Complex segregation analysis of obsessive-compulsive disorder in 141 families of eating disorder probands, with and without obsessive-compulsive disorder

Obsessive-compulsive symptoms in eating disorders: A network investigation

OBJECTIVE

Eating disorders (EDs) are complex, heterogeneous, and severe psychiatric syndromes. They are highly comorbid with obsessive-compulsive disorder (OCD) which exacerbates the course of illness and impedes treatment. However, the direct functional relations between EDs and OCD symptoms remain largely unexplored. Hence, using network analysis, we investigated the relationship between ED and OCD at the level of symptoms in a heterogeneous clinical sample.

METHOD

We used cross sectional data of 303 treatment-seeking patients with clinically relevant ED and OCD pathology. We constructed a regularized partial correlation network that featured both ED and OCD symptoms as nodes. To determine each symptom's influence, we calculated expected influence (EI) as an index of symptom centrality (i.e., "importance"). Bridge symptoms (i.e., symptoms from one syndromic cluster that have strong connections to symptoms of another syndromic cluster) were identified by computing bridge expected influence metrics.

RESULTS

Fear of weight gain and dietary restraint were especially important among the ED symptoms. Interference due to obsessions was the key feature of OCD. ED and OCD clustered distinctly with few potential bridges between clusters.

DISCUSSION

This study underscores the importance of cognitive symptoms for both ED and OCD although direct functional links between the two clusters are missing. Potentially, a network incorporating nodes capturing features of personality may account for diagnostic comorbidity better than specific symptoms of EDs or features of OCD do.

Cyfip1 Haploinsufficiency Increases Compulsive-Like Behavior and Modulates Palatable Food Intake in Mice: Dependence on Cyfip2 Genetic Background, Parent-of Origin, and Sex

Binge eating (BE) is a heritable trait associated with eating disorders and involves episodes of rapid, large amounts of food consumption. We previously identified cytoplasmic FMR1-interacting protein 2 (Cyfip2) as a genetic factor underlying compulsive-like BE in mice. CYFIP2 is a homolog of CYFIP1 which is one of four paternally-deleted genes in patients with Type I Prader-Willi Syndrome (PWS), a neurodevelopmental disorder whereby 70% of cases involve paternal 15q11-q13 deletion. PWS symptoms include hyperphagia, obesity (if untreated), cognitive deficits, and obsessive-compulsive behaviors. We tested whether Cyfip1 haploinsufficiency (+/−) would enhance compulsive-like behavior and palatable food (PF) intake in a parental origin- and sex-dependent manner on two Cyfip2 genetic backgrounds, including the BE-prone C57BL/6N (Cyfip2^N/N) background and the BE-resistant C57BL/6J (Cyfip2^J/J) background. Cyfip1^+/− mice showed increased compulsive-like behavior on both backgrounds and increased PF intake on the Cyfip2^N/N background. In contrast, maternal Cyfip1 haploinsufficiency on the BE-resistant Cyfip2^J/J background induced a robust escalation in PF intake in wild-type Cyfip1^J/J males while having no effect in Cyfip1^J/- males. Notably, induction of behavioral phenotypes in wild-type males following maternal Fmr1^+/− has previously been reported. In the hypothalamus, there was a paternally-enhanced reduction in CYFIP1 protein whereas in the nucleus accumbens, there was a maternally-enhanced reduction in CYFIP1 protein. Nochange in FMR1 protein (FMRP) was observed in Cyfip1^+/− mice, regardless of parental origin. To summarize, Cyfip1 haploinsufficiency increased compulsive-like behavior and induced genetic background-dependent, sex-dependent, and parent-of-origin-dependent effects on PF consumption and CYFIP1 expression that could have relevance for neurodevelopmental and neuropsychiatric disorders.

Genetic variability in the serotoninergic system and age of onset in anorexia nervosa and obsessive-compulsive disorder

The age of onset of some psychiatric disorders may have etiopathogenic and clinical effects and may influence outcome. Following on from previous work by our group where we showed that early onset anorexia nervosa (AN) and obsessive-compulsive disorder (OCD) shared a common genetic background, the aim of the present study is to assess genetic pleiotropy related to the serotonergic system (SLC6A4, 5HTR2A, 5HTR2C, TPH2, SLC18A1), in a common phenotype such as very-early age of onset. One hundred and sixteen adolescents diagnosed with AN and 74 adolescents diagnosed with OCD participated in the present study. We confirmed the existence of a genetic overlap between OCD and AN. Specifically, we described genetic pleiotropy for age at onset across these disorders, associating two SNPs (rs6311, rs4942587) of the HTR2A with the very-early onset phenotype.

