Altered norepinephrine metabolism following long-term weight recovery in patients with anorexia nervosa

Adaptive learning from outcome contingencies in eating-disorder risk groups

Eating disorders are characterised by altered eating patterns alongside overvaluation of body weight or shape, and have relatively low rates of successful treatment and recovery. Notably, cognitive inflexibility has been implicated in both the development and maintenance of eating disorders, and understanding the reasons for this inflexibility might indicate avenues for treatment development. We therefore investigate one potential cause of this inflexibility: an inability to adjust learning when outcome contingencies change. We recruited (n = 82) three groups of participants: those who had recovered from anorexia nervosa (RA), those who had high levels of eating disorder symptoms but no formal diagnosis (EA), and control participants (HC). They performed a reinforcement learning task (alongside eye-tracking) in which the volatility of wins and losses was independently manipulated. We predicted that both the RA and EA groups would adjust their learning rates less than the control participants. Unexpectedly, the RA group showed elevated adjustment of learning rates for both win and loss outcomes compared to control participants. The RA group also showed increased pupil dilation to stable wins and reduced pupil dilation to stable losses. Their learning rate adjustment was associated with the difference between their pupil dilation to volatile vs. stable wins. In conclusion, we find evidence that learning rate adjustment is unexpectedly higher in those who have recovered from anorexia nervosa, indicating that the relationship between eating disorders and cognitive inflexibility may be complex. Given our findings, investigation of noradrenergic agents may be valuable in the field of eating disorders.

Arterial stiffness in underweight and weight-restored anorexia nervosa

Cardiovascular complications have been demonstrated in patients with anorexia nervosa (AN) in both the state of starvation and during weight restoration, however, the underlying mechanisms remain unclear. The current study aimed to assess arterial stiffness via carotid-femoral pulse wave velocity (cfPWV) in the acute and weight-restored states of AN. The study also aimed to determine the association between psychological distress and cfPWV. The sample included 37 participants; 10 participants with AN, 17 who were weight-restored (AN-WR; minimum body mass index >18.5 for at least 12 months) and 10 healthy controls (HCs). cfPWV via applanation tonometry was conducted to assess arterial stiffness. Psychological distress was assessed using the depression anxiety stress scale (DASS-21) and the state-trait anxiety inventory (STAI). Between-group comparisons were performed to determine differences between groups, a two-stage hierarchical regression model was performed to determine the contribution of physiological and psychological variables on cfPWV and correlation analyses were also performed. Vascular stiffness was significantly increased in the AN and AN-WR groups, relative to HCs. The total DASS score was the only significant predictor of cfPWV across the sample. There were positive associations between cfPWV and depression, anxiety and stress, as assessed by the DASS. Furthermore, cfPWV was positively associated with STAI trait anxiety. Arterial stiffness was increased in individuals in the acute and weight-restored states of AN, demonstrating early signs of the development of arteriosclerotic cardiovascular disease. Increased arterial stiffness was associated with increased psychological distress, which may be a contributing mechanism to the increased cardiovascular risk in AN.

Autonomic Nervous System Function in Anorexia Nervosa: A Systematic Review

Background: Autonomic nervous system (ANS) dysfunction has been suggested to contribute to the high prevalence of cardiovascular complications in individuals with anorexia nervosa (AN), yet has not been thoroughly investigated. The current review aimed to synthesize the evidence of basal ANS function in individuals with a current diagnosis of AN and those with a previous diagnosis who had achieved weight restoration, as compared to controls. Methods: A systematic review of nine databases was conducted and studies that were published in a peer-review journal, in English, that included at least one assessment of ANS function in individuals with a current or previous diagnosis of AN were selected. Forty-six studies were included with a total of 811 participants with a current diagnosis of AN and 123 participants with a previous diagnosis of AN. Results: ANS function was assessed through heart rate variability (n = 27), orthostatic challenge, blood pressure variability or baroreflex sensitivity (n = 11), adrenergic activity (n = 14), skin conductance level (n = 4), and pupillometry (n = 1). Individuals with AN demonstrated increased parasympathetic activity and decreased sympathetic activity, suggestive of autonomic dysregulation. Following weight restoration, autonomic function trended toward, or was equivalent to, control levels. Discussion: Autonomic dysregulation is indicated through a range of assessments in individuals with AN. Future investigations should utilize a variety of assessments together in order to conclusively establish the nature of autonomic dysfunction in AN, and following extended weight restoration. Moreover, investigation into the co-occurrence of ANS function and cardiovascular risk is required.

How extreme dieting becomes compulsive: A novel hypothesis for the role of anxiety in the development and maintenance of anorexia nervosa

The US National Institute of Mental Health's Research Domain Criteria (NIMH RDoC) advocates the study of features common to psychiatric conditions. This transdiagnostic approach has recently been adopted into the study of anorexia nervosa (AN), an illness that can be considered compulsive in nature. This has led to the development of an account of AN that identifies key roles for the heightened reinforcement of starvation, leading to its excessive repetition, and goal-directed system dysfunction. Considering models of illness in other compulsive disorders, we extend the existing account to explain the emergence of reinforcement and goal-directed system abnormalities in AN, proposing that anxiety is central to both processes. As such we emphasise the particular importance of the anxiolytic effects of starvation, over other reinforcing outcomes, in encouraging the continuation of starvation within a model that proposes a number of mechanisms by which anxiety operates in the development and maintenance of AN. We suggest the psychopathology of AN mediates the relationship between the anxiolytic effects of starvation and excessive repetition of starvation, and that compulsive starvation has reciprocal effects on its determinants. We thus account for the emergence of symptoms of AN other than compulsive starvation, and for the relationship between different features of the disorder. By extending and adapting an existing explanation of AN, we provide a richer aetiological model that invites new research questions and could inform novel approaches to prevention and treatment.

