(1) Main aim: The effect of neurofeedback with pharmacotherapy on cognitive ability and executive function in patients with obsessive – compulsive disorder, Goals: A- Comparison between the efficacy of Neurofeedback and Pharmacotherapy group, and placebo Neurofeedback and Pharmacotherapy group, and Pharmacotherapy group on cognitive abilities and executive functions in patients with obsessive-compulsive disorder. (2) Design: This study is a randomized single blind clinical controlled trial. (3) Setting and conduct: Study population consisted of patients with obsessive-compulsive disorder are referred to hospital in Hamadan farshchian that 45 person divided in 3 groups included Neurofeedback with Pharmacotherapy, placebo Neurofeedback and Pharmacotherapy, Pharmacotherapy alone will be randomly selected. Inclusion criteria: Diagnosis of obsessive-compulsive disorder based on the psychiatrist's interview According to DSM-5 criteria, receiving sertraline, Be at least 18 and up to 60 years, A minimum score of 16 on the Yale Brown Obsessive Compulsive Scale. Exclusion criteria: The people with acute and serious other mental disorders, the types of dementia and cognitive disabilities. Intervention and time: Group 1- In this group patient will receive Neurofeedback 2 times per week for 10 weeks and they also will receive sertraline 20-40 mg for 16 weeks. Group 2- placebo Neurofeedback 2 times per week for 10 weeks and they also will receive sertraline 20-40 mg for 16 weeks. Group 3- Receiving sertraline 10 mg for 16 weeks. All patients before and after the treatments will assess by Yale Brown Obsessive Compulsive Scale, CGI scale, Wisconsin, Stroop and Pasat tests. Outcome variables: Obsessive-compulsive gdisorders, cognitive abilities and executive functions.