Several genes with an essential role in the regulation of eating behavior and body weight are considered candidates involved in the etiology of eating disorders (ED), but no relevant susceptibility genes with a major effect on anorexia nervosa (AN) or bulimia nervosa (BN) have been identified. Brain-derived neurotrophic factor (BDNF) has been implicated in the regulation of food intake and body weight in rodents. We previously reported a strong association of the Met66 allele of the Val66Met BDNF variant with restricting AN (ANR) and low minimum body mass index in Spanish patients. Another single nucleotide polymorphism located in the promoter region of the BDNF gene (−270C>T) showed lack of association with any ED phenotype. In order to replicate these findings in a larger sample, we performed a case–control study in 1142 Caucasian patients with ED consecutively recruited in six different centers from five European countries (France, Germany, Italy, Spain and UK) participating in the ‘Factors in Healthy Eating’ project. We have found that the Met66 variant is strongly associated to all ED subtypes (AN, ANR, binge-eating/purging AN and BN), and that the −270C BDNF variant has an effect on BN and late age at onset of weight loss. These are the first two variants associated with the pathophysiology of ED in different populations and support a role for BDNF in the susceptibility to aberrant eating behaviors.

The aim of this study was to evaluate which clinical variables might influence the antiobsessional response to proserotonergic drugs in a sample of patients with obsessive-compulsive disorder (OCD). One hundred fifty-nine patients with DSM-IV OCD underwent a 12-week standardized treatment with fluvoxamine, clomipramine, citalopram, or paroxetine. According to treatment response, defined as a reduction of the Yale-Brown Obsessive Compulsive Scale total score >35%, patients were divided into two groups. Ninety patients (56.6%) responded to treatment and 69 (43.4%) did not. Responders had a significantly higher frequency of positive family history for OCD (FH-OCD) in their first-degree relatives, whereas nonresponders had an earlier onset and a higher frequency of “poor insight” subtype and somatic obsessions. The predictive value of all these variables was tested by a stepwise logistic regression analysis that confirmed poor insight and FH-OCD to be the best predictors of poor and good drug treatment response, respectively. These preliminary findings need additional investigations toward a better definition of the genetic and biological heterogeneity of patients with OCD, and they underlie the importance of collecting the insight score and family history for psychiatric disorders in the pretreatment assessment.

Eating disorders (ED), such as anorexia nervosa (AN) and bulimia nervosa (BN), are complex psychiatric disorders where different genetic and environmental factors are involved. Several lines of evidence support that brain-derived neurotrophic factor (BDNF) plays an essential role in eating behaviour and that alterations on this neurotrophic system participates in the susceptibility to both AN and BN. Accordingly, intraventricular administration of BDNF in rats determines food starvation and body weight loss, while BDNF or its specific receptor NTRK2 knockout mice develop obesity and hyperphagia. Case–control studies also suggest a BDNF contribution in the aetiology of ED: we have previously reported a strong association between the Met66 variant within the BDNF gene, restricting AN (ANR) and minimum body mass index (minBMI) in a Spanish sample, and a positive association between the Val66Met and −270C/T BDNF SNPs and ED in six different European populations. To replicate these results, avoiding population stratification effects, we recruited 453 ED trios from eight European centres and performed a family-based association study. Both haplotype relative risk (HRR) and haplotype-based haplotype relative risk (HHRR) methods showed a positive association between the Met66 allele and ANR. Consistently, we also observed an effect of the Met66 variant on low minBMI and a preferential transmission of the −270C/Met66 haplotype to the affected ANR offspring. These results support the involvement of BDNF in eating behaviour and further suggest its participation in the genetic susceptibility to ED, mainly ANR and low minBMI.