding stimuli, behaviors that could drive high self-control and anxious, avoidant behaviors.

METHOD

Sixty-four females completed the study: 33 control females (CFs, mean age 19.7 years) and 31 females with AN (mean age 19.6 years). Participants completed diagnostic exams, questionnaires for eating disorder severity and personality, and the Sensitivity to Punishment/Sensitivity to Reward Questionnaire (SPSRQ).

RESULTS

Females with AN scored higher than CFs on SPSRQ sensitivity to punishment (p < 0.00001) and sensitivity to reward (p = 0.005). Females with AN without anxiety or depression continued to have increased SPSRQ scores compared to CFs.

DISCUSSION

This is the first study comparing the SPSRQ in females with AN and CFs. Results suggest that reward and punishment sensitivity are increased in females with AN and could be potential trait markers. It is possible that harm-avoidant, anxious behaviors in females with AN are related to this heightened sensitivity.

Autism and anorexia nervosa: Two facets of the same disease?

We compiled data included in the Primal Health Research Database (www.primalhealthresearch.com) to test the hypothesis that when two pathological conditions or personality traits share the same critical period for gene-environment interaction, we should expect further similarities, particularly from clinical and pathophysiological perspectives. The keywords 'autism' and 'anorexia nervosa' (but not bulimia nervosa) lead to studies suggesting that for both conditions the perinatal period is critical. We take this example to look at other possible links between these pathological entities. From a clinical perspective, several teams have independently emphasized the importance of autistic traits in anorexia nervosa. Deficits in the processing of oxytocin have been demonstrated in both cases. Autistic groups have significantly lower blood oxytocin levels than normal groups, and oxytocin levels increase with age in the normal group only. In autistic groups there is a high ratio of intermediates of oxytocin synthesis (OX-T) to the nonapeptide oxytocin (OT). On the other hand, it has been reported that the level of oxytocin in the cerebrospinal fluid of anorexic women is significantly lower than the level of oxytocin in bulimic and control subjects. Scanning data reveal similar asymmetric functions with left hemisphere preponderance in autistic spectrum disorders and anorexia. A comparative study of the mirror neurons systems is another promising avenue for research. Such an accumulation of similarities from a great diversity of perspectives suggests that anorexia nervosa might be considered a female variant of the autistic spectrum. A plausible interpretation is that prenatal exposure to male hormones might protect against the expression of this disease: girls who have a twin brother are at low risk for anorexia nervosa, compared with girls who have a twin sister, and with controls; furthermore genetic linkage analyses do not detect change on the X chromosome. From an overview of the database, the perinatal period appears to be critical for all disorders related to the capacity to love (including love of oneself), to the potential for aggression (including self-destructive behaviours), or to sociability. Is the perinatal period critical for the organisation of the oxytocin system? This is an important question at a time when we learn that the widely used synthetic oxytocin can probably diffuse across the placenta. On the other hand, where the genesis of metabolic types is concerned, it is prenatal life that appears to be critical.

Implications of starvation-induced change in right dorsal anterior cingulate volume in anorexia nervosa

OBJECTIVE

Converging evidence suggests a role for the anterior cingulate cortex (ACC) in the pathophysiology of anorexia nervosa (AN). This study sought to determine whether ACC volume was affected by starvation in active AN and, if so, whether this had any clinical significance.

METHOD

Eighteen patients with active AN and age- and gender-matched normal controls underwent magnetic resonance imaging (MRI). Sixteen patients (89%) with AN had intelligence quotients (IQ) testing at intake, 14 (78%) had repeat MRIs after weight normalization, and 10 (56%) had outcome data at 1-year posthospitalization.

RESULTS

Right dorsal ACC volume was significantly reduced in active AN patients versus controls and was correlated with lower performance IQ. While ACC normalization occurred with weight restoration, smaller change in right dorsal ACC volume prospectively predicted relapse after treatment.