Cerebellar sub-divisions differ in exercise-induced plasticity of noradrenergic axons and in their association with resilience to activity-based anorexia

The vermis or "spinocerebellum" receives input from the spinal cord and motor cortex for controlling balance and locomotion, while the longitudinal hemisphere region or "cerebro-cerebellum" is interconnected with non-motor cortical regions, including the prefrontal cortex that underlies decision-making. Noradrenaline release in the cerebellum is known to be important for motor plasticity but less is known about plasticity of the cerebellar noradrenergic (NA) system, itself. We characterized plasticity of dopamine β-hydroxylase-immunoreactive NA fibers in the cerebellum of adolescent female rats that are evoked by voluntary wheel running, food restriction (FR) or by both, in combination. When 8 days of wheel access was combined with FR during the last 4 days, some responded with excessive exercise, choosing to run even during the hours of food access: this exacerbated weight loss beyond that due to FR alone. In the vermis, exercise, with or without FR, shortened the inter-varicosity intervals and increased varicosity density along NA fibers, while excessive exercise, due to FR, also shortened NA fibers. In contrast, the hemisphere required the FR-evoked excessive exercise to evoke shortened inter-varicosity intervals along NA fibers and this change was exhibited more strongly by rats that suppressed the FR-evoked excessive exercise, a behavior that minimized weight loss. Presuming that shortened inter-varicosity intervals translate to enhanced NA release and synthesis of norepinephrine, this enhancement in the cerebellar hemisphere may contribute towards protection of individuals from the life-threatening activity-based anorexia via relays with higher-order cortical areas that mediate the animal's decision to suppress the innate FR-evoked hyperactivity.

Pharmacological manipulations in animal models of anorexia and binge eating in relation to humans

Eating disorders, such as anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorders (BED), are described as abnormal eating habits that usually involve insufficient or excessive food intake. Animal models have been developed that provide insight into certain aspects of eating disorders. Several drugs have been found efficacious in these animal models and some of them have eventually proven useful in the treatment of eating disorders. This review will cover the role of monoaminergic neurotransmitters in eating disorders and their pharmacological manipulations in animal models and humans. Dopamine, 5-HT (serotonin) and noradrenaline in hypothalamic and striatal regions regulate food intake by affecting hunger and satiety and by affecting rewarding and motivational aspects of feeding. Reduced neurotransmission by dopamine, 5-HT and noradrenaline and compensatory changes, at least in dopamine D2 and 5-HT(2C/2A) receptors, have been related to the pathophysiology of AN in humans and animal models. Also, in disorders and animal models of BN and BED, monoaminergic neurotransmission is down-regulated but receptor level changes are different from those seen in AN. A hypofunctional dopamine system or overactive α2-adrenoceptors may contribute to an attenuated response to (palatable) food and result in hedonic binge eating. Evidence for the efficacy of monoaminergic treatments for AN is limited, while more support exists for the treatment of BN or BED with monoaminergic drugs.

Anorexia nervosa--a noradrenergic dysregulation hypothesis

Anorexia nervosa manifests a wide range of features which cannot fully be explained on the basis of socio-cultural pressures to be thin, nor by starvation, nor dehydration. Evidence is emerging of a significant neurobiological contribution to its aetiology. However there has to date been no explanation for its pathogenesis that integrates the previously identified genetic, neurobiological and socio-cultural contributing factors. In this paper we propose an empirically-based hypothesis that genetically determined noradrenergic dysregulation, interacting with epigenetic factors, leads to high levels of anxiety, impaired neuroplasticity and regional cerebral hypoperfusion. These, in combination, lead to insula dysfunction. The resulting impairment in insula homuncular representation explains the pathognomonic body image distortion. This distortion, combined with high levels of body-focused anxiety, gives rise to intense dieting, noradrenergic precursor depletion, and initial reduction in anxiety. The subsequent rebound exacerbation of anxiety leads to a vicious cycle of maintenance. Novel treatment implications based on this hypothesis are briefly considered.

Bone loss in anorexia nervosa: leptin, serotonin, and the sympathetic nervous system

Anorexia nervosa (AN), a disorder characterized by the refusal to sustain a healthy weight, has the highest mortality of any psychiatric disorder. This review presents a model of AN that ties together advances in our understanding of how leptin, serotonin, and hypogonadism are brought about in AN and how they influence bone mass. Serotonin (5-hydroxytryptamine) is a key regulator of satiety and mood. The primary disturbance in AN results from alterations in serotonin signaling. AN patients suffer from serotonergic hyperactivity of Htr1a-dependent pathways that causes dysphoric mood and promotes restrictive behavior. By limiting carbohydrate ingestion, anorexics decrease their serotonin levels. Reduced serotonergic signaling in turn suppresses appetite through Htr1a/2b, decreases dysphoric mood through Htr1a/2a, and activates the sympathetic nervous system (SNS) through Htr2c receptors in the ventromedial hypothalamus. Activation of the SNS decreases bone mass through β2-adrenergic signaling in osteoblasts. Additional topics reviewed here include osteoblastic feedback of metabolism in anorexia, mechanisms whereby dietary changes exacerbate bone loss, the role of caloric restriction and Sirt1 in bone metabolism, hypothalamic hypogonadism's effects on bone mass, and potential treatments.

