The 5HTTLPR polymorphism, psychopathologic symptoms, and platelet [3H-] paroxetine binding in bulimic syndromes

Separating the Signal from the Noise: How Psychiatric Diagnoses Can Help Discern Food Addiction from Dietary Restraint

Converging evidence from both animal and human studies have implicated hedonic eating as a driver of both binge eating and obesity. The construct of food addiction has been used to capture pathological eating across clinical and non-clinical populations. There is an ongoing debate regarding the value of a food addiction "diagnosis" among those with eating disorders such as anorexia nervosa binge/purge-type, bulimia nervosa, and binge eating disorder. Much of the food addiction research in eating disorder populations has failed to account for dietary restraint, which can increase addiction-like eating behaviors and may even lead to false positives. Some have argued that the concept of food addiction does more harm than good by encouraging restrictive approaches to eating. Others have shown that a better understanding of the food addiction model can reduce stigma associated with obesity. What is lacking in the literature is a description of a more comprehensive approach to the assessment of food addiction. This should include consideration of dietary restraint, and the presence of symptoms of other psychiatric disorders (substance use, posttraumatic stress, depressive, anxiety, attention deficit hyperactivity) to guide treatments including nutrition interventions. The purpose of this review is to help clinicians identify the symptoms of food addiction (true positives, or "the signal") from the more classic eating pathology (true negatives, or "restraint") that can potentially elevate food addiction scores (false positives, or "the noise"). Three clinical vignettes are presented, designed to aid with the assessment process, case conceptualization, and treatment strategies. The review summarizes logical steps that clinicians can take to contextualize elevated food addiction scores, even when the use of validated research instruments is not practical.

Understanding the genetics and epigenetics of bulimia nervosa/bulimia spectrum disorder and comorbid borderline personality disorder (BN/BSD-BPD): a systematic review

PURPOSE

To evaluate and understand the genetic and epigenetic basis of bulimia nervosa/bulimia spectrum disorder and comorbid borderline personality disorder (BN/BSD-BPD).

METHODS

The present systematic review was conducted in accordance to PRISMA guidelines. Advanced systematic searches of Medline, EMBASE, PsychINFO, Web of Science, Scopus, CINHAL plus, and the Cochrane Library were conducted using the search terms 'bulimia nervosa', 'bulimia spectrum disorder', 'borderline personality disorder', 'genes', and 'genetics'. The search strategy garnered seven studies for inclusion in the present review.

RESULTS

Women with BN/BSD-BPD had significantly lower serotonin and monoamine oxidise activity compared to women with BN/BSD or healthy controls (HC). As well, women with BN/BSD-BPD displayed elevated methylation of the dopamine receptor gene promoter, brain-derived neurotrophic factor, and changes in the methylation of the glucocorticoid receptor gene promoter (NR3C1) compared to women with BN/BSD and HC. The results also demonstrated that rates of childhood sexual abuse and childhood physical abuse are higher in those with BN/BSD-BPD than those with BN/BSD and HC, and that these types of abuse are often correlated with the methylation differences seen in BN/BSD-BPD women.

CONCLUSION

Due to the differences observed between individuals with BN/BSD-BPD and those with BN/BSD and HC a genetic/epigenetic aetiological model of BN/BSD-BPD was developed and is proposed in this review. This evidence-based model visually illustrates the current state of the field and draws attention to the need for subsequent research.

A systematic review of blood-based serotonergic biomarkers in Bulimia Nervosa

Bulimia Nervosa (BN) is a serious eating disorder, which affects 0.8-2.9% of the young population. The etiology is unknown and biomarkers would support in understanding the pathophysiology of BN, and in identifying BN patients that may benefit from medical treatment. This systematic review aims to answer whether (a) BN deviate from healthy controls in terms of serotonin (5-HT) biomarkers in blood, and whether (b) blood-based 5-HT biomarkers could be used to tailor psychopharmacological treatment in BN. A literature search using PubMed, PsycINFO and Embase was done using the following search terms: "Bulimia Nervosa" AND "serotonin" AND "blood" OR "plasma" OR "serum". 32 studies were included in this systematic review. Several biomarkers and challenge tests were identified and all studies described an association with BN and dysregulation of the 5-HT system compared to healthy controls. Several studies pointed to an association also to borderline symptoms in BN. BN deviate from healthy controls in terms of 5-HT biomarkers in blood supporting an abnormal 5-HT system in BN. 5-HT biomarkers and associated methods could be used to tailor treatment in BN although as yet, most tests described are unpractical for bedside use.

Efficacy of intervention at traffic schools reducing impulsive action, and association with candidate gene variants

OBJECTIVE

Road traffic injuries are the leading cause of death among young people. Recognition of the contribution of impulsive behaviour may help novice drivers to behave more safely. Previously a brief intervention focusing on impulsive traffic behaviour conducted by psychologists in driving schools had been effective. The aim of this study was an independent re-evaluation of the effect of the intervention, as conducted by driving school teachers, and assessment of the potential associations with candidate genotypes.

METHODS

Driving school students (mean age 22.5, SD=7.9) were divided into intervention (n=704) and control (n=737) groups. Driving school teachers were trained to administer the intervention which consisted of a lecture and group work (1.5 h in total) on impulsivity. Traffic offences and crashes were monitored during 3 years, using police and traffic insurance fund databases. Functional polymorphisms of the dopamine transporter (DAT) and serotonin transporter genes (DAT1 VNTR and 5-HTTLPR) were assessed.

RESULTS

The intervention significantly lowered general traffic risk and prevalence of traffic accidents. DAT1 VNTR 9R carriers, particularly males, had higher general traffic risk in the whole sample. Female 5-HTTLPR s' allele carriers of the intervention group had the lowest general traffic risk. Intervention was most effective in female DAT1 VNTR 10R/10R homozygotes.

CONCLUSIONS

Brief impulsivity-centred intervention appears as a promising strategy for preventing risk-taking behaviour in novice drivers and can be fully integrated to driving school curriculum.

Role of eating disorders-related polymorphisms in obesity pathophysiology

Human biological system provides innumerable neuroendocrine inputs for food intake control, with effects on appetite's modulation and the satiety signs. Its regulation is very complex, engaging several molecular interactions with many tissues, hormones, and neural circuits. Thus, signaling molecules that control food intake are critical for normal energy homeostasis and a deregulation of these pathways can lead to eating disorders and obesity. In line of this, genetic factors have a significantly influence of the regulation of neural circuits controlling the appetite and satiety pathways, as well as the regulation of brain reward systems. Single Nucleotide Polymorphisms (SNPs) in genes related to hypothalamic appetite and satiety mechanisms, further in multiple neurotransmitter systems may contribute to the development of major Eating Disorders (EDs) related to obesity, among them Binge Eating Disorder (BED) and Bulimia Nervosa (BN), which are discussed in this review.