CONCLUSION

Reduced right dorsal ACC volume during active AN relates to deficits in perceptual organization and conceptual reasoning. The degree of right dorsal ACC normalization during treatment is related to outcome.

Dynamics of emotional expression in autobiographic speech of patients with anorexia nervosa

Emotional disturbances in persons with anorexia nervosa have mainly been documented using static descriptions. This study presents the temporal organisation of emotional expression in autobiographical speech of anorexic patients and thereby provides a first attempt to quantify the dynamics of emotions in patients' speech. The temporal pattern of emotional expression for persons with anorexia nervosa was studied after transforming the autobiographical narratives of 14 patients and 13 matched controls into symbolic sequences of positive, negative, and neutral emotional expressions. These symbolic sequences of emotional states and silences were analyzed using static and dynamic indices. Static indices showed that patients with anorexia nervosa expressed more negative emotions and fewer neutral states than control participants. Dynamic indices showed in patients' speech a cycle of negative emotions and silence. These results showed specific dynamics of emotional expression in persons with anorexia nervosa characterised by the presence of negative emotional perseveration. The possible clinical implications of these findings are discussed.

Kognitive Veränderungen beim Fasten

Zusammenfassung. Theoretischer Hintergrund: Auf Grund der extrem eingeschränkten Kalorienzufuhr beim Fasten kommt es zu verschiedenen hormonellen- und Stoffwechselveränderungen. Fragestellung: Sind kognitive Funktionen bei einer Fastendauer von 72 Stunden beeinträchtigt? Methode: Es wurden 15 Teilnehmer eines Buchinger-Fastenkurses und eine nach Geschlecht, Alter und höchstem Schulabschluss parallelisierte Kontrollgruppe an zwei Untersuchungszeitpunkten neuropsychologisch getestet (Aufmerksamkeit, visuo-konstruktive Fähigkeiten, konditional-assoziative Lernfähigkeit, Befindlichkeit). Ergebnisse: In der Fastengruppe ergaben sich nach 72 Stunden signifikant schlechtere Leistungen in Aufmerksamkeitstests und im konditional-assoziativen Lernen. Das allgemeine Befinden war jedoch deutlich besser ausgeprägt als in der nicht fastenden Kontrollgruppe. Das verbale Lernen, die verbale und visuo-räumliche Merkfähigkeit sowie die Visuokonstruktion waren dagegen unbeeinträchtigt. Schlussfolgerung: Bereits nach einer extremen Nahrungseinschränkung von 72 Stunden zeigen sich selektive Beeinträchtigungen der kognitiven Funktionen, welche in milder Ausprägungen denen von Anorexiepatientinnen entsprechen.

Differentiation of cognitive and motor aspects in a digit symbol substitution test in Anorexia nervosa patients, before and after weight restoration

BACKGROUND

In a previous study, using computerized analysis of fine motor behaviour, seriously underweight anorexia nervosa patients in the early phase of treatment were found to have shorter reaction times, but not movement times, in experimental drawing and copying tasks. These differences persisted with weight restoration.

SAMPLING AND METHODS

Using computerized analysis of writing and drawing behaviour during the performance of a Digit Symbol Substitution Test, 15 anorexia nervosa patients were compared with 15 normal controls, matched for age, sex and educational level. Patients were retested after weight restoration, as were controls after a similar interval.

RESULTS

Patients turned out to be superior in the cognitive, but not in the motor aspects of the Digit Symbol Substitution Test. These differences persisted after weight restoration. A practice effect, due to repeated testing, was found in both groups, which turned out to be cognitive in nature.

CONCLUSIONS

The findings show that this new technique can add to the interpretation of classic neuropsychological tests. The results are compatible with previous findings of intact or even superior functioning in anorexia nervosa patients on neuropsychological tasks requiring considerable cognitive effort.