Hormonal profile heterogeneity and short-term physical risk in restrictive anorexia nervosa

CONTEXT

The relevance of hormonal assessment in anorexia nervosa (AN) management is still unclear. The short-term physical risk during undernutrition period of the disease is partially predicted by anthropometric and electrolytic parameters.

OBJECTIVE

The objective of the study was to evaluate hormonal profiles in a large cohort of AN and their relationship with critical states.

DESIGN AND SETTING

This was an observational monocentric cross-sectional study performed in the endocrinological unit.

PATIENTS AND OTHER PARTICIPANTS

Participants included 210 young female subjects with restrictive-type AN and 42 female controls of comparable age.

MAIN OUTCOME MEASURES

The following hormonal parameters were measured: thyroid hormones, GH, IGF-I, cortisol, oestradiol, FSH, LH, SHBG, dehydroepiandrosterone sulfate, plasma metanephrines, and bone markers. Their relation with registered short-term evolution of AN subjects after hormonal assessment was evaluated.

RESULTS

Except for metanephrines and dehydroepiandrosterone sulfate, most of the hormonal abnormalities previously reported in AN were confirmed. The manifestation of these hormonal abnormalities started below different body mass index (BMI) levels, ranging between 17 and 15 kg/m(2), even though an important percentage of normal values for every parameter was still noticed for very low BMIs. All patients who developed critical states during the 3 months after the hormonal assessment presented with BMI less than 15 kg/m(2) and a very increased level of cortisol, GH, and increased values of metanephrines.

CONCLUSIONS

The hormonal response to undernutrition is heterogeneous in a large population with restrictive AN. In clinical practice, metanephrines, GH, and/or cortisol data could be used as important predictors for severe short-term outcome.

Genetic susceptibility to eating disorders: associated polymorphisms and pharmacogenetic suggestions

Anorexia nervosa (AN), bulimia nervosa (BN) and binge-eating disorder (BED) are characterized by abnormal eating behaviors often resulting in dramatic physical consequences for the patients. The etiology of eating disorders (EDs) is currently unknown; however, a strong genetic contribution is likely to be involved. To date, the majority of genetic studies have focused on candidate genes, and polymorphic variants of genes coding for substances likely to be involved in the etiopathogenesis of EDs have been assessed for association with AN, BN, BED and/or ED-related phenotypic traits. Results have been generally inconsistent and cannot be considered conclusive because of several methodological flaws and differences, such as small sample sizes, ethnic heterogeneity of studied populations, lack of statistical correction for multiple testing, adoption of different diagnostic criteria and population stratification. Although, at present, no convincing evidence for associations of candidate genes with EDs has been provided, the 5-HT2A receptor gene and the BDNF gene seem to be promising candidates for genetic influences on AN, since polymorphic variants of these genes have been found quite consistently, although not specifically, linked to AN restricting subtype in large sample studies. Moreover, pharmacogenetic investigations have suggested a possible role of some gene polymorphisms in predicting the response to treatment with selective serotonin reuptake inhibitors in BN, but results are still preliminary. The heterogeneity of ED phenotypes is believed to represent the most relevant variable responsible for contradictory and not conclusive results. Future studies should focus on more homogeneous subgroups, either relying on specific ED traits or identifying endophenotypes. This will be useful also for prevention and treatment of EDs.

Hormonal and psychological factors linked to the increased thermic effect of food in malnourished fasting anorexia nervosa

OBJECTIVES

In patients with anorexia nervosa (AN), weight gain is lower than that expected from the energy content of the meals. Thus we investigated the thermic effect of food (TEF) in relation to subjective feelings and plasma hormone levels in a group of AN patients.

METHODS

TEF, feelings (14 items), and plasma release of beta-endorphin, ACTH, cortisol, dopamine, and catecholamines were evaluated in 15 AN patients (body mass index, 13.6 +/- 1.2 kg.m(-2)) and in 15 healthy women after three gastric loads (0, 300, 700 kcal) infused by a nasogastric tube in a blind design.

RESULTS

In AN, the blind loads induced an energy-dependent increase in TEF (P < 0.001), which was higher than that observed in healthy women (P < 0.001). Only in AN, a load-dependent decline in the high basal plasma level of beta-endorphin (P < 0.01), an increase in plasma ACTH (P < 0.02) after the two caloric loads, and an increase in cortisol, norepinephrine, and dopamine levels after the 700-kcal load only (P < 0.05) were noted. A calorie-dependent (P < 0.001) increase in nausea, abdominal discomfort, and fear of being fat ratings and a decrease in liking to eat (P < 0.001) and body image were observed in AN patients (P < 0.05). TEF correlated with ratings on satiation, nausea, uncomfortable abdominal swelling, body image, and fear of being fat (for all, P < 0.01).