Risky driving and the persistent effect of a randomized intervention focusing on impulsivity: The role of the serotonin transporter promoter polymorphism

Road traffic accidents are a serious public health issue, and real-life traffic offences are an excellent indicator of the behavioural tendencies of impulsivity and risk-taking. We have previously reported on short-term efficacy of a brief intervention in driving schools to reduce traffic risks (Paaver et al., Accid. Anal. Prev., 2013; 50, 430-437), and have now addressed the question of whether does the impact of the intervention last for a few years, and whether traffic behaviour and the intervention effect are associated with the serotonin transporter polymorphism (5-HTTLPR) genotype as the central serotonin system is strongly associated with impulse control. Participants of the study were 1866 novice car-drivers (mean age 23.0, SD = 7.2 years). Data on traffic violations were obtained four years after intervention from the police database and on traffic collisions from the national traffic insurance database. DNA samples were available for 767 participants and 5-HTTLPR genotypes were classified using the triallelic model. For the observation period after the intervention, speeding, drunk driving and involvement in traffic accidents were significantly lower in the intervention group. 5-HTTLPR genotype was associated with traffic behaviour: The S'-allele carriers had significantly lower odds for speeding offences and traffic accidents. The lower prevalence of S'-allele carriers among those who had committed speeding offences was statistically significant in females, while the lower prevalence of having been involved in a traffic accident was rather observed in males. Statistically significant intervention effects were observed only in the L'/L' homozygotes who had higher prevalence of traffic incidents. Conclusively, the brief intervention in traffic schools had a significant impact on traffic safety within subsequent four years, and traffic behaviour was associated with the serotonin transporter genotype. These findings suggest that subjects who are less likely to self-regulate their driving habits while gaining experience would benefit from training of impulsivity recognition.

A systematic review and secondary data analysis of the interactions between the serotonin transporter 5-HTTLPR polymorphism and environmental and psychological factors in eating disorders

OBJECTIVES

To summarize and synthesize the growing gene x environment (GxE) research investigating the promoter region of the serotonin transporter gene (5-HTTLPR) in the eating disorders (ED) field, and overcome the common limitation of low sample size, by undertaking a systematic review followed by a secondary data meta-analysis of studies identified by the review.

METHOD

A systematic review of articles using PsycINFO, PubMed, and EMBASE was undertaken to identify studies investigating the interaction between 5-HTTLPR and an environmental or psychological factor, with an ED-related outcome variable. Seven studies were identified by the systematic review, with complete data sets of five community (n = 1750, 64.5% female) and two clinical (n = 426, 100% female) samples combined to perform four secondary-data analyses: 5-HTTLPR x Traumatic Life Events to predict ED status (n = 909), 5-HTTLPR x Sexual and Physical Abuse to predict bulimic symptoms (n = 1097), 5-HTTLPR x Depression to predict bulimic symptoms (n = 1256), and 5-HTTLPR x Impulsiveness to predict disordered eating (n = 1149).

RESULTS

Under a multiplicative model, the low function (s) allele of 5-HTTLPR interacted with traumatic life events and experiencing both sexual and physical abuse (but not only one) to predict increased likelihood of an ED and bulimic symptoms, respectively. However, under an additive model there was also an interaction between sexual and physical abuse considered independently and 5-HTTLPR, and no interaction with traumatic life events. No other GxE interactions were significant.

CONCLUSION

Early promising results should be followed-up with continued cross-institutional collaboration in order to achieve the large sample sizes necessary for genetic research.

Molecular Genetic Studies of Eating Disorders: Current Status and Future Directions

We review association studies that have examined the genetic basis of eating disorders. Overall, findings suggest that serotonin, brain-derived neurotrophic factor, and estrogen genes may be important for the development of the disorders. These neuronal systems influence behavioral and personality characteristics (e.g., anxiety, food intake) that are disrupted in eating disorders. Future studies would benefit from larger sample sizes and inclusion of behavioral and personality covariates in analyses. Consideration of the mechanisms of genetic effects and interactions between genes and environment is also needed to extend conceptualizations of the genetic basis of these disorders.

Mood instability underlies the relationship between impulsivity and internalizing psychopathology

Impulsivity, the tendency to act without adequate forethought, has been associated with various internalizing disorders. Mood instability, the tendency to experience rapid and intense mood swings, relates to both internalizing disorders and impulsivity. We hypothesized that the association between mood instability and impulsivity accounts for the relationship between impulsivity and internalizing psychopathology. We conducted two studies to test our hypothesis. In Study 1 we used data from the 2007 Adult Psychiatric Morbidity Survey to examine mood instability in the relationship between depression and impulsivity. Mood instability and impulsivity were assessed with the Structured Clinical Interview for DSM-IV Axis-II Personality Disorders and depression was assessed with the revised Clinical Interview Schedule. In Study 2 we used data from the 1984 and 1991 British Health and Lifestyle Surveys to examine mood instability in the longitudinal relationship between impulsivity and internalizing symptoms. Mood instability and impulsivity were measured with the Eysenck Personality Inventory and internalizing symptoms were assessed with the General Health Questionnaire. In both studies we used a sequential regression analysis to test our hypothesis. Results from Study 1 showed that participants with depression were more likely to report impulsivity, but this effect became nonsignificant when mood instability was included in the same regression model. In Study 2 impulsivity predicted internalizing symptoms seven years in the future, but this effect became nonsignificant after mood instability was included in the same regression model. We conclude that impulsivity relates to internalizing psychopathology largely by being associated with mood instability. Research and therapy for internalizing conditions might be more productively directed at mood instability rather than impulsivity.

Psychiatric co-morbidity in women presenting across the continuum of disordered eating

OBJECTIVE

To compare the prevalence and correlates of psychiatric co-morbidity across a large sample of college women without an eating disorder, those at high risk for an eating disorder and women diagnosed using DSM-5 criteria for an eating disorder.

PARTICIPANTS

549 college women aged 18-25.

METHODS

Data from the Eating Disorder Examination, the Structured Clinical Interview for DSM-IV Axis I disorders and self-report questionnaires were analyzed using logistic regression for categorical data and ANCOVA for continuous measures.

RESULTS

Eating disordered symptomatology was strongly associated with anxiety disorders, mood disorders and insomnia. These co-morbidities (type and severity) tend to increase with eating disorder symptom severity.

CONCLUSIONS

Prevention and treatment programs for eating disorders need to address the high levels of mood, anxiety and sleep problems in this population. The findings on insomnia are novel and suggest that sleep disturbance may play an integral role in eating-related difficulties.

[Role of Serotonin Transporter Gene in Eating Disorders]

BACKGROUND

The serotoninergic system has been implicated in mood and appetite regulation, and the serotonin transporter gene (SLC6A4) is a commonly studied candidate gene for eating disorders. However, most studies have focused on a single polymorphism (5-HTTLPR) in SLC6A4.

OBJECTIVE

We present the studies published on the association between eating disorders (ED) and 5-HTTLPR polymorphism in anorexia nervosa (AN), bulimia nervosa (BN), and eating disorders not otherwise specified (EDNOS).

METHOD

Search of databases: MEDLINE, ISI, and PubMed for SLC6A4 and ED.

CONCLUSIONS

From a review of 37 original articles, it was suggested that carriers of S allele is a risk factor for eating disorders, especially for AN. However, BN did not show any association. Also, BMI, impulsivity, anxiety, depression, and age of onset have been associated with S allele in ED patients.

