SENSO

Major Depressive Disorder (MDD) is a highly prevalent disorder. The diagnosis of MDD is usually based on clinical interview with collection of symptoms affecting cognition, emotion and behavior. In order to improve early diagnosis and to define homogeneous group of patients better suited for treatment, we clearly need diagnosis of mental disorders based upon pathophysiologic processes. Genetic and environmental factors influence the onset, maintenance and longitudinal course of MDD. Among these environmental factors, interpersonal stress and life-events involving social rejection may precipitate depressive episodes. MDD is also associated with disengagement from professional and vocational commitments. This suggests MDD has tight links with social functioning. Moreover it has recently been emphasized that social cognition is a good predictor of functional and social outcome of depressed patients. Neurobiological mechanisms of social difficulties of depressed patients are unknown. The main objectives of SENSO are to define social related biomarkers of MDD. SENSO will specifically focus on social inclusion and exclusion and other forms of social-psychological threats to define related biomarkers for early diagnosis and follow-up of patients with MDD. This project uses a multidisciplinary approach combining brain imaging, immunological, virtual reality and cognitive experiments to study the biological bases of social impairment in MDD. SENSO will bring expertise from cognitive-social psychology, cognitive neuroscience, immunology and clinical psychiatry to define new pathophysiologic pathways. Our main hypothesis is that depressed patients showed heightened sensitivity to social signal reflecting impairment in basic social processes that monitor social acceptance. The project will include 60 depressed patients and 150 healthy controls. Patients and controls will be simultaneously examined with multiple experimental tasks. The project is composed of 5 workpackages that evaluate behavior, cognitive, biological and neural biomarkers of sensitivity to social signal in MDD. Throughout the project patients and controls will participate to experimental tasks assessing sensitivity to dynamic social signal, social attention, sensitivity to criticism or approbation from others, social exclusion and abilities to socially reconnect after exclusion. Cognitive performance, EEG and functional MRI, behavior and relationships between pro-inflammatory cytokines and social stress will be systematically assessed in depressed patients and controls. Our multitasking approach will provide the opportunity for a better definition of phenotypes of MDD associated with social impairment. Additional possible output of the project also includes the development of specific devices and tools for cognitive and social remediation. Overall this project contributes to the development of personalized medicine tailored to the specific needs of patients suffering from major depression.