CONCLUSION

In AN women, blindly infused loads induced a dose-dependent increase in TEF, which correlated with the increase in plasma cortisol, ACTH, and catecholamines as in unpleasant sensations, fear of being fat, and anxiety as well as a decline in elevated basal beta-endorphin. These results could explain the difficulty for AN patients in gaining weight.

Hypothalamic neurotransmitters in relation to normal and disturbed eating patterns

An integrated hypothesis for explaining eating behavior must consider the organism as a whole, the multiple brain neurotransmitters and structures involved, and the diverse variables that have impact on the expression of the behavior. In this review, we will examine a variety of brain monoamines and neuropeptides, in terms of their impact on eating, and also relate these neurochemical systems to peripheral autonomic and endocrine functions. We will propose how these central and peripheral systems may interact under normal and generally stable conditions, as well as how they may help to maintain energy or nutritional homeostasis under stressful conditions, in particular, food deprivation.

The norepinephrine transporter in physiology and disease

The norepinephrine transporter (NET) terminates noradrenergic signalling by rapid re-uptake of neuronally released norepinephrine (NE) into presynaptic terminals. NET exerts a fine regulated control over NE-mediated behavioural and physiological effects including mood, depression, feeding behaviour, cognition, regulation of blood pressure and heart rate. NET is a target of several drugs which are therapeutically used in the treatment or diagnosis of disorders among which depression, attention-deficit hyperactivity disorder and feeding disturbances are the most common. Individual genetic variations in the gene encoding the human NET (hNET), located at chromosome 16q12.2, may contribute to the pathogenesis of those diseases. An increasing number of studies concerning the identification of single nucleotide polymorphisms in the hNET gene and their potential association with disease as well as the functional investigation of naturally occurring or induced amino acid variations in hNET have contributed to a better understanding of NET function, regulation and genetic contribution to disorders. This review will reflect the current knowledge in the field of NET from its initial discovery until now.

Antidepressants for anorexia nervosa

BACKGROUND

Anorexia Nervosa (AN) is an illness characterised by extreme concern about body weight and shape, severe self-imposed weight loss, and endocrine dysfunction. In spite of its high mortality, morbidity and chronicity, there are few intervention studies on the subject.

OBJECTIVES

The aim of this review was to evaluate the efficacy and acceptability of antidepressant drugs in the treatment of acute AN.

SEARCH STRATEGY

The strategy comprised of database searches of the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register, MEDLINE (1966 to April 28th, 2005), EMBASE (1980 to week 36, 2004), PsycINFO (1969 to August week 5, 2004), handsearching the International Journal of Eating Disorders and searching the reference lists of all papers selected. Personal letters were sent to researchers in the field requesting information on unpublished or in-progress trials.

SELECTION CRITERIA

All randomised controlled trials of antidepressant treatment for AN patients, as defined by the Diagnostic and Statistical Manual, fourth edition (DSM-IV) or similar international criteria, were selected.

DATA COLLECTION AND ANALYSIS

Quality ratings were made giving consideration to the strong relationship between allocation concealment and potential for bias in the results; studies meeting criteria A and B were included. Trials were excluded if non-completion rates were above 50%. The standardised mean difference and relative risk were used for continuous data and dichotomous data comparisons, respectively. Whenever possible, analyses were performed according to intention-to-treat principles. Heterogeneity was tested with the I-squared statistic. Weight change was the primary outcome. Secondary outcomes were severity of eating disorder, depression and anxiety symptoms, and global clinical state. Acceptability of treatment was evaluated by considering non-completion rates.

MAIN RESULTS

Only seven studies were included. Major methodological limitations such as small trial size and large confidence intervals decreased the power of the studies to detect differences between treatments, and meta-analysis of data was not possible for the majority of outcomes. Four placebo-controlled trials did not find evidence that antidepressants improved weight gain, eating disorder or associated psychopathology. Isolated findings, favouring amineptine and nortriptyline, emerged from the antidepressant versus antidepressant comparisons, but cannot be conceived as evidence of efficacy of a specific drug or class of antidepressant in light of the findings from the placebo comparisons. Non-completion rates were similar between the compared groups.

AUTHORS' CONCLUSIONS

A lack of quality information precludes us from drawing definite conclusions or recommendations on the use of antidepressants in acute AN. Future studies testing safer and more tolerable antidepressants in larger, well designed trials are needed to provide guidance for clinical practice.

