bars, respectively. doi:10.1371/journal.pone.0125569.g001 represent a selection bias. This said, we believe these data could represent a useful, although preliminary, insight into a neglected topic, namely the use of AAs as augmentation agents in AN. Still, in line with the exploratory aim of this work, to the best of the authors’ knowledge, only very little data is currently available on the use of aripiprazole in AN. 8 / 12 Atypical Antipsychotics in Anorexia Nervosa The relevance of clinical judgment has been also recently highlighted and in this study, per clinical decision, those with a greater number of weekly binge-purging episodes were found to have been started with aripiprazole. This choice was made by our group in light of the hunger-neutrality of this medication; therefore, it was most often used in order to avoid exacerbating binge-purging behaviors. In contrast, those with severe physical hyperactivity were started with olanzapine because of its beneficial effects on anxiety, agitation, and aggressiveness also due to its sedative properties. Given the greater number of weekly binge-purging episodes in the ARI group when compared to OLA, it is unwise to draw firm conclusions on the effectiveness of aripiprazole in reducing binge-purging episodes. Although intriguing, future studies on PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19786681 a more homogeneous sample are warranted to shed light on this issue. Differently from what initially hypothesized, BMI significantly increased at discharge with no differences amongst groups. Although olanzapine-induced weight gain in AN has been MedChemExpress 345627-80-7 questioned, such a compound has been found to play a role in this regard. However, since the three groups had comparable BMI upon admittance, the lack of differences amongst groups is of interest and highlights the role of the multimodal approach adopted during hospitalization instead of the relevance of medications per se. The main finding of this work is represented by the positive effects with large effect size we found with the adjunct of aripiprazole to antidepressants on eating-related obsessive-compulsive symptomatology. Notwithstanding comparable baseline scores, the ARI group showed a significantly more marked improvement on YBC-EDS global score and both subscales when compared to the others. Obsessive-compulsive traits are frequently intertwined with AN since they not only characterize the course of illness but also tend to predate its onset. Still, the lifetime prevalence of OCD is elevated in AN. Moreover, this improvement PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19785045 is of interest since it has been found that obsessive-compulsive traits adversely affect outcome and it is in line with what Trunko and collaborators described in their case report. In fact, the latter group described how aripiprazole contributed to improve several psychopathological aspects of AN and comorbid conditions like depression and generalized anxiety. Another interesting element is that obsessions have been recently related to purging behaviors in AN and we consistently found aripiprazole as effective on both aspects. Speculating on the potential mechanisms by which this medication might be effective is way beyond the scope of this paper. Nevertheless, it could be raised the hypothesis that its partial agonist action might be of some 
utility in modulating dopamine levels which are strictly related to anxiety in AN. Also, it is not even possible to ascertain whether such an improvement is related to anxious/depressive comorbidity or to the effect of aripiprazol