Zur Neuropsychologie und Neurophysiologie der Anorexia nervosa

Zusammenfassung. Theoretischer Hintergrund: Konvergierende neurowissenschaftliche Befunde zur Anorexia nervosa deuten darauf hin, dass Veränderungen im Zentralnervensystem mit Störungen des Essverhaltens assoziiert sein können. Fragestellung und Methode: Es soll ein Überblick über ausgewählte empirische Befunde aus den Bereichen Neuroanatomie, Neurophysiologie und Neuropsychologie gegeben werden. Ergebnisse und Schlussfolgerungen: Trotz der teilweise heterogenen Befundlage belegen die Ergebnisse, dass bei der Anorexie strukturelle und funktionelle cerebrale Veränderungen vorliegen können, denen möglicherweise eine Rolle bei der Genese und Aufrechterhaltung der Erkrankung zukommt.

Neurocognitive functioning in subjects with eating disorders: the influence of neuroactive steroids

BACKGROUND

Neuropsychological studies in subjects with eating disorders (EDs) have reported conflicting findings, which might be accounted for by several confounding variables, including neuroendocrine changes.

METHODS

General abilities, executive functions, attention, and noneffortful learning were assessed in 45 patients with EDs and 45 healthy comparison subjects (HCS). Plasma levels of 17beta-estradiol, cortisol, allopregnanolone, dehydroepiandrosterone and its sulfate metabolite (DHEA and DHEAS) were evaluated in a subsample of patients and HCS. The influence of clinical, demographic, and neuroendocrine variables on neurocognitive performance was explored.

RESULTS

Patients were slower than HCS on noneffortful learning and more accurate on a spatial executive task. DHEA and DHEAS were increased and positively correlated with accuracy on the executive task, while cortisol positively correlated with speed of noneffortful learning.

CONCLUSIONS

A subtle impairment of noneffortful learning is the only neuropsychological deficit in patients with EDs. Changes in neuroactive steroids influence neurocognitive performance.

Cognitive processing of anorexic patients in recognition tasks: an event-related potentials study

OBJECTIVE

We used event-related potentials (ERPs) to test whether anorexic subjects have difficulties in filtering out irrelevant stimuli in controlled information processing tasks.

METHODS

ERPs from 12 anorexic patients were recorded during recognition of simple and complex body images and simple and complex geometrical shapes.

RESULTS

Anorexic subjects had larger P300 amplitudes for frequent stimuli during body images and simple geometrical shape recognition tasks. Longer P300 latencies were also found in simple geometrical shape recognition tasks, although task complexity had no effect on the P300 latency and amplitude.

DISCUSSION

These results are explained in terms of nonspecific hyperarousal in mental anorexia and relative inability to filter out irrelevant stimuli leading to working memory saturation.

Neurocognitive evidence favors "top down" over "bottom up" mechanisms in the pathogenesis of body size distortions in anorexia nervosa

Perceptually-based disturbances in body image, or body size distortions, have been posited to occur in anorexia nervosa (AN). Perception does not result from a simple flow of sensory information from periphery to cortex ("bottom-up" processing), but involves the selection of inputs most likely to be relevant in light of an individual's experience and expectations ("top-down" processing). Most investigations of body size distortion in AN have used procedures likely to engage top-down processing, raising the possibility that attitudinal disturbances may play a role. To our knowledge, there have been no studies that assess the presence, in AN, of neurocognitive deficits associated with neurologically based disturbances in body schema. Such deficits, if found, could provide evidence of body image distortion unlikely to result from top-down processing. We tested 20 inpatients with AN on measures of proprioception, finger identification, right/left orientation, general cognition and eating disorders symptomatology, both before and after treatment. Matched normal controls were tested on the same measures over the same time intervals. Significant differences between the two groups occurred only prior to treatment, and only on those measures which involved executive, in addition to more body-schema-specific functions. This suggests that patients with AN do not have enduring deficits in the domain of body-schema, but may have subtle cognitive dysfunction, in the acute state, which is not specific to, but can interact with processing of body-schema-related information. This, in turn, suggests that their body image distortion may not be secondary to bottom-up perceptual disturbances.