Perplexities of treatment resistance in eating disorders

BACKGROUND

Treatment resistance is an omnipresent frustration in eating disorders. Attempts to identify the features of this resistance and subsequently develop novel treatments have had modest effects. This selective review examines treatment resistant features expressed in core eating disorder psychopathology, comorbidities and biological features. Novel treatments addressing resistance are discussed.

DESCRIPTION

The core eating disorder psychopathology of anorexia nervosa becomes a coping mechanism likely via vulnerable neurobiological features and conditioned learning to deal with life events. Thus it is reinforcing and ego syntonic resulting in resistance to treatment. The severity of core features such as preoccupations with body image, weight, eating and exercising predicts greater resistance to treatment. Bulimia nervosa patients are less resistant to treatment with treatment failure related to greater body image concerns, impulsivity, depression, severe diet restriction and poor social adjustment. For those with binge eating disorder overweight in childhood and high emotional eating predicts treatment resistance. There is suggestive data that a diagnosis of an anxiety disorder and severe perfectionism may confer treatment resistance in anorexia nervosa and substance use disorders or personality disorders with impulse control problems may produce resistance to treatment in bulimia nervosa. Traits such as perfectionism, cognitive inflexibility and negative affect with likely genetic influences may also affect treatment resistance. Pharmacotherapy and novel therapies have been developed to address treatment resistance. Atypical antipsychotic drugs have shown some effect in treatment resistant anorexia nervosa and topiramate and high doses of SSRIs are helpful for treatment of resistant binge eating disorder patients. There are insufficient randomized controlled trials to evaluate the novel psychotherapies which are primarily based on the core psychopathological features of the eating disorders.

CONCLUSION

Treatment resistance in eating disorders is usually predicted by the severity of the core eating disorder psychopathology which develops from an interaction between environmental risk factors with genetic traits and a vulnerable neurobiology. Future investigations of the biological features and neurocircuitry of the core eating disorders psychopathology and behaviors may provide information for more successful treatment interventions.

Epistatic interactions implicating dopaminergic genes in bulimia nervosa (BN): relationships to eating- and personality-related psychopathology

We explored the influence of interactions between polymorphisms acting upon postsynaptic receptors (DRD2 TaqA1 rs1800497 and DRD4 7R) and dopamine regulators (COMT rs4680 and DAT1) on the expression of eating symptoms and personality traits in women with bulimia-spectrum eating disorders. We had 269 bulimic women provide blood for genetic assays, and measured eating-disorder symptoms and psychopathological traits using structured interviews and self-report questionnaires. We observed two epistatic interactions on symptom indices: interactions (in predicted directions) of DRD2 by DAT were seen on Body Mass Index (p=.023), and of DRD4 by COMT on self-harming behaviors (p=.014)--with genetic effects that would correspond to reduced dopamine transmission coinciding with more-pathological scores. Our findings suggest that genes acting in the dopamine system interact to influence both eating-related and personality psychopathology, with the result that lower levels of dopamine neuro-transmission correspond to increased psychopathology and body mass in women with bulimia-spectrum disorders. We discuss the implications of our observations.

Current status of functional imaging in eating disorders

Eating Disorders are complex psychiatric problems that involve biologic and psychological factors. Brain imaging studies provide insights about how functionally connected brain networks may contribute to disturbed eating behavior, resulting in food refusal and altered body weight, but also body preoccupations and heightened anxiety. In this article, we review the current state of brain imaging in eating disorders, and how such techniques may help identify pathways that could be important in the treatment of those often detrimental disorders.

Bupropion versus sertraline in the treatment of depressive patients with binge eating disorder: retrospective cohort study

This study sought to compare Bupropion versus Sertraline in the treatment of depressed patients with Binge Eating Disorder (BED) prescribed off-label. Medical records of outpatients with diagnosis of BED and Depression (DSM-IV-TR criteria) were selected: 15 patients were treated with bupropion 150 mg/per day, and 15 with sertraline 200 mg/per day. During the screening and control visits (2°-6°-14°-24° week), the selected patients were first weighed and then evaluated using the following questionnaires: Binge Eating Disorder-Clinical Interview (BEDCI), Beck Depression Inventory (BDI), State-Trait Anxiety Inventory X (STAI-X) and Arizona Sexual Experience Scale (ASEX). Both drugs reduced anxious-depressive symptoms and binge frequency: Bupropion showed a better effectiveness in reducing weight and improving sexual performances; weight loss related to it was proportional to the body mass index. Bupropion may be associated with more weight loss in BED, depressed patients than sertraline.

Comorbidity of partial and subthreshold ptsd among men and women with eating disorders in the national comorbidity survey-replication study

OBJECTIVE

The comorbidity of posttraumatic stress disorder (PTSD) and eating disorders (EDs) is high among women but has been understudied in men. Little is known about the association between partial or subthreshold PTSD and EDs among women or men.

METHOD

This study included PTSD and ED data from male (n = 2,382) and female (n = 3,310) National Comorbidity Survey-Replication study participants.

RESULTS

The vast majority of women and men with anorexia nervosa, bulimia nervosa (BN), and binge eating disorder (BED) reported a history of interpersonal trauma. Rates of PTSD were significantly higher among women and men with BN and BED. Subthreshold PTSD was more prevalent than threshold PTSD among women with BN and women and men with BED.

DISCUSSION

Interpersonal forms of trauma, PTSD, and subthreshold/partial PTSD, were prevalent among men and women with EDs. Findings highlight the importance of assessing for trauma and PTSD in ED patients.

Serotonin transporter binding after recovery from bulimia nervosa

OBJECTIVE

Physiological and pharmacological studies indicate that altered brain serotonin (5-HT) activity could contribute to a susceptibility to develop appetitive and behavioral alterations that are characteristic of bulimia nervosa (BN).

METHOD

Eight individuals recovered from BN (REC BN) and eight healthy control women were scanned with [11C]DASB and positron emission tomography imaging of the 5-HT transporter (5-HTT). Logan graphical analysis was applied, and parametric binding potential (BP(nondisplaceable (ND)) ) images were generated. Voxel-by-voxel t-tests and a region of interest (ROI) analysis were conducted.

RESULTS

REC BN had significantly lower [11C]DASB BP(ND) in midbrain, superior and inferior cingulate and significantly higher [11C]DASB BP(ND) in anterior cingulate and superior temporal gyrus in the voxel-based analysis. ROI analysis indicated lower [11C]DASB BP(ND) in midbrain (p = .07), containing the dorsal raphe, in REC BN, consistent with our earlier studies.

DISCUSSION

These preliminary findings of a small-scale study confirm and extend previous data suggesting that ill and recovered BN have altered 5-HTT measures, which potentially contribute to BN symptomatology and/or differential responses to medication.