[Genetics factors in pathogenesis and clinical genetics of binge eating disorder]

Genetic studies have shown that binge eating disorder (ВЕD) aggregates in families, heritability was estimated as about 60% and additive genetic influences on BED up to 50%. Using a genetic approach has proved useful for verifying the diagnostic categories of BED using DSM-IV criteria and supporting the validity of considering this pathology as a separate nosological category. The results confirmed the genetic and pathogenic originality of BED as a separate psychopathological phenomenon, but not a subtype of obesity. It seems fruitful to considerate BED as a disease with hereditary predisposition with significant genetic influence and a complex psychopathological syndrome, including not only eating disorders, but also depressive and addictive component. A possible mechanism of pathogenesis of BED may be the interaction of the neuroendocrine and neurotransmitters systems including the active involvement of the reward system in response to a variety of chronic stress influences with the important modulatory role of specific personality traits. The high level of genetic influence on the certain clinical manifestations of BED confirms the ability to identify the subphenotypes of BED on genetic basis involving clinical criteria. It can not only contribute to further genetic studies, taking into account more homogeneous samples, but also help in finding differentiated therapeutic approaches.

Genetic differences in the behavioral organization of binge eating, conditioned food reward, and compulsive-like eating in C57BL/6J and DBA/2J strains

Binge eating (BE) is a heritable symptom of eating disorders associated with anxiety, depression, malnutrition, and obesity. Genetic analysis of BE could facilitate therapeutic discovery. We used an intermittent, limited access BE paradigm involving sweetened palatable food (PF) to examine genetic differences in BE, conditioned food reward, and compulsive-like eating between C57BL/6J (B6J) and DBA/2J (D2J) inbred mouse strains. D2J mice showed a robust escalation in intake and conditioned place preference for the PF-paired side. D2J mice also showed a unique style of compulsive-like eating in the light/dark conflict test where they rapidly hoarded and consumed PF in the preferred unlit environment. BE and compulsive-like eating exhibited narrow-sense heritability estimates between 56 and 73%. To gain insight into the genetic basis, we phenotyped and genotyped a small cohort of 133 B6J × D2J-F₂ mice at the peak location of three quantitative trait loci (QTL) previously identified in F₂ mice for sweet taste (chromosome 4: 156 Mb), bitter taste (chromosome 6: 133 Mb) and behavioral sensitivity to drugs of abuse (chromosome 11: 50 Mb). The D2J allele on chromosome 6 was associated with greater PF intake on training days and greater compulsive-like PF intake, but only in males, suggesting that decreased bitter taste may increase BE in males. The D2J allele on chromosome 11 was associated with an increase in final PF intake and slope of escalation across days. Future studies employing larger crosses and genetic reference panels comprising B6J and D2J alleles will identify causal genes and neurobiological mechanisms.

Genetic susceptibility in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is present in 1.5-2.5% of the population and can result in substantial lifelong disability. It is characterized by intrusive thoughts, sensations, and urges and by repetitive behaviors that are difficult to control despite, in most cases, preserved insight as to their excessive or irrational nature. The causes and underlying pathophysiology of OCD are not well understood, which has limited the development of new treatments and interventions. Despite evidence for a substantial genetic contribution to disease risk, identification and replication of genetic variants associated with OCD have been challenging. Decades of candidate gene association studies have provided little insight. They are now being supplanted by modern genomewide approaches to discover both common and rare sequence and structural variants. Studies to date suggest potential novel therapeutic avenues such as modulators of glutamatergic and immune pathways; however, individual genetic findings are not yet statistically robust or replicated. Further efforts are clearly needed to identify specific risk variants and to confirm vulnerable pathways by studying much larger cohorts of patients with comprehensive variant discovery approaches. Mouse knockout models have already made notable inroads into our understanding of OCD pathology; their utility will only increase as specific risk alleles are identified.

