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

Non-suicidal self-injury among individuals with an eating disorder: A systematic review and prevalence meta-analysis

OBJECTIVE

This study aimed to quantify the prevalence of non-suicidal self-injury across eating disorders (EDs) and within diagnostic categories through systematic review and proportional, or so-called prevalence, meta-analysis.

METHOD

Included studies had to contain individuals with a verified diagnosis of an ED. The last literature search was conducted on September 11, 2023, for studies published on or before September 2023 without a restriction on earliest publication year. Results were synthesized and analyzed using the "metaprop" package in R and presented using forest plots. Bias was assessed by a Peters' regression test and funnel plot.

RESULTS

79 studies published between 1985 and 2023 were included encompassing 32,334 individuals with an ED. Importantly, 42 studies were not included in any other meta-analyses on self-injury in EDs to date. Overall prevalence of non-suicidal self-injury was 34.59% (95%CI = 30.49-38.81). Prevalence in anorexia nervosa restrictive type, binge/purge type, bulimia nervosa, binge eating disorder and other specified feeding/eating disorder were 23.19% (95%CI = 16.96-30.03%), 41.98% (95%CI = 32.35-51.91%), 36.97% (95%CI = 30.69-43.46%), 21.21% (95%CI = 14.93-28.12%) and 37.65% (95%CI = 28.59-47.09%), respectively. Prevalence estimations could not be estimated for other ED categories due to lack of a sufficient number of studies.

DISCUSSION

Non-suicidal self-injury is prevalent across both binge/purge and restrictive EDs. Considering the transdiagnostic nature of self-injurious behaviors in ED, the results highlight the importance of assessment and monitoring of self-injury in people with ED, irrespective of specific diagnoses. The method of determining self-injury varied across studies and may limit this study.

PUBLIC SIGNIFICANCE

This study highlights the prevalence of self-injury across eating disorders irrespective of diagnosis and within specific EDs. While diagnoses known to exhibit self-injurious behaviors (e.g., bulimia nervosa, anorexia nervosa binge/purge subtype) demonstrated the highest prevalence of self-injury, all diagnoses were found to have a prevalence greater than 20%. These findings suggest the importance of assessing and monitoring all individuals with an eating disorder for the presence of self-injury.

Advancing a temporal framework for understanding the biology of nonsuicidal self- injury: An expert review

Nonsuicidal self-injury (NSSI) is a serious clinical problem, particularly for adolescents and young adults. NSSI is a complex behavior that emerges through the intersecting effects of social, psychological, and biological mechanisms. Although the social and psychological contributions to risk for developing NSSI are relatively well understood and have guided the development of effective psychosocial treatments for self-injury, the biological mechanisms underlying NSSI have just begun to come to light. To evaluate and categorize the biological research conducted on the topic of NSSI, we propose a model that distinguishes between trait and state markers. According to this model, risk factors and mechanisms involved in NSSI can be distinguished into both trait and state factors. We review the existing evidence on distal biological traits (predictors) of NSSI, proximal biological traits (correlates) of NSSI, and biological states directly preceding or following NSSI. We conclude by providing recommendations for future research on the neurobiology of NSSI.

Eating Disorders and Epigenetics

Eating disorders (EDs) are characterized by intense preoccupation with shape and weight and maladaptive eating practices. The complex of symptoms that characterize EDs often arise through the activation of latent genetic potentials by environmental exposures, and epigenetic mechanisms are believed to link environmental exposures to gene expression. This chapter provides an overview of genetic factors acting in the etiology of EDs. It then provides a background to the hypothesis that epigenetic mechanisms link stresses such as obstetric complications and childhood abuse as well as effects of malnutrition to eating disorders (EDs). The chapter then summarizes the emerging body of literature on epigenetics and EDs-mainly studies on DNA methylation in samples of anorexia and bulimia. The available evidence base suggests that an epigenetically informed perspective contributes in valuable ways to the understanding of why people develop EDs.

