Abstract: Background: There is lack of data regarding BDNF serum levels in patients with obsessive–compulsive disorder (OCD). The aims of the present study were: 1) to assess the serum BDNF content in a sample of drug-naïve patients with OCD and 2) to assess whether putative alterations in peripheral BDNF may be associated to OCD severity and clinical characteristics.Methods: Twenty-four drug-naïve patients with a principal diagnosis of OCD were recruited. In parallel, a control group of 24...