BackgroundCurrent interventions for obsessive-compulsive disorder (OCD) are often of limited benefit. Aim:To evaluate the effect of adjunctive treatment with EEG biofeedback training on the symptoms and cognitive functioning of individuals with OCD. AimTo evaluate the effect of adjunctive treatment with EEG biofeedback training on the symptoms and cognitive functioning of individuals with OCD. MethodsA total of 79 individuals with OCD were randomly assigned to the study group (n=40) or the control group (n=39). The control group was treated using a combination of sertraline (50 to 200 mg/d) and weekly cognitive behavioral therapy sessions by trained therapists for 8 weeks; the study group was treated using the same regimen plus EEG biofeedback sessions 5 times per week. The Yale Brown Obsessive Compulsive Scale (YBOCS) was administered by a psychiatrist who was blind to patients’ treatment status before treatment and at the end of the 2nd, 4th, 6th and 8th week for treatment; the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was administered before and after the 8-week trial.ResultsThree individuals dropped out of the study group and four dropped out of the control group (χ2=0.186, p=0.712). At the end of the study, treatment was considered effective in 32 of the 37 (86.5%) participants in the study group and in 22 of the 35 (62.9%) participants in the control group (χ2=5.36, p=0.021). Repeated measures analysis of variance showed that the improvement in OCD symptoms was greater in the study group than the control group by the 6th week of treatment. At the end of the trial all 5 cognitive dimensions assessed by the RBANS were significantly better in study groups subjects than in control group subjects and the changes in the YBOCS score were significantly correlated with changes in the RBANS overall score in the study group (r=0.43, p=0.007), but not in the control group (r=0.171, p=0.327).ConclusionsThis methodologically rigorous study demonstrates that 8 weeks of adjunctive treatment with EEG biofeedback training can significantly improve the clinical symptoms and cognitive functioning of OCD patients being treated with medication and psychotherapy. Further work is needed to assess the long-term effects of biofeedback training and the need for booster sessions after an initial period of training.