Serotonin transporter gene polymorphism in eating disorders: Data from a new biobank and META-analysis of previous studies

Objectives Growing interest focuses on the association between 5-HTTLPR polymorphism and eating disorders (ED), but published findings have been conflicting. Methods The Italian BIO.VE.D.A. biobank provided 976 samples (735 ED patients and 241 controls) for genotyping. We conducted a literature search of studies published up to 1 April 2015, including studies reporting on 5HTTLPR genotype and allele frequencies in obesity and/or ED. We ran a meta-analysis, including data from BIO.VE.D.A. - comparing low and high-functioning genotype and allele frequencies in ED vs.

CONTROLS

Results Data from 21 studies, plus BIO.VE.D.A., were extracted providing information from 3,736 patients and 2,707 controls. Neither low- nor high-functioning genotype frequencies in ED patients, with both bi- and tri-allelic models, differed from controls. Furthermore, neither low- nor high-functioning allele frequencies in ED or in BN, in both bi- and triallelic models, differed from control groups. After sensitivity analysis, results were the same in AN vs.

CONTROLS

Results remained unaltered when investigating recessive and dominant models. Conclusions 5HTTLPR does not seem to be associated with ED in general, or with AN or BN in particular. Future studies in ED should explore the role of ethnicity and psychiatric comorbidity as a possible source of bias.

Does shared genetic risk contribute to the co-occurrence of eating disorders and suicidality?

OBJECTIVE

There is a high level of co-occurrence of suicidality with eating disorders (EDs) but the reason for this is unknown. To test the hypothesis that suicidality and EDs share genetic risk contributing to the expression of both phenotypes.

METHOD

Female twins (N = 1,002) from the Australian Twin Registry, aged 28-40 years, were interviewed with diagnostic interviews. Lifetime diagnostic information relating to eating disorders [anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder, and purging disorder (PD)], suicidality (ranging transitory thoughts to suicide attempts), and major depression.

RESULTS

Any suicidal thoughts were reported by 24% of the sample, but prevalence of lifetime suicidality among female twins with EDs was much higher (43%), presence of an ED diagnosis more than doubling likelihood of suicidality (OR = 2.32, 95% CI: 1.63-3.31). AN and BN conveyed greatest risk of suicidality (OR = 2.03, 95% CI: 1.06-3.87; OR = 3.97, 95% CI: 2.01-7.85, respectively). Twin phenotype correlations showed monozygotic twins had uniformly higher estimates than dizygotic counterparts. A trivariate Cholesky model indicated a common genetic influence on suicidality and ED phenotypes (but not depression), and no nonshared environmental source.

DISCUSSION

Both cross twin phenotypic correlations and genetic modeling infer a common genetic pathway for suicidality and EDs, but further investigation is needed to elucidate whether this may constitute emotional dysregulation or other temperament-linked factors. Study findings also indicate that ED clients must be routinely assessed for presence of suicidality, independent of depression status.

Genetics and Epigenetics of Eating Disorders

Eating disorders (EDs) are serious psychiatric conditions influenced by biological, psychological, and sociocultural factors. A better understanding of the genetics of these complex traits and the development of more sophisticated molecular biology tools have advanced our understanding of the etiology of EDs. The aim of this review is to critically evaluate the literature on the genetic research conducted on three major EDs: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). We will first review the diagnostic criteria, clinical features, prevalence, and prognosis of AN, BN, and BED, followed by a review of family, twin, and adoption studies. We then review the history of genetic studies of EDs covering linkage analysis, candidate gene association studies, genome-wide association studies, and the study of rare variants in EDs. Our review also incorporates a translational perspective by covering animal models of ED-related phenotypes. Finally, we review the nascent field of epigenetics of EDs and a look forward to future directions for ED genetic research.

Temperamental and genetic predictors of suicide attempt and self-mutilation

BACKGROUND AND AIMS

Literature findings mainly support the notion that suicide attempts (SA) and self-mutilating behavior (SMB) are distinct behaviors, although they may share common psychopathological features. In the present paper we aimed to identify behavioral phenotypes in patients with SA, SMB, or both (SAM) and to analyze the association with candidate genes.