Epistatic interaction between the monoamine oxidase A and serotonin transporter genes in anorexia nervosa

The serotonin (5-HT) and norepinephrine (NE) systems are likely involved in the aetiology of anorexia nervosa (AN) as sufferers are premorbidly anxious. Specifically, we hypothesize that genes encoding proteins, which clear 5-HT and NE from the synapse, are prime candidates for affecting susceptibility to AN. Supporting our hypothesis, we earlier showed that the NE transporter (NET) and monoamine oxidase A (MAOA) genes appear to contribute additively to increased risk of developing restricting AN (AN-R). With regard to the MAOA gene, a sequence variant that increases MAOA activity and has suggested association with the anxiety condition, panic disorder was preferentially transmitted from parents to affected children. Here we provide evidence in support of interaction between the MAOA and serotonin transporter (SERT) genes in 114 AN nuclear families (patient with AN plus biological parents). A SERT gene genotype with no apparent individual effect on risk and known to be associated with anxiety is preferentially transmitted to children with AN (chi2 trend=9.457, 1 df, P=0.0021) and AN-R alone (chi2 trend=7.477, 1 df, P=0.0063) when the 'more active' MAOA gene variant is also transmitted. The increased risk of developing the disorder is up to eight times greater than the risk imposed by the MAOA gene variant alone--an example of synergistic epistatic interaction. If independently replicated, our findings to date suggest that we may have identified three genes affecting susceptibility to AN, particularly AN-R: the MAOA, SERT, and NET genes.

Gene-gene interaction between the monoamine oxidase A gene and solute carrier family 6 (neurotransmitter transporter, noradrenalin) member 2 gene in anorexia nervosa (restrictive subtype)

We earlier found an association between anorexia nervosa (AN) restrictive subtype (AN-R) and an inserted sequence within the NETpPR, a polymorphic region located in the promoter of the solute carrier family 6 (neurotransmitter transporter, noradrenalin) member 2 (SLC6A2) gene. To further examine the noradrenergic system in AN-R we performed an association study with a functional polymorphism (MAOA-uVNTR) in the promoter of the monoamine oxidase A (MAOA) gene. Since monoamine oxidase A metabolises noradrenalin, a positive association with the MAOA gene would be biologically plausible. The transmission disequilibrium test and 95 trios/duos (AN-R females+biological parents) showed the main effect of the longer, more transcriptionally active form of the MAOA-uVNTR (MAOA-L) to be statistically non-significant (McNemar's chi(2)=1.4, df=1, P=0.238, odds ratio: 1.4, 95% CI 0.8-2.7). A case-control approach supported this finding. We then stratified the MAOA-uVNTR TDT data according to the (a) NETpPR genotype of the AN-R females, and (b) NETpPR allele transmitted from NETpPR-S4/L4 heterozygous mothers. In both cases, contingency table analysis revealed previously unreported gene-gene interaction between the MAOA and SLC6A2 genes (P=0.019 and 0.019, respectively). Receiving an MAOA-L allele more than doubles the risk for developing AN-R, conditional on an individual also being a NETpPR-L4 homozygote (stratum-specific odds ratio: 2.4, 95% CI 1.1-6.0). These results suggest important involvement of the noradrenergic system in the biological underpinnings of AN-R.

Investigation of epistasis between the serotonin transporter and norepinephrine transporter genes in anorexia nervosa

Weight-restored patients with anorexia nervosa (AN) respond favorably to the selective serotonin reuptake inhibitor fluoxetine, which justifies association studies of the serotonin transporter gene (SLC6A4, alias SERT) and AN. Case-control studies suggest that the least transcriptionally active allele of the SERT gene promoter polymorphism (5-HTTLPR) has an increased frequency in AN patients. However, this finding was not replicated with 55 trios (AN child+parents) and the transmission disequilibrium test (TDT). To clarify the role of the 5-HTTLPR in susceptibility to AN, we used the TDT and 106 Australian trios to provide 93% power to detect a genotypic relative risk (GRR) of 2.0. Our results were negative for this GRR (McNemar's chi(2)=0.01, df=1, p=0.921, odds ratio 1.0, 95% CI 0.7-1.5). Additionally, we found no association with AN females, AN subtype, age at onset, or minimum BMI. We then performed the first reported investigation of epistasis between the SERT gene and norepinephrine transporter gene (SLC6A2, alias NET) in AN, as an earlier study suggested that atypical AN responds to the dual serotonin-norepinephrine reuptake inhibitor venlafaxine. We observed no epistasis between the 5-HTTLPR and a polymorphism within the NET gene promoter polymorphic region (NETpPR) (chi(2)=0.48, df=1, p=0.490). Although 5-HTTLPR modulates serotonin reuptake by the serotonin transporter, our analyses provide no evidence that susceptibility to AN is modified by 5-HTTLPR alone, nor in concert with as yet undetermined functional effects of the NETpPR polymorphism.

Anorexia nervosa (restrictive subtype) is associated with a polymorphism in the novel norepinephrine transporter gene promoter polymorphic region

Long-term weight-restored patients with anorexia nervosa (AN) have lower norepinephrine levels than controls. Since this may reflect altered reuptake by the norepinephrine transporter (NET), we hypothesised that the NET gene was involved in the genetic component of AN. PCR-amplification of an AAGG repeat island (AAGG1) in the NET gene promoter region revealed a novel 343-bp sequence with five additional AAGG repeat islands (AAGG2-AAGG6). We named the sequence from AAGG1 to AAGG6 inclusive, the NET gene promoter polymorphic region (NETpPR). A 4-bp deletion (S4) or insertion (L4) in AAGG4 resulted in the net loss or gain, respectively, of a putative Elk-1 transcription factor site. The transmission disequilibrium test(TDT) with 87 Australian trios (patient plus parents) demonstrated significant preferential transmission of L4 (McNemar's chi(2) = 7.806, df = 1, P = 0.0052, odds ratio: 2.1) from parent to child with restricting AN (AN-R), suggesting that L4 or a DNA variant in linkage disequilibrium with it, doubles the risk for developing AN-R.