Season of birth in females with anorexia nervosa in Northeast Scotland

OBJECTIVE

To determine whether patients with anorexia nervosa exhibit an abnormal pattern in their season of birth.

METHOD

Case records of female patients presenting to secondary services in Northeast Scotland from 1965 to 1997 who received a clinical diagnosis of anorexia nervosa were examined. The months of birth of the 446 anorexic patients with a confirmed diagnosis were compared with 5,766 female control subjects born locally in 1951, 1961, 1971, and 1981.

RESULTS

Patients with anorexia nervosa had an excess of births in the first 6 months of the year (p =.013). The greatest excess was from March to June.

DISCUSSION

This provides further evidence that birth dates of anorexics peak in the late spring and early summer. There are parallels with the epidemiology of schizophrenia. The evidence suggests that a seasonally fluctuating factor, most plausibly an intrauterine effect of common infectious agents during the winter months, is of etiological significance.

Are there specific disabilities of number processing in adolescent patients with Anorexia nervosa? Evidence from clinical and neuropsychological data when compared to morphometric measures from magnetic resonance imaging

The cerebral effect of the loss of body weight in Anorexia nervosa (A.n.)--the so-called 'pseudoatrophy'-- is well known and confirmed by several neuroimaging studies. Another subject of intensive research has been whether A.n. leads to specific cognitive impairments, especially of intelligence. However, there are no previous studies on the relations between the cerebral changes, intelligence performance, and disorders of number processing in adolescent patients with A.n. We examined n = 18 inpatients with A.n. (means at admission: age 14.5 years, SD 1.59; BMI 14.9, SD 1.36), diagnosed according to ICD-10 criteria at three different timepoints: at admission to treatment (T1), with 50 % restoration of their normal weight (T2), and with normal weight (T3). At each timepoint, a cerebral MRI scan was obtained. Based on the MRI we determined the volume of the external and internal cerebrospinal fluid cavities, fissures of Sylvius, the surface of mesencephalon and pons, and surface and length of the Corpus callosum. At T1 and T3, a neuropsychological examination was conducted including tests of the general fluid ability and general cristallized ability of intelligence (CFT-20), as well as tests of vocabulary and number processing. The same instruments were given to a group of matched controls (means: age 15.8 years, SD 1.57; BMI 20.5, SD 2.3) at one timepoint. We could show a significant volume difference of the lateral ventricles and the fissure of Sylvius between patients at T, and controls, which abaded with the patient's weight restoration. But a significant surface deficit of the mesencephalon, and less pronounced in the pons, persisted to T3 in patients when compared to controls, suggesting a selectivity of the cerebral changes in A.n. The neuropsychological examinations revealed significant changes in test performance for both the general intelligence test and number processing. At T1 the number processing performance was significantly lower in patients when compared to controls. However, when the patients had restored their normal body weight, we found 2.02 % with a 'severe disorder of arithmetic skills' and 4.45 % with a 'functional disorder of arithmetic skills'. This combined prevalence of 6.47 % of patients with a subnormal arithmetic performance is analogous to that in the normal population.

Anorexia nervosa remission during an episode of encephalitis

OBJECTIVE

The case described suggests that there may be a neurobiological aspect to the etiology of anorexia nervosa (AN) and that development of new pharmacological treatment strategies aimed at the central nervous system (CNS) may be possible.

METHOD

A 25-year-old female with AN lost her anorexic behaviors following an episode of encephalitis with associated hypoxic brain injury. Once the neurological sequelae resolved, the anorexic behaviors returned.

RESULTS

During recovery, the patient's weight increased from 37.8 to 51.1 kg and body fat content by skinfold measurement increased from 7.5% to 18.5%.

DISCUSSION

If a neurophysiological mechanism underlying AN could be identified, it might be possible to devise new treatment options.

