Suicidal ideation in a sample with a first-episode of restrictive eating disorders: The role of biomarkers

•We found high rates of suicidal ideation in treatment-naïve first episode restrictive eating disorder patients.•Homocysteine levels were higher among the patients who presented suicidal ideation.•These results show the importance of affective symptoms and their role in the pathogenesis and illness outcome.•Early detection and treatment of these patients could lead to an improvement in their prognosis. This study investigates the associations between the presence of suicidal ideation (SI), depressive symptoms and potential biomarkers in a sample with treatment-naïve first episode restrictive eating disorder The observational study included 77 patients and 53 controls matched by age and socioeconomic status. We used the Beck Depressive Inventory focusing particularly on item 9, which measure the severity of SI. We found high rates of SI (40.8%) and depression (52.9%). Serum ​​levels of homocysteine were significantly higher among patients who reported SI compared with patients without SI (t = 2.47; p = .016; d = 0.595). Greater depressive symptoms were significantly correlated to lower levels of vitamin B12 (t = 2.08; p = .041; d = -0.504) and folic acid (U = 403.5; p = .015; d = -0.039). Serum levels of homocysteine were inversely correlated to those of vitamin B12 ​​(rho = -0.310; p