Reward deficiency syndrome: a biogenetic model for the diagnosis and treatment of impulsive, addictive, and compulsive behaviors

The dopaminergic system, and in particular the dopamine D2 receptor, has been implicated in reward mechanisms. The net effect of neurotransmitter interaction at the mesolimbic brain region induces "reward" when dopamine (DA) is released from the neuron at the nucleus accumbens and interacts with a dopamine D2 receptor. "The reward cascade" involves the release of serotonin, which in turn at the hypothalmus stimulates enkephalin, which in turn inhibits GABA at the substania nigra, which in turn fine tunes the amount of DA released at the nucleus accumbens or "reward site." It is well known that under normal conditions in the reward site DA works to maintain our normal drives. In fact, DA has become to be known as the "pleasure molecule" and/or the "antistress molecule." When DA is released into the synapse, it stimulates a number a DA receptors (D1-D5) which results in increased feelings of well-being and stress reduction. A consensus of the literature suggests that when there is a dysfunction in the brain reward cascade, which could be caused by certain genetic variants (polygenic), especially in the DA system causing a hypodopaminergic trait, the brain of that person requires a DA fix to feel good. This trait leads to multiple drug-seeking behavior. This is so because alcohol, cocaine, heroin, marijuana, nicotine, and glucose all cause activation and neuronal release of brain DA, which could heal the abnormal cravings. Certainly after ten years of study we could say with confidence that carriers of the DAD2 receptor A1 allele have compromised D2 receptors. Therefore lack of D2 receptors causes individuals to have a high risk for multiple addictive, impulsive and compulsive behavioral propensities, such as severe alcoholism, cocaine, heroin, marijuana and nicotine use, glucose bingeing, pathological gambling, sex addiction, ADHD, Tourette's Syndrome, autism, chronic violence, posttraumatic stress disorder, schizoid/avoidant cluster, conduct disorder and antisocial behavior. In order to explain the breakdown of the reward cascade due to both multiple genes and environmental stimuli (pleiotropism) and resultant aberrant behaviors, Blum united this hypodopaminergic trait under the rubric of a reward deficiency syndrome.

Circadian neuroendocrine functions in disorders of eating behavior

Eating behavior is a complex function determined by regulatory mechanisms characterized by bioperiodic fluctuations. It involves the hypothalamus as well as the related higher centers in the central nervous system (CNS). Many hormones, neurotransmitters and neuropeptides play an important role in the synchronization of food intake. Our study therefore sets out to evaluate the circadian rhythms of several endocrine functions in women with eating disorders, to clarify the pathophysiology of the limbic-hypothalamic system. We measured the circadian rhythms of plasma melatonin, serum cortisol, growth hormone (GH) and prolactin (PRL) in 26 patients with anorexia nervosa (AN), 27 with primary obesity (OB) and 7 with bulimia nervosa (BN). Simultaneous evaluation of different neuroendocrine rhythms in these three groups revealed similar circadian abnormalities, (namely daytime persistence of melatonin secretion in AN and OB, and similar cortisol profile changes in AN and BN), together with evidence of internal desynchronization among the different bioperiodic functions. These findings suggest that some changes of the central pathways involved in the control of eating, mood and endocrine functions are common to dissimilar kinds of eating disorders.

Medications in the treatment of eating disorders

Effective planning for medication treatment in patients with bulimia nervosa and anorexia nervosa is based on a comprehensive clinical assessment, including a careful review of comorbid psychiatric disorders and response to treatments for previous episodes of the disorder. Although most patients with bulimia nervosa are offered a trial of psychotherapy, significant results of controlled trials have contributed to an increased role for medications in the treatment of patients with this disorder. Pharmacologic treatment of anorexia nervosa has similarities to that of treatment-resistant depression, with the clinician turning to open trials and clinical reports for clues to rational management. As described in this article, considerations of potential side effects and medical complications are likely to play an important role in guiding the choice of medication used for treatment of patients with eating disorders.

Central and peripheral noradrenalin regulation in eating disorders

Norepinephrine and its metabolites were studied in various body fluids (plasma, urine and cerebrospinal fluid) of patients with anorexia nervosa, bulimia nervosa and healthy young women. The reaction of plasma norepinephrine to different stimuli like orthostatic challenge, test meals, standardized exercise, mental challenge tests etc. were studied. All results indicate a reduced noradrenergic activity in the central and peripheral nervous system of patients with eating disorders. The clinical consequences of these changes are hypotension, bradicardia, hypothermia and depression. Evidence is presented that the reduced activity of the sympathetic nervous system is caused by starvation (anorexia nervosa) or intermittent dieting (bulimia nervosa).

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.