The impact of adverse life events and the serotonin transporter gene promoter polymorphism on the development of eating disorder symptoms

Adverse life events have been shown to predict weight fluctuations and dietary restraint, as well as eating disorders during adolescence or early adulthood. Since the s-allele carriers of the 5-HTT gene-linked polymorphic region (5-HTTLPR) are biologically more reactive to stress related stimuli, we aimed to explore whether the eating disturbances are predicted by environmental stressors and moderated by the 5-HTTLPR genotype. The sample was based on the younger cohort of the Estonian Children Personality, Behaviour and Health Study and included those participating in its second and third wave. The history of stressful life events was self-reported at age 15. Data on eating behaviour and attitudes, anxiety, impulsivity and depressiveness were collected at age 18. The effect of the adverse life events on binge eating and on drive for thinness was found to be moderated by the 5-HTTLPR. Adolescent girls who at age 15 had reported a history of frequent adverse life events had elevated scores in EDI-2 Bulimia subscale at age 18 if they were carrying the s-allele. The effect of the s-allele on binge eating was even more pronounced when solely the experience of sexual abuse was considered. The interaction effect of the 5-HTTLPR and the past sexual abuse was also observed on drive for thinness. These data give further support to the idea that adverse life events in childhood may heighten susceptibility to serotonergic dysregulation following stress, and suggest that in individuals vulnerable to eating disorders this may result in disturbed eating behaviours.

Developmental perspectives on vulnerability to nonsuicidal self-injury in youth

Nonsuicidal self-injury (NSSI) is defined as intentionally causing bodily harm to oneself without the intent to kill oneself. Recently, there has been an increase in research aimed at understanding why individuals, especially youth and young adults, engage in NSSI. This chapter explores the emergence and maintenance of NSSI from a developmental perspective. Epidemiological research suggests that rates of NSSI increase dramatically from early adolescence to young adulthood. No study has investigated NSSI in youth younger than age 10. Current understanding of how emotion and cognitions as well as interpersonal processes play a role in the emergence and maintenance of NSSI is explored. Further, the role of biology (e.g., neurological underpinnings, genetic associations, HPA-axis functioning) on NSSI is explored. Throughout the chapter, particular limitations (e.g., sample selection, measurement issues) in the extant corpus of knowledge are highlighted. Finally, we consider future research directions that may inform developmentally sensitive understanding of the proximal and distal risk factors that may affect the emergence and maintenance of NSSI across the life span.

5-HTTLPR moderates the relation between changes in depressive and bulimic symptoms in adolescent girls: a longitudinal study

OBJECTIVE

Depression and bulimia both are associated with low serotonin levels. We examined whether the serotonin transporter gene (5-HTTLPR) moderates the relation between depressive and bulimic symptoms over time.

METHOD

Fifty adolescent girls with no current or past Axis I disorder were genotyped for the 5-HTTLPR gene. Twice, 6 months apart, participants completed self-report measures of depressive symptoms and bulimic symptoms.

RESULTS

The association between change in depressive symptoms and change in bulimic symptoms over time was significantly stronger in girls who are homozygous for the short 5-HTTLPR allele than for girls with at least one long allele.

DISCUSSION

This finding is consistent with previous studies documenting a relation between depressive and bulimic symptoms in adolescents. Few studies, however, considered the possible role of serotonin linking both disorders. Gaining a better understanding of developmental effects of low serotonin could help to identify high-risk individuals and provide effective prevention and intervention.

The 5-HTTLPR polymorphism and eating disorders: a meta-analysis

OBJECTIVE

Eating disorders are influenced by both environmental factors and genes. The 5-HTTLPR polymorphism of serotonin transporter gene has been suggested as a good candidate. This meta-analysis was undertaken: (1) to investigate the association between 5-HTTLPR and eating disorders considered as a whole, including anorexia (AN), bulimia (BN), and binge eating disorder (BED); (2) to extend recently reported findings on the association between 5-HTTLPR and AN-BN.

METHOD

PubMed, ISI, and PsycINFO databases were searched for studies published until October 2009. Fifteen studies have been included. Data were analyzed with the Cochrane Collaboration Review Manager Software. Quality of studies and publication bias were assessed.

RESULTS

An association between S allele and eating disorders, in particular AN, has been found.

DISCUSSION

To be carrier of the 5-HTTLPR S allele seem to represent a risk factor for eating disorders, especially for AN. However, considering the reported high between-study heterogeneity, future studies should focus on more homogeneous endophenotype.

Platelet [³H] paroxetine binding in female patients with borderline personality disorder and their sisters

Paroxetine binding could be a vulnerability marker for traits associated with borderline personality disorder (BPD). To study this relationship, we examined [³H] paroxetine binding in female patients with BPD and their sisters. The sample consisted of 54 sibling pairs in which a proband met criteria for BPD. All subjects were given the Diagnostic Interview for Borderlines, revised (DIB-R), the Diagnostic Assessment for Personality Pathology: Brief Questionnaire (DAPP-BQ), the Barratt Impulsivity Scale (BIS), the Affective Lability Scale (ALS), the Hamilton Rating Scale for Anxiety (HAM-A), the Hamilton Rating Scale for Depression (HAM-D), and the Symptom Checklist-90, revised (SCL-90-R). All subjects had platelets assayed for [³H] paroxetine binding. There were no significant differences between probands and sisters, but both groups scored significantly lower than a previously studied control group on B(max). There were no differences on Kd. Neither B(max) nor K(d) was related to most trait or symptomatic measures. Paroxetine binding could reflect endophenotypes common to BPD probands and their first-degree relatives.

Molecular-genetic correlates of self-harming behaviors in eating-disordered women: findings from a combined Canadian-German sample

Across populations, findings suggest that rates of self-mutilation, suicidal acts, and other self-harming behaviors (SHBs) may be influenced by polymorphisms that code for activity of the serotonin transporter (e.g., 5HTTLPR) and the enzyme, monoamine oxidase A (e.g., MAOAuVNTR). SHBs being common in patients with Eating Disorders (EDs), we evaluated (in a large sample of eating-disordered women) relationships between triallelic 5HTTLPR and MAOAuVNTR variants, on the one hand, and SHBs, on the other. We had 399 eating-disordered women report on eating symptoms and lifetime history of SHBs, and provide blood samples for genotyping. Individuals carrying high-function MAOAuVNTR alleles reported a history of SHBs about twice as often as did carriers of low-function alleles. We obtained no comparable main effect of 5HTTLPR, or MAOAuVNTR×5HTTLPR interaction effect. Genetic variations did not predict severity of eating symptoms. As in other populations, our findings link the MAOAuVNTR high-function alleles with increased risk of self-directed harm in bulimic females. We discuss theoretical and clinical ramifications of our results.

Serotonin: imaging findings in eating disorders

Anorexia nervosa (AN) and bulimia nervosa (BN) are disorders characterized by aberrant patterns of feeding behavior, weight regulation, and disturbances in attitudes and perceptions toward body weight and shape. Several lines of evidence nominate disturbances of serotonin (5-HT) pathways as playing a role in the pathogenesis and pathophysiology of AN and BN. For example, 5-HT pathways are known to contribute to the modulation of a range of behaviors commonly seen in individuals with AN and BN. New technology using brain imaging with radioligands offers the potential for understanding previously inaccessible brain 5-HT neurotransmitter function and its dynamic relationship with human behaviors. Recent studies using positron emission tomography and single photon emission computed tomography with 5-HT-specific radioligands have consistently shown 5-HT(1A) and 5-HT(2A) receptor and 5-HT transporter alterations in AN and BN in cortical and limbic structures, which may be related to anxiety, behavioral inhibition, and body image distortions. These disturbances are present when subjects are ill and persist after recovery, suggesting that these may be traits that are independent of the state of the illness. Effective treatments for AN and BN have been elusive. A better understanding of neurobiology is likely to be important for developing specific and more powerful therapies for these often chronic and deadly disorders.