Management of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common, often debilitating disorder characterized by the presence of obsessions and compulsions. Obsessions are repetitive thoughts or images which are experienced as intrusive and unwanted; they cause marked anxiety and distress. Compulsions (also known as rituals) are repetitive behaviors or mental acts that individuals with OCD perform in an attempt to decrease their anxiety. Patients tend to hide their symptoms due to shame; the amount of time between onset of symptoms and appropriate treatment is often many years. The disorder likely results from several etiological variables; functional imaging studies have consistently shown hyperactivity in the orbitofrontal cortex, anterior cingulate, thalamus, and striatum. The mainstays of treatment include cognitive-behavioral therapy in the form of exposure and response prevention (ERP) and serotonin reuptake inhibiting medications. Several pharmacological augmentation strategies exist for treatment-resistant OCD, with addition of antipsychotics being most commonly employed. Radio and neurosurgical procedures, including gamma knife radiation and deep brain stimulation, are reserved for severe, treatment-refractory disease that has not responded to multiple treatments, and some patients may benefit from transcranial magnetic stimulation.

Genetics of obsessive–compulsive disorder: a research update

The genetic study of obsessive-compulsive disorder (OCD) has made significant gains in the past decade. However, etiological gene findings are still elusive. Epidemiological studies, including family and twin studies, strongly support a genetic component for OCD. In addition, complex segregation analyses suggest the presence of at least one major gene. The neurobiology of OCD also lends support to the notion that programmed CNS-based biological processes underlie OCD symptom expression, with mapping of brain circuits to fronto-subcortical circuits in a consistent manner. Genetic linkage studies of OCD, using families with multiple affected relatives, have generated several suggestive linkage peaks, regions that may harbor a gene or genes for OCD. However, the presence of multiple linkage peaks has added to the complexity of OCD genetics, suggesting that the exploration of gene-gene interactions and gene-environment interactions, in addition to the exploration of alternate phenotypes based on symptom expression, age at onset or comorbid conditions, may be key in locating etiologic genes. Finally, candidate gene studies, while promising, are not yet associated with linkage regions, except in the case of the glutamate transporter gene SLC1A1 in 9p24. While OCD appears to have a genetic component, additional innovative research is needed to unravel the genetic influences in the disorder.

Common genetic background in anorexia nervosa and obsessive compulsive disorder: preliminary results from an association study

Several lines of evidence, including psychopathological, neurobiological, pharmacological and epidemiological data, supported the association between Anorexia Nervosa (AN) and Obsessive-Compulsive Disorder (OCD). The aim of the present study is to test the hypothesis of partial common genetic background of both disease, AN and OCD. A total of 116 patients with AN, 74 patients with OCD and 91 controls participated in this study. 213 single-nucleotide polymorphisms (SNPs) in 28 candidate genes were analyzed. Five SNPs achieved 0.004 (the nominal p-value expected by chance), 3 with empirical significant p-values (rs10070190 (CDH9) p = 1 × 10(-3), rs4825476 (GRIA3) p = 4 × 10(-4), and rs1074815 (TPH2) p = 8 × 10(-4)) and 2 additional polymorphisms showing nominal significance (rs2834070 (OLIG2) p = 2 × 10(-3) and rs11783752 (SCL18A1) p = 3 × 10(-3)), were found to be related to both AN and OCD. In addition, rs3825885 (NTRK3, p = 9 × 10(-4)) was identified as an AN risk variant, and rs11179027 (TPH2, p = 2 × 10(-3)) as an OCD marker. The ROC analysis confirmed these results and showed interaction among the significant SNPs. The preliminary results we report here reveal a partial common genetic background in AN and OCD, in agreement with previous clinical findings of common symptomathology between these two diseases and open the field of possible treatments for AN. The interaction observed between the associated polymorphisms, could indicate that there is a biological interaction between the serotonin (TPH2 and SLC18A1) and glutamate (GRIA3) pathways and the factors related to neurogenesis (CDH9, OLIG2 and NTRK3) for the explanation of etiopathophysiology in both diseases. However, the results must be replicated in studies with larger cohorts in order to confirm these associations.

Genome-wide linkage analysis of obsessive-compulsive disorder implicates chromosome 1p36

BACKGROUND

Obsessive-compulsive disorder (OCD) has a complex etiology involving both genetic and environmental factors. However, the genetic causes of OCD are largely unknown, despite the identification of several promising candidate genes and linkage regions.

METHODS

Our objective was to conduct genetic linkage studies of the type of OCD thought to have the strongest genetic etiology (i.e., childhood-onset OCD), in 33 Caucasian families with ≥2 childhood-onset OCD-affected individuals from the United States (n = 245 individuals with genotype data). Parametric and nonparametric genome-wide linkage analyses were conducted with Morgan and Merlin in these families using a selected panel of single nucleotide repeat polymorphisms from the Illumina 610-Quad Bead Chip. The initial analyses were followed by fine-mapping analyses in genomic regions with initial heterogeneity logarithm of odds (HLOD) scores of ≥2.0.