Effects of exercise on immune functions of undernourished mice

Regular moderate exercise may modulate the response to a stressor and thus improve immune functions in conditions commonly associated with immunodepression and elevated levels of stress hormones. For example, anorexia nervosa patients, many of whom engage in regular aerobic exercise, generally have normal immune function and viral disease resistance in spite of their severe undernutrition. To test the hypothesis that exercise can prevent undernutrition-induced immunodepression, mice were fed a nutritionally complete, semi-purified diet, either ad libitum or in restricted quantities to induce 25% loss of initial weight over 3 weeks. Half the animals from each dietary group were run on a treadmill for 30 min/day, 5 days/week. Exercise had no effect on several measures of nutritional status. Spleen weight and blastogenic response to lipopolysaccharide were significantly increased by exercise in undernourished mice. In vivo antibody response to sheep red blood cells, and in vitro splenic responses to concanavalin A and phytohemagglutin were not significantly affected by exercise. Serum corticosterone level was increased by food restriction and significantly decreased by exercise in the undernourished mice. Within a treatment group there were no significant correlations between serum corticosterone level and any immune system measure. Hypothalamic concentration of uric acid was increased in food restriction groups and concentration of norepinephrine was increased in exercise groups. The results suggest that regular exercise may help prevent undernutrition-induced immunodepression, possibly through modulation of the stress response.

Peripheral opioid secretory pattern in anorexia nervosa

The peripheral secretion of endogenous opioids was studied in 10 women with restrictive anorexia nervosa and 10 age- and sex-matched healthy controls. The circadian rhythm of beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH), and their responses to the administration of corticotropin releasing hormone (CRH, 1 micrograms/kg body weight, i.v.), clonidine (150 microgram, i.v.), domperidone (10 mg, i.v.), and 5-hydroxytryptophan (5-HTP, 200 mg, p.o.) were examined in patients and controls. The results revealed increased nocturnal secretion of beta-EP and diurnal-nocturnal secretion of beta-LPH with loss of circadian rhythmicity of both peptides, normal response to CRH stimulation, blunted response to clonidine and domperidine, and normal beta-EP and blunted beta-LPH response to 5-HTP stimulation. The data suggest a complex alteration of peripheral opioids and of central aminergic mechanisms that regulate proopiomelanocortin-derived peptide secretion and eating behavior.

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.

Hormonal circadian rhythms in eating disorders

The circadian rhythm of several plasma hormones (prolactin, growth hormone, adrenocorticotropic hormone (ACTH), cortisol, and melatonin) was simultaneously evaluated in 23 women with anorexia nervosa (AN), in 27 obese (OB) women, and in gender and age-matched healthy controls. A trend toward similar alterations of the circadian pattern of the different hormones was observed in the two groups of patients, with the exception of plasma growth hormone (GH), which exhibited nutrition-dependent impairments. The timing of the peaks for each hormonal rhythm revealed the existence of an internal desynchronization in both eating disorders.

Tyrosine hydroxylase, tryptophan hydroxylase, biopterin, and neopterin in the brain of anorexia nervosa

The activities of tyrosine hydroxylase and tryptophan hydroxylase and contents of biopterin and neopterin were measured for the first time in various regions of human brain from a patient with anorexia nervosa (AN). In AN as compared with controls, tyrosine hydroxylase activity was markedly reduced in all brain regions analyzed, while tryptophan hydroxylase activity and biopterin content had a tendency to increase. Neopterin content did not change dramatically. The opposite changes of tyrosine hydroxylase and tryptophan hydroxylase suggest an imbalance between the activity of catecholaminergic neurons and that of serotonergic neurons, and may be related to pathogenesis of AN.

Current perspectives on the eating disorders: I. History, psychological and biological aspects

An ongoing, major effort in psychiatry throughout the 1980s has been the study of anorexia and bulimia. In spite of ample effort on the part of researchers and clinicians, the etiology of these disorders remains elusive. Because of the multiple biological, sociocultural, and psychological forces involved and the early genesis of the disorder, an understanding of the eating disorders is tantamount to an appreciation of the developmental process itself. Part I of this paper presents a historical view of the eating disorders and reviews recent progress in classification criteria, epidemiology, biology, psychology, developmental, and analytic theory. Part II will focus on treatment, outcome, and research priorities.

Abnormalities in the response of plasma arginine vasopressin during hypertonic saline infusion in patients with eating disorders

We examined the response of plasma arginine vasopressin (pAVP) to intravenous 5% hypertonic saline in patients with anorexia nervosa (AN) and bulimia nervosa (BN). Patients did not differ from controls in their subjective response for the onset of thirst; however, only 5 patients (3 AN and 2 BN) showed pAVP levels that were within the normal range (0.5-11.0 pg/ml) for this test. With the exception of two eating disorder (ED) patients, all others showed some nonlinear irregularities in the pattern of their secretion of pAVP in response to the hypertonic saline infusion. Seven of the ED patients showed an irregular abnormally high pAVP secretion, and three patients showed abnormally low pAVP responses. Both of these pAVP secretion abnormalities occurred in underweight and weight-recovered AN patients, as well as in BN patients. The cause and pathophysiological consequences of these abnormalities remain unresolved.

Mood and orthostatic norepinephrine response in anorexia nervosa

The relationship between mood and noradrenergic activity, measured by orthostatic norepinephrine response (delta NE), was investigated in 24 patients with anorexia nervosa during inpatient treatment. Mood and delta NE correlated significantly at four out of five measurement points. Group comparisons identified significantly worse mood in patients with pathologically low delta NE values. Thus, biological consequences of altered eating behavior may also affect such psychological symptoms as depressed mood.