Tryptophan-hydroxylase 2 haplotype association with borderline personality disorder and aggression in a sample of patients with personality disorders and healthy controls

BACKGROUND

There is a decreased serotonergic function in impulsive aggression and borderline personality disorder (BPD), and genetic association studies suggest a role of serotonergic genes in impulsive aggression and BPD. Only one study has analyzed the association between the tryptophan-hydroxylase 2 (TPH2) gene and BPD. A TPH2 "risk" haplotype has been described that is associated with anxiety, depression and suicidal behavior.

METHODS

We assessed the relationship between the previously identified "risk" haplotype at the TPH2 locus and BPD diagnosis, impulsive aggression, affective lability, and suicidal/parasuicidal behaviors, in a well-characterized clinical sample of 103 healthy controls (HCs) and 251 patients with personality disorders (109 with BPD). A logistic regression including measures of depression, affective lability and aggression scores in predicting "risk" haplotype was conducted.

RESULTS

The prevalence of the "risk" haplotype was significantly higher in patients with BPD compared to HCs. Those with the "risk" haplotype have higher aggression and affect lability scores and more suicidal/parasuicidal behaviors than those without it. In the logistic regression model, affect lability was the only significant predictor and it correctly classified 83.1% of the subjects as "risk" or "non-risk" haplotype carriers.

CONCLUSIONS

We found an association between the previously described TPH2 "risk" haplotype and BPD diagnosis, affective lability, suicidal/parasuicidal behavior, and aggression scores.

The 5-HTTLPR polymorphism of the serotonin transporter gene and short term behavioral response to methylphenidate in children with ADHD

BACKGROUND

Animal models of ADHD suggest that the paradoxical calming effect of methylphenidate on motor activity could be mediated through its action on serotonin transmission. In this study, we have investigated the relationship between the 5-HTTLPR polymorphism in the serotonin transporter gene (SLC6A4) and the response of ADHD relevant behaviors with methylphenidate treatment.

METHODS

Patients between ages 6-12 (n = 157) were assessed with regard to their behavioral response to methylphenidate (0.5 mg/kg/day) using a 2-week prospective within-subject, placebo-controlled (crossover) trial. The children were then genotyped with regard to the triallelic 5-HTTLPR polymorphism in the SLC6A4 gene.

MAIN OUTCOME MEASURE

Conners' Global Index for parents (CGI-Parents) and teachers (CGI-Teachers) at baseline and at the end of each week of treatment with placebo and methylphenidate. For both outcome measurements, we used a mixed model analysis of variance to determine gene, treatment and gene x treatment interaction effects.

RESULTS

Mixed model analysis of variance revealed a gene x treatment interaction for CGI-Parents but not for CGI-Teachers. Children homozygous for the lower expressing alleles (s+lG = s') responded well to placebo and did not derive additional improvement with methylphenidate compared to children carrying a higher expressing allele (lA). No genotype main effects on either CGI-Parents or CGI-teachers were observed.

CONCLUSIONS

A double blind placebo-controlled design was used to assess the behavioral effects of methylphenidate in relation to the triallelic 5-HTTLPR polymorphism of the SLC6A4 gene in children with ADHD. This polymorphism appears to modulate the behavioral response to methylphenidate in children with ADHD as assessed in the home environment by parents. Further investigation is needed to assess the clinical implications of this finding.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00483106.

Effects of cognitive-behavioral therapy on Eating Disorders: neurotransmitter secretory response to treatment

The effects of cognitive-behavioral therapy (CBT) on central dopamine (DA), noradrenaline (NE) and serotonin (5-HT) secretion were studied in a group of 50 female inpatients, of which 14 suffered from anorexia nervosa restricted type (AN-R), 14 from anorexia nervosa bingeing-purging type (AN-BP), and 22 from bulimia nervosa (BN). The aim of the study was to see whether or not CBT modifies the secretion of central DA (blood homovanillic acid=HVA), NE (blood 3-methoxy-4-hydroxy-phenylglycol=MHPG) and the 5-HT transporter (as evaluated by the platelet paroxetine binding=[(3)H]-Par-binding), if the physical and psychological effects of CBT correlate with changes of the neurotransmitter secretion; and if the biological effects of CBT are linked to specific psychopathological aspect of the disorders. The treatment lasted 20 weeks. Body-mass Index, bingeing and purging, specific AN-BN psychopathological (EDE 12-OD), depression (Beck Inventory), anxiety (STAY Form-Y-1), impulsiveness (Barratt Impulsiveness Scale), self-esteem (Rosenberg Self-Biochemical Scale) and temperament (Temperament and Character Inventory, Cloninger Scale) were assessed at baseline and at the end of the treatment. CBT significantly improved the psychophysical aspects of the diseases. HVA and MHPG concentrations did not change. The [(3)H]-Par-binding parameters, the maximum binding capacity (B(max)) and dissociation constant (K(d)) values did not change in either AN-R or AN-BP patients, while the [(3)H]-Par B(max) (and not the K(d)) increased significantly in BN patients. Correlations emerged between basal and final [(3)H]-Par B(max) values and psychopathological scores, but not between CBT-induced differences between basal and final values. Our data suggest that only in BN CBT may act through changes in 5-HT system function.

Serotonin transporter gene promoter polymorphism affects the severity of binge eating in general population

OBJECTIVE

The s-allele of the 5-HTTLPR has been suggested to lead to the development of less efficient and less flexible 5-HT system and has been associated to different forms of psychopathology. It has also been shown that alterations in serotonergic activity contribute to the pathophysiology of binge eating but it is not clear which changes in 5-HT function observed in eating disorder patients represent trait vs state effect. We investigated the association between the 5-HTTLPR and binge eating in a population-representative sample of women, and tested whether the 5-HTTLPR genotype influences the severity of binge eating.

METHODS

The sample was based on women participating in the third wave of the Estonian Children Personality, Behaviour and Health Study. EDI-2 subscales - drive for thinness and bulimia - were used to assess eating behaviour and attitudes. Barratt Impulsiveness Scale (BIS-11) and State and Trait Anxiety Inventory (STAI) were used to measure impulsivity and anxiety. Participants were genotyped for the 5-HTTLPR.

RESULTS

There was no 5-HTTLPR genotype effect on binge eating even after the covarying effect of impulsivity and anxiety was controlled for. However, women prone to binge eating and carrying the s-allele showed significantly higher levels of bulimia scores, and among them, women with s/s genotype had also higher levels of state anxiety and tendency for higher impulsivity.

CONCLUSIONS

While the 5-HTTLPR genotype does not predict symptoms of eating disorder in general population, the s-allele, and especially the s/s genotype increases the risk for affective instability and symptom severity.

