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Highlights d Three groups of highly genetically-related disorders among 8 psychiatric disorders d Identified 109 pleiotropic loci affecting more than one disorder d Pleiotropic genes show heightened expression beginning in 2 nd prenatal trimester d Pleiotropic genes play prominent roles in neurodevelopmental processes Authors Cross-Disorder Group of the Psychiatric Genomics Consortium

Objective To conduct a genome-wide association study (GWAS) of anorexia nervosa and to calculate genetic correlations with a series of psychiatric, educational, and metabolic phenotypes. Method Following uniform quality control and imputation using the 1000 Genomes Project (phase 3) in 12 case-control cohorts comprising 3,495 anorexia nervosa cases and 10,982 controls, we performed standard association analysis followed by a meta-analysis across cohorts. Linkage disequilibrium score regression (LDSC) was used to calculate genome-wide common variant heritability [ hSNP2, partitioned heritability, and genetic correlations (rg)] between anorexia nervosa and other phenotypes. Results Results were obtained for 10,641,224 single nucleotide polymorphisms (SNPs) and insertion-deletion variants with minor allele frequency > 1% and imputation quality scores > 0.6. The hSNP2 of anorexia nervosa was 0.20 (SE=0.02), suggesting that a substantial fraction of the twin-based heritability arises from common genetic variation. We identified one genome-wide significant locus on chromosome 12 (rs4622308, p=4.3×10−9) in a region harboring a previously reported type 1 diabetes and autoimmune disorder locus. Significant positive genetic correlations were observed between anorexia nervosa and schizophrenia, neuroticism, educational attainment, and high density lipoprotein (HDL) cholesterol, and significant negative genetic correlations between anorexia nervosa and body mass index, insulin, glucose, and lipid phenotypes. Conclusions Anorexia nervosa is a complex heritable phenotype for which we have found the first genome-wide significant locus. Anorexia nervosa also has large and significant genetic correlations with both psychiatric phenotypes and metabolic traits. Our results encourage a reconceptualization of this frequently lethal disorder as one with both psychiatric and metabolic etiology.

Internet-based guided self-help for bulimia nervosa was not superior compared with bibliotherapy, the gold standard of self-help. Improvements remain stable in the long term.

Interventions for main carers of adult patients with anorexia nervosa (AN) can reduce the caregiving burden and increase caregiver skills. However, the effectiveness and feasibility for carers of adolescent patients, the optimal form of the intervention and long-term outcomes are largely unknown. We evaluated the efficacy and feasibility of the “Supporting Carers of Children and Adolescents with Eating Disorders in Austria” (SUCCEAT) workshop vs. online intervention. Main caregivers (parents) of adolescent patients with AN were randomly allocated to a workshop (n = 50) or online version (n = 50). Participants were compared to a non-randomised comparison group (n = 49) receiving multi-family or systemic family therapy. Primary (General Health Questionnaire) and secondary outcomes were obtained at baseline, three-month and 12-month follow-up. Adherence was high for workshop and online participants (6.2 and 6.7 sessions completed out of 8). Intention-to-treat analyses revealed significant pre–post reductions in the primary outcome for the workshop (d = 0.87 (95%conficence interval (CI): 0.48; 1.26)) and online (d = 0.65 (95%CI: 0.31; 0.98)) intervention that were sustained at the 12-month follow-up. There was no significant group difference (p = 0.473). Parental psychopathology and burden decreased and caregiver skills increased in all groups; the improvement of caregiver skills was significantly higher in SUCCEAT participants than in the comparison group. Online interventions for parents of adolescents with AN were equally effective as workshops. The improvements remained stable over time.