RESULTS

We identified five areas of interest (HLOD score ≥2) on chromosomes 1p36, 2p14, 5q13, 6p25, and 10p13. The strongest result was on chromosome 1p36.33-p36.32 (HLOD = 3.77, suggestive evidence for linkage after fine mapping). At this location, several of the families showed haplotypes co-segregating with OCD.

CONCLUSIONS

The results of this study represent the strongest linkage finding for OCD in a primary analysis to date and suggest that chromosome 1p36, and possibly several other genomic regions, may harbor susceptibility loci for OCD. Multiple brain-expressed genes lie under the primary linkage peak (approximately 4 megabases in size). Follow-up studies, including replication in additional samples and targeted sequencing of the areas of interest, are needed to confirm these findings and to identify specific OCD risk variants.

Genetics of pediatric anxiety disorders

This article reviews the familiality, linkage, candidate gene, and genomewide association studies of obsessive-compulsive disorder, panic disorder, posttraumatic stress disorder, and other anxiety disorders (ie, generalized anxiety disorder, separation anxiety disorder, social phobia, and specific phobia). Studies involving children and adolescents are highlighted. Clinical and research implications are discussed.

The genetics of obsessive-compulsive disorder: a review

Obsessive-compulsive disorder (OCD) is a serious psychiatric disorder that affects approximately 2% of the populations of children and adults. Family aggregation studies have demonstrated that OCD is familial, and results from twin studies demonstrate that the familiality is due in part to genetic factors. Only three genome-wide linkage studies have been completed to date, with suggestive but not definitive results. In addition, over 80 candidate gene studies have been published. Most of these studies have focused on genes in the serotonergic and dopaminergic pathways. Unfortunately, none have achieved genome-wide significance, and, with the exception of the glutamate transporter gene, none have been replicated. Future research will require the collaboration of multidisciplinary teams of investigators to (i) achieve sufficiently large samples of individuals with OCD; (ii) apply the state-of-the-art laboratory techniques; and (iii) perform the bioinformatic analyses essential to the identification of risk loci.

Overview of genetics and obsessive-compulsive disorder

This paper reviews the current state of research into the genetics of obsessive-compulsive disorder (OCD). Heredity has a major role in OCD etiology. This evidence comes from several methodological approaches such as family, twin, and segregation analysis studies. A major single gene effect as well as a polygenic hypothesis has been suggested based on segregation studies. In addition, candidate gene association and linkage analyses have shown not only one gene, but a few interesting genes and areas of the genome that may be relevant in OCD. In this search for genes, new definitions of the OCD phenotype have emerged, and some of them may be considered intermediate phenotypes between the gene effect and OCD-DSM-IV diagnosis. The phenotypic and genetic heterogeneity of OCD magnifies the challenge of locating susceptibility genes; at the same time, the identification of vulnerability genes will elucidate the identification of subtypes or dimensions of the disorder. Therefore research strategies that take advantage of clinical subtyping and that redefine the OCD phenotype in the context of genetic studies may potentially contribute to the nosology of OCD and ultimately pathophysiology. There is a lack of understanding about how genes and environment interact in OCD. However, there are some reports that will be discussed, which have attempted to evaluate how the environment contributes to OCD.

The genetics of obsessive compulsive disorder: a review of the evidence

Obsessive compulsive disorder (OCD) is a common psychiatric disorder that can have disabling effects on both adults and children. Twin, family, segregation, and linkage studies have demonstrated that OCD is familial, that the familiality is due in part to genetic factors and there are regions of the genome which very likely harbor susceptibility loci for OCD. Over 60 candidate gene studies have been conducted. Most studies have focused on genes in the serotonergic and dopaminergic pathways. Unfortunately, none have achieved genome-wide significance and with the exception of the glutamate transporter gene, none have been reliably replicated. Future research will requite much larger samples and the collaboration of researchers to be able to identify susceptibility loci for OCD.