Melatonin circadian rhythm in anorexia nervosa and obesity

The mean 24-hour secretion and circadian rhythm of melatonin were studied in 12 female subjects with anorexia nervosa (AN), 13 massively obese (OB) women, and 9 normal weight healthy volunteers to investigate the relationship between type of feeding behavior and hormonal secretory pattern. Blood samples for melatonin were drawn every 4 hours from 0400 h to 2400 h and every 2 hours from 2400 h to 0400 h. Mean 24-hour melatonin secretion was significantly higher in AN than in OB patients and controls. Melatonin circadian rhythms were disrupted in 8 of the 12 AN patients and in 9 of the 13 OB subjects, with phase-advanced nocturnal rises, abnormal diurnal peaks, or no nocturnal rises. The population mean cosinor analysis validated the existence of a significant circadian rhythm of the hormone in AN but not in OB subjects. No significant correlation between mean 24-hour secretion or type of circadian alterations and degree of weight deficit or excess was observed. The circadian alterations of melatonin in AN and OB may be linked to impaired secretory tonus of noradrenalin in the central nervous system, possibly unrelated to feeding patterns.

Major affective disorder in anorexia nervosa and bulimia. A descriptive diagnostic study

DSM-III lifetime diagnoses were assessed in 52 patients with a lifetime history of anorexia nervosa or bulimia by means of a standardised diagnostic interview. It was found that 44.2% had a lifetime diagnosis of DSM-III major affective disorder, with abstaining anorectics having a lower rate of depression than those with bulimic symptoms. In the great majority of cases, the onset of affective disorder post-dated the onset of the eating disorder by at least one year. In patients whose eating disorder was in remission, the rate of depressive symptoms was lower than in those in the acute stage of their illness. These findings, combined with recent studies on biological changes in eating disorders, and psychological theories of depression, suggest that in most cases in which the two conditions are associated, the depression is secondary to the eating disorder.

Psychobiology of anorexia nervosa

The psychobiology of anorexia nervosa is described and explained under four headings; (1) the psychopathology as related to the motivation for fasting; (2) metabolic and somatic consequences of starvation, including brain morphology; (3) endocrine abnormalities in the hypothalamic-pituitary-adrenal and gonadal axis; and (4) the hunger drive and its possible perversions in terms of aspects of neuroethology and the reward system in the brain.

Relationship of clinical factors to caloric requirements in subtypes of eating disorders

Caloric requirements for weight gain in subgroups of anorectic patients (anorectic restrictors, anorectic binge-purgers) and weight maintenance in subgroups of anorectic and bulimic patients (bulimics with and without a prior history of anorexia nervosa) were studied in a total of 36 patients. No significant differences were found between subgroups of anorectic patients either in calories to gain weight or to maintain a normal weight. Bulimic patients, as a group, were found to require significantly fewer [corrected] calories than the group of anorectic patients to maintain a normal weight. Bulimic patients with a prior history of anorexia nervosa were found to require more calories for weight maintenance than bulimics with no such prior history. In the entire eating disorder population, there was a significant negative correlation between highest premorbid body mass index (BMI) and calories required to maintain weight. These findings suggest that differences in energy metabolism may be present in the eating disorder subgroups.

A placebo-controlled crossover study of oral clonidine in acute anorexia nervosa

The alpha 2-adrenergic agonist clonidine has been reported to increase feeding in several species. This study evaluated the effects of clonidine (500-700 micrograms/day), administered per os, to four treatment-resistant anorexia nervosa patients in a long-term placebo-controlled crossover trial. All patients increased their body weight significantly. Clonidine administration, however, did not influence the rate of weight gain, nor did clonidine affect hunger or satiety sensations. Similarly, 24-hour urinary 3-methoxy-4-hydroxyphenylglycol levels and levels of anxiety and depression were unchanged by clonidine. By contrast, clonidine showed significant hemodynamic effects; clonidine lowered systolic and diastolic blood pressure, reduced pulse rate, and produced sedation. Discontinuation of clonidine was associated with a small but significant weight loss compared to a small weight increase during the initiation of clonidine treatment. The results suggest that clonidine may not be indicated in the treatment of anorexia nervosa.

Beta 2-adrenergic receptor regulation in circulating mononuclear leukocytes in anorexia nervosa and bulimia

Mononuclear leukocyte (MNL) beta 2-adrenergic receptors and their coupled adenylate cyclase system were studied in underweight anorectics (n = 12), weight-recovered anorectics (n = 8), bulimics (n = 8), and age- and sex-matched controls (n = 39). Compared with controls, underweight anorectics had significantly fewer MNL beta 2-adrenergic receptor sites (Bmax) but did not differ in binding affinity (Kd). Weight-recovered anorectics and bulimics did not differ from controls on either Bmax or Kd. Compared with controls, all three patient groups had significantly reduced plasma levels of triiodothyronine (T3), while only underweight anorectics had significantly elevated plasma levels of cortisol. Plasma norepinephrine (NE) response to orthostasis was significantly lower in the three patient groups than in controls. The reduction in beta 2-adrenergic receptor number in underweight anorectics could reflect their elevated cortisol and reduced T3 levels. The decrease in beta 2-adrenergic receptor sites, together with the lower NE response to orthostasis, could be responsible for the reduced sympathetic activity of underweight anorectics.