Understanding reward motivation and expectancy in early phase psychosis smokers: a neuroimaging and genetic approach

Psychotic disorders, such as schizophrenia, are severe mental illnesses affecting approximately 3% of the population. These disorders typically begin in late adolescence or early adulthood and are often associated with lifelong, psychological and social impairments. Smoking rates are highly elevated in these disorders; 75-85% of patients smoke, compared to approximately 20% of the general population. Individuals with psychotic disorders also have extremely low smoking-cessation rates even though they can be motivated and persistent in their attempts. The purpose of this study will be to further understand motivations for smoking and the brain mechanisms underlying tobacco craving and expectancy in patients with psychotic disorders. By manipulating visual smoking-related cues, the effects on specific brain pathways (e.g., the reward pathway) will be examined. Given the diversity in characteristics of people with these disorders, we will also attempt to gain a better appreciation for the effects of different genes on patients' sensitivity to smoking-related cues. Methods: Smokers (patients and controls) will be exposed to smoking and neutral videos while the researchers perform a brain scan. Activation in relevant brain regions of will be examined while varying the subjects' perceived drug availability. Patients' experience of smoking cravings will also be assessed. Additionally, clinical assessment of patients' smoking patterns and reasons for smoking will be collected. A saliva DNA collection method will allow for analyses of the genes of interest to determine whether patients with certain genetic profiles show particular brain responses suggesting sensitivity to reward, when they are exposed to smoking videos. The proposed study has the potential to uncover brain, genetic, and psychological explanations for the high rates of tobacco use and dependence in people with psychotic disorders.