Neural circuits, neurotransmitters, and behavior: serotonin and temperament in bulimic syndromes

In bulimia nervosa (BN), and in related binge-purge syndromes, factors affecting central serotonin (5-hydroxytryptamine, 5-HT) function appear to contribute not only to appetitive dysregulation but also to temperamental and personality manifestations. Drawing upon findings from neurobiological, molecular-genetic, and brain-imaging studies, we present an integrative model of the role of 5-HT function in bulimic syndromes. At the core of our model is a consideration of the ways in which diverse hereditary and environmental influences impact the action of the 5-HT system. We believe that our model helps account for heterogeneous traits seen in the bulimic population, for disproportionate representation of individuals displaying pathological personality traits and exposure to severe environmental stressors, and for interindividual variations as to treatment response.

The possible influence of impulsivity and dietary restraint on associations between serotonin genes and binge eating

Although serotonin (5-HT) genes are thought to be involved in the etiology of bulimia nervosa and binge eating, findings from molecular genetic studies are inconclusive. This may be due to limitations of past research, such as a failure to consider the influence of quantitative traits and gene-environment interactions. The current study investigated these issues by examining whether quantitative traits (i.e., impulsivity) and environmental exposure factors (i.e., dietary restraint) moderate 5-HT gene/binge eating associations in a sample of young women (N = 344). Binge eating was assessed using the Minnesota Eating Behavior Survey and the Dutch Eating Behavior Questionnaire (DEBQ). Impulsivity was assessed with the Barratt Impulsiveness Scale-Version 11. Dietary restraint was measured with a factor score derived from common restraint scales. Saliva samples were genotyped for the 5-HT2a receptor T102C polymorphism and 5-HT transporter promoter polymorphism. As expected, impulsivity and dietary restraint were associated with binge eating. Although the T allele of the 5-HT2a receptor gene and the s allele of the 5-HTT gene were associated with higher levels of impulsivity, there were no main effects of 5-HT genotypes on any binge eating measure, and interactions between genotypes, impulsivity, and dietary restraint were non-significant. In conclusion, we found no evidence to suggest that dietary restraint or impulsivity moderate associations between binge eating and these 5-HT genes. Future research should continue to explore interaction effects by examining larger samples, assessing dietary intake directly, and investigating other genes, traits, and environmental factors that may be related to binge eating and bulimia nervosa.

Association of trait-defined, eating-disorder sub-phenotypes with (biallelic and triallelic) 5HTTLPR variations

CONTEXT

Efforts to classify eating-disordered individuals based on concurrent personality traits have consistently converged on a typology encompassing "over-regulated", "dysregulated", and "low psychopathology" subgroups. In various populations, evidence has associated personality variations of an "over-regulated/dysregulated" type with differences on serotonin-system indices, and specifically, with different loadings of serotonin transporter promoter regulatory region polymorphism (5HTTLPR) genotypes and alleles. We explored the extent to which an empirical, trait-defined typology of eating-disordered individuals coincided systematically with variations in 5HTTLPR, assayed using biallelic and triallelic models.

METHOD

We tested 185 women with a DSM-IV eating disorder (108 with Bulimia Nervosa, 17 Anorexia Nervosa, and 60 an Eating Disorder Not Otherwise Specified) and 93 with no eating disorder on measures reflecting psychopathological traits and 5HTTLPR (biallelic and triallelic) genotypes and alleles.

RESULTS

The highest-function, triallelic (L(A)/L(A)) genotype occurred significantly more frequently among eating-disordered individuals than among controls. However, a more fine-grained analysis suggested that this association was attributable to the fact that, among eating-disordered participants, those displaying an "Inhibited/Compulsive" profile (derived using latent class analysis) were more likely than those of a "Dissocial/Impulsive" or a "Low Psychopathology" group to carry the triallelic 5HTTLPR gain-of-function L(A) allele and to be L(A)/L(A) homozygotes.

DISCUSSION

This study's empirically derived classes coincide with interpretable differences on genetic indices-associating an "Inhibited/Compulsive" group with 5HTTLPR gain-of-function genotypes (and alleles) that have elsewhere been linked to trait compulsivity. The findings, furthermore, suggest that 5HTTLPR, by influencing personality-trait manifestations may, in turn, influence eating-disorder risk and symptom expression.

Development and persistence of posttraumatic stress disorder and the 5-HTTLPR polymorphism

Association between 5-HTTLPR polymorphism and development of acute and persistence of chronic posttraumatic stress disorder (PTSD) was prospectively investigated. DNA was extracted from 41 motor-vehicle accident victims evaluated for development and persistence of PTSD, 1 and 12 months posttrauma. At Time 1, a nonsignificant trend for higher acute PTSD rate in ll homozygotes (82%) was observed compared to those with ss and sl genotypes (50%). At Time 2, higher chronic PTSD rate was found in ll homozygotes (55%) compared to those with ss and sl genotypes (20%), with an odds ratio of 4.8 (95% CI = 1.09-21.22). Contrary to previous findings, these data are suggestive of a protective role for the s allele of 5-HTTLPR in chronic PTSD.

A serotonin transporter gene polymorphism (5-HTTLPR), drinking-to-cope motivation, and negative life events among college students

OBJECTIVE

This study was performed to examine whether a polymorphism (5-HTTLPR) in the serotonin transporter gene was related to college students' reports of relief drinking (drinking-to-cope motives) and whether it moderated the associations between negative life events and drinking to cope. We examined reward drinking (drinking-to-enhance motives) as a comparison and to see whether these effects varied across gender.

METHOD

Using an Internet-based survey, college students (N = 360; 192 women) self-reported on drinking motives and negative life events for up to 4 years. Study participants provided saliva for genotyping the triallelic (LA vs LG or S) variants of 5-HTTLPR.

RESULTS

Among men, individuals with two risk alleles (LG or S), compared with individuals with the LA/LA allele, displayed lower drinking-to-cope motives. Among women, individuals with one risk allele (either LG or S), compared with individuals with the LA/LA allele, displayed stronger drinking-to-enhance motives. The association between yearly changes in negative life events and drinking-to-cope motives varied across 5-HTTLPR genotype and gender and was strongest in the positive direction for women with the LA/LA variant.

CONCLUSIONS

Our findings are not consistent with prior speculation that stronger positive associations between life stress and alcohol use among individuals with the LG or S allele are the result of increased use of alcohol as a method for coping with stress. The importance of examining gender differences in the relations between 5-HTTLPR, substance use, and related constructs is also noted.

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.

Rapid switching of mood in families with familial bipolar disorder

OBJECTIVE

Rapid switching of moods in bipolar disorder has been associated with early age at onset, panic comorbidity, and suicidality. This study aims to confirm these associations and investigate other potential correlates of rapid switching of mood using families from a multisite bipolar linkage study.

METHODS

The subjects were comprised of 1,143 probands and relatives with diagnosis of bipolar disorder. All subjects were interviewed directly with a standard diagnostic instrument, and all subjects who met criteria for bipolar disorder were asked if their moods had ever switched rapidly.

