Brain Circuits in Schizophrenia and Smoking

Objective The health risk associated with tobacco use is high, and is even higher in people with severe mental illness. The underlying brain circuitry for smoking-mental illness comorbidity is unknown. Identifying brain comorbidity circuitry is important for new therapeutic development. This study will examine whether a specific brain circuitry can explain the high rate of smoking in patients with schizophrenia. Identifying the key brain circuits associated with smoking, especially smoking in a high risk population, will provide concrete biomarkers for new therapeutic development, and ultimately reducing the smoking related health burden. Study Population Schizophrenic patients and their family members, non-schizophrenia controls and their family members, including smokers and nonsmokers in each of the four groups will be included in this study. Design 1. A cross-sectional study for all subjects at baseline. They will receive clinical and diagnostic interviews, functional, symptom, and cognitive testing, and MRI. They will also have blood drawn, to identify brain circuits and covariates associated with the severe smoking problem in schizophrenia. 2. A prospective longitudinal study design where smokers will be encouraged to quit smoking and smoking cessation support is provided if needed, followed by retesting of imaging and some clinical assessments, to identify brain circuits associated smoking cessation or the difficulty of quitting in schizophrenia and non-schizophrenia smokers. Outcome Measures Combining event-related and resting fMRI techniques, we propose to test the hypothesis that an abnormal dorsal anterior cingulate cortex (dACC) and ventral striatum (VS) circuit underlies the high prevalence of comorbid smoking in schizophrenia. We also propose to test specific clinical implications of this circuit including a within-subject event-related fMRI study to test the mechanistic implication of the rsFC signals, a prospective follow-up to test the circuit s predictive validity on smoking behavior change, and genetic studies to describe the path from genes to brain circuits to smoking behaviors.