Genetic and environmental influences on obsessive-compulsive disorder

It is important to understand how genetic and environmental factors interact in the development of obsessive-compulsive disorder (OCD) in order to provide a cohesive model of the underlying pathogenic mechanisms. In this article, we provide an overview of the current knowledge of possible genetic and environmental contributions to the development of OCD. We consider the significant challenges for identifying risk factors for OCD as well as promising avenues for overcoming these obstacles in future research. In particular, we discuss the value of focusing on certain phenotypes, applying a dimensional approach, and investigating possible endophenotypes. We also describe innovative study designs that may be used in future research to explore the interaction between genetic vulnerability and environmental risk factors for OCD.

Obsessive-compulsive and eating disorders: comparison of clinical and personality features

The aim of the present study was to determine whether anorexia nervosa (AN), bulimia nervosa (BN) and obsessive-compulsive disorder (OCD) share clinical and psychopathological traits. The sample consisted of 90 female patients (30 OCD; 30 AN; 30 BN), who had been consecutively referred to the Department of Psychiatry, University Hospital of Bellvitge, Barcelona. All subjects met DSM-IV criteria for those pathologies. The assessment consisted of the Maudsley Obsessive-Compulsive Inventory (MOCI), Questionnaire of obsessive traits and personality by Vallejo, Eating Attitudes Test-40 (EAT-40), Eating Disorder Inventory (EDI), and Beck Depression Inventory (BDI). ANCOVA tests (adjusted for age and body mass index) and multiple linear regression models based on obsessive-compulsiveness, obsessive personality traits and perfectionism, as independent variables, were applied to determine the best predictors of eating disorder severity. On ancova several significant differences were found between obsessive-compulsive and eating-disordered patients (MOCI, P < 0.001; EAT, P < 0.001; EDI, P < 0.001), whereas some obsessive personality traits were not eating disorder specific. A total of 16.7% OCD patients presented a comorbid eating disorder, whereas 3.3% eating disorders patients had an OCD diagnosis. In the eating disorder group, the presence of OC symptomatology was positively associated (r = 0.57, P < 0.001) with the severity of the eating disorder. The results were maintained after adjusting for comorbidity. Although some obsessive-compulsive and eating disorder patients share common traits (e.g. some personality traits especially between OCD and AN), both disorders seem to be clinically and psychopathologically different.

Heritability and clinical features of multigenerational families with obsessive-compulsive disorder and hoarding

To date, only one complete genome screen for obsessive-compulsive disorder (OCD) has been published. That study identified a region of suggestive linkage (maximum lod score of 2.25) with a relatively small sample size (N = 56; 27 with OCD). Additional complete genome screens are needed to confirm this finding and identify other regions of linkage. We present the clinical characteristics and power to detect linkage of 11 multigenerational families with OCD and hoarding (N = 92; 44 with OCD), as well as heritability estimates for several quantitative traits. Families with at least two individuals with OCD were identified through probands with childhood-onset OCD. Expected lod scores were calculated for simulated genetic marker data under an additive and two dominant models assuming a dense SNP marker map. All affected individuals had an early age of onset (18 or younger). Hoarding was present in 46% of subjects. Obsessive-compulsive symptoms and hoarding were highly heritable. The maximum mean expected lod score was 3.31 for OCD and 1.39 for hoarding. We found reasonable power to detect regions of interest (lod = 2) for OCD in these families, but will need to expand our family collection to have adequate power to detect regions of interest for hoarding.

Estado atual da clínica psiquiátrica do transtorno obsessivo-compulsivo

Este artigo revisa a literatura sobre o transtorno obsessivocompulsivo com o objetivo de informar o estado atual da pesquisa científica nesse tema. Os autores citam a literatura internacional buscando enfatizar a pesquisa nacional, principalmente a pesquisa do seu grupo, o Projeto Transtornos do espectro Obsessivo-compulsivo.

Decision-making functioning as a predictor of treatment outcome in anorexia nervosa

The pathological eating behaviour of patients with anorexia nervosa reflects a deficit in planning real-life strategies that can be observed in an experimental setting through the Gambling Task, a tool designed to detect and measure decision-making abilities. We examined the role of Gambling Task performance as a predictor of treatment outcome in anorectic patients, and we evaluated changes in decision-making after clinical improvement. Performance on the Gambling Task was evaluated, and a clinical-nutritional assessment of 38 anorectic patients was carried out before and after a cognitive-behavioural and drug treatment program. Task performance of anorectic patients was compared with that of 30 healthy control participants. Patients who had a better decision-making profile at baseline showed significantly greater improvement in nutritional status. The decision-making deficiency of some anorectic patients is probably linked to those individual features that contribute to the phenomenological expression of the disorder and to its different treatment outcomes.

