Effect of Systemic Inflammation on Emotion and Cognition in Patients With Mood Disorder - A Vaccine Study

Study design: In this double blind randomized crossover design, each participant will receive saline injection or typhoid vaccine injection at the first study visit, and will then receive the other injection at the second study visit. All participants will undergo study procedures (clinical and imaging) in two separate sessions after each injection given at least 7 days apart (within 10-14 days). Baseline blood samples will be taken and vital signs will be measured. Participants will be asked to complete the mood questionnaires and computerized reward tasks. Then, injections of normal saline will be administered intramuscularly in the deltoid muscle. At 1.5h, 3h, 4h and 6h after the injection, the subjects will complete the mood questionnaires and vital signs will be assessed. The computer based task will be repeated at 3h. Between3h and 6h after the injection blood samples will be collected for cytokines measurement. At 4h, a structural magnetic resonance imaging (MRI), and Functional magnetic resonance imaging (fMRI) will be done. Follow up visits/calls with the patients will be set to check their physical and mood status.