Neuropsychological assessments before and after treatment in patients with anorexia nervosa and bulimia nervosa

In psychiatric patients the identification of cognitive deficits which predict a poor clinical outcome is important for the development of specific treatment strategies aimed at the amelioration of these impaired cognitive functions to increase the likelihood of full clinical remission. However, such attempts are absent in bulimia nervosa (BU), are scarce in anorexia nervosa (AN) and, furthermore, provide conflicting results. In the present prospective study we investigated the neuropsychological demands in 12 patients with AN and in 14 patients with BU before, during, and after a treatment period. At the initial testing session, both patients samples showed similar and impaired performance levels on tasks measuring attentional demands and problem solving abilities, while their mnemonic functions were preserved. At the final testing session, which took place 7 months thereafter, the impaired cognitive functions had improved to a similar degree in the AN and the BU subgroups. However, although the eating disorder symptomatology had ameliorated in parallel, no direct associations could be established with the initial neuropsychological demands and their rectification, respectively. On an individual level, 11 patients initially showed obvious cognitive deficits. However, the clinical characteristics of this subgroup differed not from that found in the 15 'good performers'. These findings indicate that the cognitive functions in the acute AN and BU are similarly impaired, but also ameliorate in a similar manner with clinical remission. Because no associations were obvious between cognitive and clinical rectifications, significant contributions of mediating factors (e.g., changes in metabolic brain turnover and in steroid hormones) are suggested.

Brain glucose metabolism in eating disorders assessed by positron emission tomography

OBJECTIVE

As anorectic and bulimic patients present similar clinical and neurobiological symptoms, the purpose of this study was to compare brain glucose metabolism at rest in these patients.

METHODS

Positron emission tomography with (18-F)-fluorodeoxyglucose was used to evaluate cerebral glucose metabolism (CMRglu) in 10 normal-weight bulimic women, in 10 underweight anorectic patients, and in 10 age- and sex-matched healthy volunteers.

RESULTS

Absolute global cortical glucose activity was significantly lower in anorectic patients compared with bulimic and control subjects. Anorectic patients compared with normal control subjects also showed higher relative CMRglu in the inferior frontal cortex and in the basal ganglia, and putamen and caudate relative hypermetabolism when compared with bulimic patients. Thus, both eating disorder groups differed from control subjects in low relative parietal values of glucose.

DISCUSSION

While absolute global metabolism seems to be related to weight loss, we can hypothesize either a common parietal cortex dysfunction in eating disorders or a particular sensitivity of this cortex to consequences of eating disturbances.

The intellectual functioning of adolescents with anorexia nervosa and bulimia nervosa

The aim of this study was to investigate the intellectual functioning of a large group of eating disordered adolescents in order to test two hypotheses, viz, that the intellectual functioning of eating disordered adolescents conforms to the normal distribution, and that eating disordered adolescents do not perform better in verbal abilities than in nonverbal abilities. Standard intelligence tests were applied to 190 consecutive out- and inpatients with eating disorder diagnoses. The results were compared with those of a group of patients with other disorders, similar in age, sex, SES, and year of admission. The IQ of the eating disordered patients was significantly higher than that of patients in the comparison group. Patients in the comparison group and bulimic patients, but not anorexic patients, showed better nonverbal than verbal intellectual performance.

Assessment of brain function in adolescent anorexia nervosa before and after weight gain

This study assessed brain function in 20 adolescent females with anorexia nervosa (AN) and 20 controls using event-related potentials (ERPs) and a battery of neuropsychological tests. In the AN group, N4 latencies for a nonverbal memory task were significantly longer than for a verbal task, and P3 latencies for the verbal task were significantly longer among anorexics as compared to controls. On the nonverbal task, the AN group failed to show a right > left hemispheric asymmetry for P3 amplitudes which was observed for controls. These group differences for P3 latency and amplitude were particularly pronounced in the central-parietal region of the head. Body Mass Index (BMI) in the anorexic group significantly predicted N4 amplitudes for the verbal task in the left hemisphere and P3 amplitudes for the nonverbal task in the right hemisphere. The two groups did not differ on any of the tests used to assess neuropsychological functioning. Eight nutritionally recovered patients and their matched controls were retested using the same procedures. Anorexics showed larger P3 amplitudes for the verbal as compared to the nonverbal task at follow-up. These findings provide evidence for localized brain dysfunction in anorexia nervosa that only partially normalizes with weight gain.