The genetic studies of obsessive-compulsive disorder and its future directions

Obsessive-compulsive disorder (OCD) is characterized by recurrent and persistent thoughts (obsessions), and repetitive behaviors or mental acts (compulsions). In Korea, an epidemiological study reported that the lifetime prevalence of OCD in the population was greater than two percent. The exact cause of OCD is still unknown. Evidence from familial, twin and segregation studies supports the role of a genetic component in the etiology of OCD. In addition, there is growing evidence that OCD has a specific neurochemical and neuroanatomical basis. According to this evidence, researchers have selected various candidate genes which have been implicated in the neurophysiology of OCD, and differences of allelic variants in OCD patients and controls have been analyzed. In this review we will introduce the results of previous genetic studies of OCD which have been performed in other populations, including twin studies, family studies, segregation analyses, linkage analyses, and association studies. In addition to these studies, we will present the results of our genetic studies of OCD performed in Korea.

Genomewide linkage scan for obsessive-compulsive disorder: evidence for susceptibility loci on chromosomes 3q, 7p, 1q, 15q, and 6q

Obsessive-compulsive disorder (OCD) is the tenth most disabling medical condition worldwide. Twin and family studies implicate a genetic etiology for this disorder, although specific genes have yet to be identified. Here, we present the first large-scale model-free linkage analysis of both extended and nuclear families using both 'broad' (definite and probable diagnoses) and 'narrow' (definite only) definitions of OCD. We conducted a genome-scan analysis of 219 families collected as part of the OCD Collaborative Genetics Study. Suggestive linkage signals were revealed by multipoint analysis on chromosomes 3q27-28 (P=0.0003), 6q (P=0.003), 7p (P=0.001), 1q (P=0.003), and 15q (P=0.006). Using the 'broad' OCD definition, we observed the strongest evidence for linkage on chromosome 3q27-28. The maximum overall Kong and Cox LODall score (2.67) occurred at D3S1262 and D3S2398, and simulation based P-values for these two signals were 0.0003 and 0.0004, respectively, although for both signals, the simulation-based genome-wide significance levels were 0.055. Covariate-linkage analyses implicated a possible role of gene(s) on chromosome 1 in increasing the risk for an earlier onset form of OCD. We are currently pursuing fine mapping in the five regions giving suggestive signals, with a particular focus on 3q27-28. Given probable etiologic heterogeneity in OCD, mapping gene(s) involved in the disorder may be enhanced by replication studies, large-scale family-based linkage studies, and the application of novel statistical methods.

The serotonin-1Dbeta receptor gene and severity of obsessive-compulsive disorder in women with bulimia nervosa

BACKGROUND

There is significant evidence that eating disorders have an important biological overlap with obsessive-compulsive disorder (OCD), though the specific mediators of this relationship remain unclear. Recent evidence suggests that the G861C polymorphism of the 5HT-1Dbeta receptor gene and the G allele in particular may play a role in OCD. We thus hypothesized that, among a heterogenous group of probands with bulimia nervosa (BN), this same G allele might predict the presence and/or severity of OCD pathology.

METHODS

165 consecutive female probands with BN were genotyped for the G861C polymorphism of the 5HT-1Dbeta receptor gene. Rates of full syndrome OCD, partial syndrome OCD and no OCD were compared across the three genotypic groups defined by this polymorphism.

RESULTS

45 out of 165 BN probands (27.3%) had either full or partial syndrome OCD. In the full sample, there was a significant difference in the distribution of the three diagnostic groups by genotype (chi2=10.07, df=4, p=.039). The G861C polymorphism did not strongly predict which probands had any vs. no OCD pathology. However, among the 45 probands with OCD symptoms, the G861C polymorphism did strongly differentiate full syndrome vs. partial syndrome OCD (chi2=9.26, df=2, p=.01; odds ratio for full syndrome OCD with GG genotype=7.69, 95% CI=1.45-40.9).

DISCUSSION

In women with BN, the G861C polymorphism of the 5HT-1Dbeta gene does not appear to be associated with the generation of OCD symptoms; however, it might directly or indirectly be associated with a modulatory effect on syndrome severity in probands otherwise predisposed to OCD. While preliminary and in need of replication in other samples, this is the first association study to suggest how a particular gene might influence OCD pathology in an eating disorder population.

Early-onset obsessive-compulsive disorder: a subgroup with a specific clinical and familial pattern?