METHODS

One hundred forty-two inpatients with a history of SA (n = 86), SMB (n = 22), and SAM (n = 39) were included in this study. Subjects were evaluated using the Tridimensional Personality Questionnaire (TPQ) and the Buss-Durkee Hostility Inventory (BDHI). Polymorphisms within serotonin transporter (SLC6A4, HTTLPR), catechol-O-methyl transferase (COMT, Val158Met), and tryptophan hydroxylase (TPH, 218C>A) were also analyzed.

RESULTS

Principal component factor analysis including the BDHI and TPQ produced 3 factors that could classify the 3 groups of patients with good sensitivity. However, only the 'pure suicidal' factor had a sufficient positive predictive value. This factor was characterized by high levels of persistence (PS) and, to a lower extent, reward dependence. The distribution of genotypes was not different across patient groups for all polymorphisms, but the SS genotype of HTTLPR was significantly associated with the 'self-mutilation' factor, characterized by high levels of hostile traits, novelty seeking, and harm avoidance.

CONCLUSION

The results of the present study suggest that different and overlapping temperamental traits in suicidal and self-mutilating patients are present, although only high levels of PS could predict SA repetition. Finally, HTTLPR may mediate the risk for SMB through modulation of some temperamental traits.

[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.

5-HTTLPR polymorphism in bulimia nervosa: a multiple-model meta-analysis

Several lines of research have found that genes in the serotonergic system may cause susceptibility to eating disorders (EDs). In particular, functional polymorphisms of the serotonin transporter gene (5-HTT) have been suspected to play a role in the pathogenesis of eating disorders. Several studies have examined the association between the 5-HTTLPR polymorphism and bulimia nervosa (BN). The results of these investigations have been unclear. The aims of this meta-analysis were to clarify the association between BN and 5-HTTLPR using statistical models not used by previous meta-analyses, and extend upon previous meta-analyses by including new samples. PsychINFO, ISI, and PubMed databases were searched for studies published up to May 2011. Ultimately, six case-control samples were included. Data were pooled using dominant and additive models. Both models showed a nonsignificant association between the 5-HTTLPR polymorphism and BN. However, this does not detract from recent research suggesting that the 5-HTTLPR polymorphism may be responsible for the phenotypic variability in the psychopathological symptoms observed in patients with BN. Future research should examine the association of BN with 5-HTTLPR using the recently proposed triallelic model.

Monoamine oxidase A gene polymorphism and suicide: an association study and meta-analysis

BACKGROUND

Abnormalities in brain monoamine transmission have been implicated in the pathogenesis of suicidal behavior. Studies examining the association between monoamine oxidase A (MAOA)-uVNTR polymorphism and suicide revealed inconsistent findings. This study aims to evaluate the possible association between the MAOA-uVNTR polymorphism and suicidal behaviors by examining our own subjects and conducting a meta-analytic review.

METHODS

373 unrelated psychiatric patients (including 160 suicide attempters and 213 non-suicide attempters) were genotyped for the MAOA-uVNTR polymorphism. A meta-analysis was then performed by pooling data from seven case-control association studies by random effects model.

RESULTS

Our results indicate that there is no association between the MAOA-uVNTR polymorphism and suicide attempts in both genders. It also reveals that there is no association with violent suicide attempts. In the meta-analysis, there is no association between the polymorphism and suicidal behaviors. Also, there is no difference in the allelic distribution between psychiatric patients with and without suicidal behaviors. Limitations Our study was constrained by the insufficient information about environmental risk factors of suicide.

CONCLUSIONS

Our study is the first one to use meta-analysis in exploring the role of the MAOA-uVNTR polymorphism in suicidal behavior in psychiatric patients. No significant association was found in our study, suggesting MAOA-uVNTR polymorphism is unlikely to contribute significantly to suicide behavior. Further studies investigating the gene-environment interaction or focusing on the genetic risk factors of endophenotypes of suicidal behaviors are warranted.