RESULTS

Individuals with rapid mood switching had significantly earlier age at onset (18 versus 21 years, p < 0.00001), higher comorbid anxiety (47% versus 26%, p < 0.00001) and substance use disorders (52% versus 42%, p = 0.0006), higher rate of violent behavior (6% versus 3%, p < 0.004), suicidal behavior (46% versus 31%, p < 0.00001), and nonsuicidal self-harm (13% versus 6%, p < 0.0002). Multiple logistic regression analysis found significant net effects on rapid mood switching for early emergence of symptoms [odds ratio (OR) = 0.62; 95% confidence interval (CI): 0.45-0.85]; anxiety comorbidity (OR = 2.31; 95% CI: 1.34-3.98); and hypersensitivity to antidepressants (OR = 2.05; 95% CI: 1.49-2.83) as the strongest predictors.

CONCLUSIONS

This confirms earlier reports associating rapid switching with a more complex clinical course, in particular early emergence of bipolar symptomatology, antidepressant activation, and anxiety comorbidity. These results support a clinical differentiation of bipolar disorder into subtypes based on symptom stability.

Association of 5-HTT gene polymorphism, platelet MAO activity, and drive for thinness in a population-based sample of adolescent girls

OBJECTIVE

Several lines of evidence suggest that alterations in serotonergic activity contribute to the pathophysiology of abnormal eating behaviors. Since platelet monoamine oxidase (MAO) activity and the 5-HT transporter gene promoter polymorphism (5-HTTLPR) have been associated with eating disorders, the knowledge from a population-based sample may provide useful information which changes in 5-HT function observed in eating disorders represent trait vs. state effects.

METHOD

The sample was based on both cohorts of the Estonian Children Personality, Behavior and Health Study (ECPBHS). The current study was conducted during the second follow-up where altogether 82% from the original sample was recruited. EDI-2 subscales--Drive for Thinness and Bulimia--were used to determine eating attitudes and behaviors. Platelet MAO activity was measured and the participants were genotyped for the 5-HTTLPR.

RESULTS

Allelic variation of 5-HTTLPR or platelet MAO activity were not independently associated with drive for thinness or binge eating, but girls homozygous for the 5-HTTLPR long allele and with high platelet MAO activity, both considered indicators of a higher capacity 5-HT system, exhibited higher scores of drive for thinness.

CONCLUSION

The results suggest that drive for thinness is the highest in girls with the presence of two markers of higher serotonergic capacity.

[The neurobiology of impulse control disorders]

OBJECTIVE

To review the neurobiological substrates of impulse control disorders. Pathological gambling is a main focus of the review in that most biological studies of the formal impulse control disorders have examined this disorder.

METHOD

The medical database Medline from 1966 to present was searched to identify relevant articles that were subsequently reviewed to generate this manuscript.

RESULTS

Preclinical studies suggest that differential brain monoamine neuromodulation is associated with impulsive decision-making and risk-taking behaviors. Clinical studies implicate multiple neurotransmitter systems (serotonergic, dopaminergic, adrenergic, and opioidergic) in the pathophysiology of pathological gambling and other impulse control disorders. Initial neuroimaging studies have implicated the ventromedial prefrontal cortex and ventral striatum in the pathophysiology of pathological gambling and other impulse control disorders. Genetic contributions to pathological gambling seem substantial and initial studies have implicated specific allelic polymorphisms, although genome-wide analyses have yet to be published.

CONCLUSION

Although significant advances have been made in our understanding of the neurobiology of impulse control disorders, more research is needed to extend existing knowledge and translate these findings into clinical advances.

Neurobiology of anorexia and bulimia nervosa

Anorexia nervosa (AN) and bulimia nervosa (BN) are related disorders of unknown etiology that most commonly begin during adolescence in women. AN and BN have unique and puzzling symptoms, such as restricted eating or binge-purge behaviors, body image distortions, denial of emaciation, and resistance to treatment. These are often chronic and relapsing disorders, and AN has the highest death rate of any psychiatric disorder. The lack of understanding of the pathogenesis of this illness has hindered the development of effective interventions, particularly for AN. Individuals with AN and BN are consistently characterized by perfectionism, obsessive-compulsiveness, and dysphoric mood. Individuals with AN tend to have high constraint, constriction of affect and emotional expressiveness, ahendonia and asceticism, whereas individuals with BN tend to be more impulsive and sensation seeking. Such symptoms often begin in childhood, before the onset of an eating disorder, and persist after recovery, suggesting they are traits that create a vulnerability for developing an ED. There is growing acknowledgement that neurobiological vulnerabilities make a substantial contribution to the pathogenesis of AN and BN. Considerable evidence suggests that altered brain serotonin (5-HT) function contributes to dysregulation of appetite, mood, and impulse control in AN and BN. Brain imaging studies, using 5-HT specific ligands, show that disturbances of 5-HT function occur when people are ill, and persist after recovery from AN and BN. It is possible that a trait-related disturbance of 5-HT neuronal modulation predates the onset of AN and contributes to premorbid symptoms of anxiety, obsessionality, and inhibition. This dysphoric temperament may involve an inherent dysregulation of emotional and reward pathways which also mediate the hedonic aspects of feeding, thus making these individuals vulnerable to disturbed appetitive behaviors. Restricting food intake may become powerfully reinforcing because it provides a temporary respite from dysphoric mood. Several factors may act on these vulnerabilities to cause AN to start in adolescence. First, puberty-related female gonadal steroids or age-related changes may exacerbate 5-HT dysregulation. Second, stress and/or cultural and societal pressures may contribute by increasing anxious and obsessional temperament. Individuals with AN may discover that reduced dietary intake, by reducing plasma tryptophan availability, is a means by which they can modulate brain 5-HT functional activity and anxious mood. People with AN enter a vicious cycle which accounts for the chronicity of this disorder because caloric restriction results in a brief respite from dysphoric mood. However, malnutrition and weight loss, in turn, produce alterations in many neuropeptides and monoamine function, perhaps in the service of conserving energy, but which also exaggerates dysphoric mood. In summary, this article reviews findings in brain chemistry and neuroimaging that shed new light on understanding the psychopathology of these difficult and frustrating disorders.

Impulse control disorders in women with eating disorders

We compared symptom patterns, severity of illness, and comorbidity in individuals with eating disorders with and without impulse control disorders (ICD), and documented the temporal pattern of illness onset. Lifetime ICD were present in 16.6% of 709 women with a history of eating disorders. The most common syndromes were compulsive buying disorder and kleptomania. ICD occurred more in individuals with binge eating subtypes, and were associated with significantly greater use of laxatives, diuretics, appetite suppressants and fasting, and with greater body image disturbance, higher harm avoidance, neuroticism, cognitive impulsivity, and lower self-directedness. In addition, individuals with ICD were more likely to have obsessive-compulsive disorder, any anxiety disorder, specific phobia, depression, cluster B personality disorder, avoidant personality disorder, and to use psychoactive substances. Among those with ICD, 62% reported the ICD predated the eating disorder and 45% reported the onset of both disorders within the same 3-year window. The presence of a lifetime ICD appears to be limited to eating disorders marked by binge eating and to be associated with worse eating-related psychopathology, more pathological personality traits, and more frequent comorbid Axis I and II conditions. Untreated ICD may complicate recovery from eating disorders.