BACKGROUND

The familial nature of obsessive-compulsive disorder (OCD) has been previously demonstrated. The identification of candidate symptoms such as age at onset may help to disentangle the clinical and genetic heterogeneity of the disorder. In this study, the specificity of early-onset OCD was investigated, focusing on the effect of gender, comorbid conditions and familial risk of tics and OCD by studying a population consisting exclusively of patients with early-onset OCD.

METHODS

One hundred and forty-four patients having OCD were recruited in the study (108 early-onset probands and 36 late-onset probands). The early-onset probands and 199 of their first-degree relatives were investigated using structured interviews and questionnaires. This sample of early onset was mainly composed of children and adolescents (74 children and adolescents and 34 adults).

RESULTS

The average age of onset of OCD is 9.98+/-3.2 years. Forty-four per cent of the probands have a comorbid tic disorder. The age-corrected morbid risk among the first-degree relatives is 17% for OCD and 12% for tics. Morbid risk for OCD and tics was independent of the presence of tics in probands. Only 32.6% of the probands have a positive family history of OCD.

CONCLUSIONS

These findings are consistent with other reports in the literature that the morbid risk of OCD is elevated in relatives of probands with early-onset OCD. However, the majority of cases do not have a positive family history of OCD. This result suggests that early onset is not the only specific clinical marker for familial risk in OCD. Thus more work is needed to clearly elucidate other factors related to increased genetic vulnerability for OCD.

Complex segregation analysis of obsessive-compulsive disorder in families with pediatric probands

OBJECTIVE

The purpose of this study was to assess the mode of inheritance for obsessive-compulsive disorder (OCD) in families ascertained through pediatric probands.

METHODS

We ascertained 52 families (35 case and 17 control families) through probands between the ages of 10 and 17 years. Direct interviews were completed with 215 individuals. Family informant data were collected on another 450 individuals without direct interviews, forming two data sets with one contained within the other. Complex segregation analyses were performed using regressive models as programmed in REGTL in the S.A.G.E. package. All models used in the analyses included sex-specific age and type parameters.

RESULTS

All models that excluded a residual effect of an affected parent were rejected. With that parameter included, the environmental and sporadic models were rejected in comparisons with the most general model in both data sets (all p < 0.005). With the direct interview data, the general codominant Mendelian model was not rejected when compared with the most general model (p = 0.140). We could not distinguish between any of the simple Mendelian models using either data set. However, the dominant Mendelian model provided a somewhat better fit than the other Mendelian models to the direct interview data.

CONCLUSIONS

The results provide evidence for a major susceptibility locus in families with OCD when age at onset is incorporated into the model. Mendelian factors at most partially explained the familial aggregation of the phenotype, and residual familial effects were necessary to fit the data adequately. The results support the importance of linkage efforts by suggesting that a major locus is segregating within a proportion of families with OCD ascertained through pediatric probands.

Neuropsychological investigation of decision-making in anorexia nervosa

Anorexia nervosa (AN) could be considered a form of obsessive-compulsive disorder in which an impairment of the cognitive domain related to decision-making was found. We explored this function in AN patients, as well as possible differences between restricting type and binge/purge type, with the aim of examining the hypothesis that AN is part of the obsessive-compulsive spectrum. Decision-making was assessed in 59 inpatients with AN and 82 control subjects using the Gambling task, which simulates real-life decision-making by assessing the ability to balance immediate rewards against long-term negative consequences. We confirmed the supposed deficit of decision-making in AN. However, restricting and binge eating/purge subtypes showed different patterns of decision-making impairment. Poor performance on the Gambling task is not a mere consequence of starvation and does not appear to be related to illness severity. The decision-making deficiency that some AN patients show is linked to those individual features that contribute to the phenomenological expression of the disorder.

Association of the 5-HT2c gene with susceptibility and minimum body mass index in anorexia nervosa

The association between a non-conservative Cys23Ser in the 5-HT2c gene and anorexia nervosa in females was examined. We used case-controls and family based association analysis in a sample of 118 patients with DSMIV anorexia nervosa, 244 controls and 47 family trios. There was a significant increase in the frequency of the Ser23 allele in the patients by allele (18.8% vs 12.8%; p = 0.026; OR 1.58, 95% CI 1.0-2.4) and genotype (32.2% vs 19.9%; genotype-wise p = 0.027). There was significant correlation between genotype and minimum BMI (r2 = 0.056; p = 0.01), indicating that the Ser23 allele has an effect on severity of illness. We performed TDT analysis using a sub-sample of the cases (58) for whom both parents were available and we found an excess transmission of the Ser23 allele (p = 0.05). Our findings are consistent a role for the Ser23 allele of 5-HT2c in mediating susceptibility to and increasing severity of anorexia nervosa.