Cognitive functioning, weight change and therapy in anorexia nervosa

Anorexia nervosa is associated with impairments in cognitive function which have been hypothesized to be fundamentally attentional in nature. The current study investigated whether therapy and weight gain affect these impairments. A group of anorexics (N = 12) completed a battery of cognitive performance tasks and self-report measures of psychopathology on three occasions, over the course of 12 weeks of in-patient treatment. A non-clinical control population (N = 17) completed the same measures. The anorexics improved on all measures of psychopathology and affective state as a result of therapy. Anorexics displayed poorer recall, reaction times, and motor speed than the control subjects. Although there was a gain in weight over the course of therapy, there was no corresponding improvement in cognitive performance. Impaired task performance in anorexics was not directly related to their psychopathology or affective state.

Neuropsychological and structural brain changes in anorexia nervosa before and after refeeding

The neuropsychological performance and Magnetic Resonance Imaging (MRI) brain appearance of a consecutive series of 46 in-patients with anorexia nervosa (AN) was compared with that of 41 normal-weight controls. The groups were matched for sex, age, estimated pre-morbid intelligence and education. AN patients who had gained at least 10% of their body weight were retested and rescanned. Controls were retested after a similar interval. The AN group performed significantly worse than the controls on tasks measuring attention, visuospatial ability and memory. On tasks assessing flexibility and learning, no group differences were evident although an examination of deficits in individuals revealed that more anorexics were impaired on both. Following treatment, the AN group improved relative to the control group only on those tasks assessing attention. Comparison of MRI measures showed a significant proportion of anorexics had enlarged lateral ventricles and dilated sulci on both cortical and cerebellar surfaces, but no dilatation was evident for the third and fourth ventricular measures. Improvements were found after treatment on some of the radiological measures but many differences remained. Relationships between morphological brain changes and cognitive impairments were weak. Lower weight, but not duration of illness, was associated with poorer performance on tasks assessing flexibility/inhibition and memory, and with greater MRI ventricular size.

Theoretical and empirical considerations on the relation between 'body image', body scheme and somatosensation

The authors first discuss possible interactions between the hitherto neglected neurophysiological and neuropsychological factors and the traditionally accepted cognitive and affective factors in 'body image' formation. They then report on a study of the relation between body size perception (video distortion technique, image marking procedure, kinaesthetic size estimation apparatus) and somatosensation (thermal, pain and vibration thresholds) in young women. Included in the study were questionnaires on eating behaviour and motivation, body attitude or body satisfaction, and depressive mood and thoughts. Neither the somatosensory nor the questionnaire variables explained the difference between 'overestimators' and 'underestimators' of body size. However, these variables did explain the difference between 'good perceivers' and 'poor perceivers' (degree of deviation from actual body size) in the video distortion technique, with a somewhat larger contribution by the somatosensory variables. The latter finding, although clearly preliminary, should stimulate further investigations of the relationship between somatosensory variables and body size perception.

Is anorexia nervosa a neuropsychological disease?

Evidence for central nervous system, and more particularly cortical, etiology of anorexia nervosa is reviewed. Topics covered are neuropsychiatric comorbidity, inheritance patterns, the neurobiology of body-image disturbance and of the eating function, perinatal and alcoholic insult to the brain, neurochemical and neuroelectric disturbance, anatomic and metabolic brain imaging, and neuropsychological impairment. It is concluded that there is indeed an important neuropsychological etiological dimension to anorexia nervosa. The profile most frequently associated with anorexia nervosa is right posterior hypometabolism, followed by right anterior hypermetabolism, both associated with right-sided abnormal electroencephalogram spiking. It is also proposed that bulimia consists of a "positive" neurological subtype and that restricting anorexia represents a "negative" neurological subtype. Priorities for further research into anorexia nervosa are specified to include twin adoption studies, brain electrical topography studies, postmortem histological studies, and experimentally inspired neuropsychological studies.