Dissocial behavior, the 5HTTLPR polymorphism, and maltreatment in women with bulimic syndromes

We recently reported that, among bulimic women, previously abused carriers of the 5HTTLPR S allele showed special propensities towards novelty seeking (implying recklessness or impulsivity) and interpersonal insecurity. We subsequently re-analyzed our data, to examine the bearing of the 5HTTLPR polymorphism and prior sexual or physical maltreatment upon validated, higher-order personality-traits. Ninety women with bulimic syndromes were genotyped for 5HTTLPR "short" (S) and "long" (L(G) and L(A)) alleles, and then assessed for eating symptoms, history of sexual or physical abuse, and the higher-order personality traits Emotional Dysregulation, Dissocial Behavior, Inhibition, and Compulsivity. With a classification based on a biallelic model of 5HTTLPR (i.e., presence or absence of at least one S-allele copy), multiple regression indicated a significant proportion of variance in Dissocial Behavior to be explained by an abuse x genotype interaction-greater psychopathology occurring in abused S-allele carriers. A parallel analysis applying a triallelic model of 5HTTLPR (i.e., presence or absence of at least one copy of presumably low-function S or L(G) alleles) produced a similar pattern, but no statistically significant effect. The finding that bulimic 5HTTLPR S-allele carriers who are previously abused display elevations on Dissocial Behavior corroborates previous observations concerning phenomenological correlates of traumatic stress in 5HTTLPR S allele carriers. (c) 2007 Wiley-Liss, Inc.

Contribution of the serotoninergic system to anxious and depressive traits that may be partially responsible for the phenotypical variability of bulimia nervosa

Eating disorders (ED), such as anorexia nervosa (AN) and bulimia nervosa (BN), are complex psychiatric phenotypes influenced by both genetic and environmental factors. We investigated the genetic contribution of four single nucleotide polymorphisms (SNPs) within the serotonin receptor 5HT2C and two sequence variants within the serotonin transporter SLC6A4 to different ED-related psychopathological symptoms in a total sample of 82 ED patients. All patients were diagnosed according to DSM-IV criteria and underwent diagnostic and psychopathological assessments by means of structured clinical interviews and rating scales. We detected significant evidence of association between the -995A/-759T/-697C/Cys23 haplotype of the 5HT2C gene and different anxious and depressive subscales of the SCL90-R instrument, that included Somatization (p = 0.029), Obsessive-Compulsiveness (p = 0.021), Depression (p = 0.032), Anxiety (p = 0.004), Hostility (p = 0.028), Phobic Anxiety (p = 0.029) and Paranoid Ideation (p = 0.008), in BN patients. We also observed a strong association between the 5HTTLPR polymorphism of the SLC6A4 gene and Anxiety in the same group of BN patients (p = 0.004). However, no epistatic effects between the 5HT2C and SLC6A4 genes on the different anxious and depressive subscales were observed. Our preliminary data suggest that the serotoninergic system contributes to the different psychopathological symptoms that may be partially responsible for the phenotypical variability within the bulimic phenotype.

A DRD4/BDNF gene-gene interaction associated with maximum BMI in women with bulimia nervosa

OBJECTIVE

The goals of the current study were threefold: 1) to examine whether the hypofunctional 7R allele of the DRD4 gene contributes to maximal lifetime body mass in women with BN; 2) to determine whether the BDNF gene contributes to maximal BMI on its own, and 3) to explore possible BDNF/DRD4 gene-gene interactions in mediating maximum lifetime BMIs in BN.

METHOD

We tested two General Linear Models predicting maximum lifetime BMI with the exon 3 VNTR polymorphism of the dopamine-4 receptor gene (DRD4) and either the Val66Met or the -270C/T polymorphism of BDNF respectively in 163 female probands with BN, purging subtype.

RESULTS

In these bulimic subjects, the hypofunctional 7R allele of DRD4 predicted maximal BMI (p < .01). There was also a significant interaction between the DRD4 gene and the BDNF gene in predicting maximal BMI. The Val66Met rather than the 270C/T polymorphism of BDNF interacting with DRD4 predicted maximum BMI in this BN sample (p < .01). Probands carrying both the hypofunctional 7R allele of DRD4 and the Met66 allele of BDNF had significantly higher maximal BMI than did probands in the other gene-gene interaction groups.

CONCLUSION

These results provide further evidence that the hypofunctional 7R allele of DRD4 contributes to weight gain in women with BN and that the BDNF gene interacts with DRD4 to influence weight regulation in these subjects.

Serotonin transporter binding after recovery from eating disorders

RATIONALE

Several lines of evidence suggest that altered serotonin (5-HT) function persists after recovery from anorexia nervosa (AN) and bulimia nervosa (BN).

OBJECTIVES

We compared 11 subjects who recovered (>1 year normal weight, regular menstrual cycles, no binging or purging) from restricting-type AN (REC RAN), 7 who recovered from bulimia-type AN (REC BAN), 9 who recovered from BN (REC BN), and 10 healthy control women (CW).

MATERIALS AND METHODS

Positron emission tomography (PET) imaging with [11C]McN5652 was used to assess the 5-HT transporter (5-HTT). For [11C]McN5652, distribution volume (DV) values were determined using a two-compartment, three-parameter tracer kinetic model, and specific binding was assessed using the binding potential (BP, BP=DVregion of interest/DVcerebellum-1).

RESULTS

After correction for multiple comparisons, the four groups showed significant (p<0.05) differences for [11C]McN5652 BP values for the dorsal raphe and antero-ventral striatum (AVS). Post-hoc analysis revealed that REC RAN had significantly increased [11C]McN5652 BP compared to REC BAN in these regions.

CONCLUSIONS

Divergent 5-HTT activity in subtypes of eating disorder subjects may provide important insights as to why these groups have differences in affective regulation and impulse control.

Interactive effects of sex and 5-HTTLPR on mood and impulsivity during tryptophan depletion in healthy people

BACKGROUND

Serotonin (5-HT) plays a central role in mood regulation and impulsivity. We studied whether healthy men and women react differently on mood and impulsivity measures during acute tryptophan depletion (ATD). We also studied the relative contribution of a functional length triallelic polymorphism in the promoter region of the serotonin transporter, designated 5-HTTLPR, to the behavioral responses to ATD.

METHODS

Thirty-nine men and 44 women participated in a randomized, double-blind, parallel group ATD study. Behavioral measures of impulsivity and mood were obtained.

RESULTS

During ATD, women reported mood reduction and showed a cautious response style, which is commonly associated with depression. Men showed an impulsive response style and did not report mood reduction. The 5-HTTLPR influenced the mood response to ATD in women.

CONCLUSIONS

Healthy men became more impulsive, whereas healthy women showed mood reduction in response to ATD. This suggests that 5-HT could be one mechanism contributing to the sex differences in the prevalence of mood and impulsivity disorders. The influence of 5-HTTLPR on mood responses in women further substantiates the relevance of this variant in the pathophysiology of at least a subgroup of patients with major depressive disorder.