Transtornos alimentares e os espectros do humor e obsessivo-compulsivo

Revisamos os estudos clínicos e biológicos que sugerem que os transtornos alimentares (TA) são expressões fenotípicas de outros transtornos psiquiátricos e parte de espectros de psicopatologia, em especial dos espectros dos transtornos do humor e do transtorno obsessivo-compulsivo. A investigação da relação entre os TA e outros transtornos psiquiátricos através dos modelos espectrais pode proporcionar um melhor entendimento da fisiopatologia destas síndromes e a elaboração de tratamentos mais eficazes. Entretanto, o reconhecimento de que os TA possuem características peculiares e a adoção de uma postura crítica em relação a modelos que eliminam limites diagnósticos são também fundamentais para a evolução do conhecimento no campo.

Bulimia nervosa: an update and treatment recommendations

Bulimia nervosa is a common eating disorder in adolescent women. Biological, psychological, and social factors are implicated in onset and important in treatment. Diagnosis of the syndrome, but not its subtypes, can be made well using the DSM-IV system. Screening tools, laboratory findings, and physical findings can be helpful in making the diagnosis. Comorbid disorders include affective disorders, addictive disorders, anxiety disorders, personality disorders, and anorexia nervosa. The etiology of bulimia nervosa is complex, with biologic, psychological, social, and family factors, which likely differ somewhat from patient to patient. Treatment, accordingly, should be comprehensive, individualized, and multifaceted. Many patients respond well to the use of an antidepressant, and cognitive-behavioral therapy is a useful approach for many patients. Combining these two treatments seems to be a good strategy. Environmental and family issues also need to be addressed. Many patients are treated insufficiently. More research on bulimia nervosa specific to adolescence is needed.

Neurobiology and clinical pharmacology of obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a brain disorder with recognizable periods of onset, course, familial occurrence, epidemiology, phenomenology, and treatment response. Several manifestations of pathophysiology are beginning to be defined, although they may represent intermediate pathophysiology rather than primary etiology. Positron emission tomography studies have consistently identified hypermetabolism in the orbitofrontal cortex, caudate nucleus, and, sometimes, anterior cingulate cortex. Neuropsychologic testing frequently identifies abnormalities in visuospatial function. Abnormal levels of cerebrospinal fluid neurotransmitters and neuromodulators are identifiable in untreated patients with OCD and return toward normal levels after effective treatment. The most consistent pathophysiologic finding in OCD points toward an abnormality in serotonin neurotransmission. Therapeutic response to selective serotonin reuptake inhibitors and the absence of improvement with norepinephrine reuptake inhibitors and dopamine antagonists argue strongly for a role of serotonin in the pathophysiology and treatment of OCD. Despite this clear indication from treatment trials, probes and manipulations of the serotonin system and its specific receptors have not provided a useful understanding of specific abnormalities. Clomipramine or potent selective serotonin reuptake inhibitors are the pharmacotherapy of choice for OCD, with a more limited role reserved for monoamine oxidase inhibitors. If one selective serotonin reuptake inhibitor is ineffective, others may be beneficial, in addition to the different proserotonergic and nonserotonergic augmentation strategies that could be useful in treatment of resistant OCD patients. Nondrug therapies are also important in OCD: behavioral therapy is frequently helpful and neurosurgery is sometimes helpful when other treatments fail.

Complex segregation analysis provides compelling evidence for a major gene underlying obsessive-compulsive disorder and for heterogeneity by sex

Evidence from twin and family studies supports a genetic etiology for obsessive-compulsive disorder (OCD). The purpose of this study was to test whether a major gene is implicated in a proportion of families with OCD. Complex segregation analyses of 153 families (80 case and 73 control), ascertained in the Johns Hopkins OCD Family Study, provided strong evidence for a major gene. A Mendelian-dominant model, with significant sex effects and with residual familial effects, best explained the observed data. Stratification of the sample by the sex of probands provided further evidence of heterogeneity with respect to familial aggregation. Segregation analyses of 86 families with a female proband and of the 67 families with a male proband suggested that a Mendelian-dominant model with familial residual effects was the most parsimonious model explaining the inheritance of OCD in both subgroups.