Cognition in eating disorders

Cognitive functions were investigated in four groups of women: 30 underweight anorexics, 38 normal-weight bulimics, 20 long-term weight-restored anorexics, and 39 normal controls. A MANOVA was used to examine performance on five neuropsychological domains derived from prior principal components analyses of a comprehensive neuropsychological battery. Underweight anorexics performed more poorly than normal controls in four of five neuropsychological domains (focusing/execution, verbal, memory, and visuospatial), while normal-weight bulimics showed poorer performances only in focusing/execution. The absolute differences in scores between eating disorder groups and normal controls were for the most part small, suggesting subtle rather than frank cognitive difficulties. Poorer neuropsychological test performance was associated with anxiety but not depression as measured by the Tryon, Stein, and Chu Tension scale and scale 2 of the MMPI respectively. The findings support previous reports of attentional difficulties in eating disorders but do not support the hypothesis of differential right-hemisphere dysfunction in eating disorders.

Inhibiting noradrenergic overactivity by inhibition of thromboxane and concomitant activation of opiate receptors via dietary means

A yin-yang hypothesis is presented linking noradrenergic activity, thromboxane, melatonin, left hemisphere functioning, and cyclic AMP on the one hand, and dopamine, beta-endorphin, calcium, right hemisphere functioning, and cyclic GMP on the other. It is further suggested that there is a yoking of NA, TXA2, serotonin and melatonin in the left hemisphere, and a similar yoking of DA, BE, calcium and cGMP in the right. Evidence is presented to support the hypothesis that each element (NA, TXA2, etc.) on one side can modulate or balance a corresponding element (DA, BE, etc.) on the other. It is suggested that thromboxane is the key element in noradrenergic overactivity and that not taking this into consideration has confounded much prior research. This theory takes into account information processing models as well as pharmacological data and neurochemical theory on coupling of adenylate cyclase to its hormone receptors. Inhibiting noradrenergic overactivity can be obtained by inhibiting thromboxane and concomitantly activating opiate receptors. This protocol may have clinical utility in treating a wide range of disorders such as: anxiety, depression, schizophrenia, sleeplessness, withdrawal states, enuresis, Gilles de la Tourette syndrome, Parkinsonism, Alzheimers, dementia, anorexia, infant ruminations, essential tremor, spasticity of spinal cord injury, diarrhoea, ulcerative colitis, extrapyramidal symptoms, akathisia, neuroleptic malignant syndrome, attention deficit disorder, hyperhidrosis, and possibly AIDS.

Brain morphology and regional cerebral blood flow in anorexia nervosa

Cranial computed tomography (CT) was performed in 12 patients with anorexia nervosa, revealing that the majority of the patients displayed ventricular dilatation and/or sulcal widening. In addition, regional cerebral blood flow (rCBF) was measured at admission and once again after weight gain, using xenon-133 dynamic single-photon emission tomography (dSPECT). The mean flow rates assessed at the first examination did not significantly differ from those assessed at the second examination and from those of a control group. There was a significant inverse relationship between the size of the cerebrospinal fluid spaces and the cerebral blood flow in the anorectics; a decrease in ventricular size after weight gain was associated with an increase in cerebral blood flow in this area. This finding, however, has to be interpreted with caution, as partial volume effects render the flow rates ambiguous in brain areas, which, in addition to neuronal tissue, also include ventricular and sulcal structures.

Neuropsychological test performance of bulimic patients

Thirty subjects with DSM-III diagnoses of bulimia were compared to 30 matched controls on the Luria-Nebraska Neuropsychological Battery. The bulimics showed poorer performance on tasks associated with functioning of the right frontal cortical area, primarily tasks involving speed of drawing geometric figures. The similarities of the findings to previous findings with anorexic samples and patients with affective disorders are discussed.