Nicotine consumption and schizotypy in first-degree relatives of individuals with schizophrenia and non-psychiatric controls.

Individuals with schizophrenia have very high rates of cigarette smoking, and much has been discovered about the influence of nicotine on brain functioning in schizophrenia. However, less is understood about the relationship between nicotine consumption and milder phenotypes related to schizophrenia, specifically schizotypy. This study examined the relationship between nicotine consumption and schizotypy in two unmedicated samples that included first-degree relatives and non-psychiatric controls. Forty-two first-degree relatives and 50 control participants were administered a self-report questionnaire on schizotypal features as well as a self-report questionnaire on smoking behavior. A positive relationship was found between smoking status and level of schizotypy, and higher levels of schizotypy significantly predicted the odds of being a smoker after controlling for gender and group status. Interestingly, group status was a significant moderator in the relationship between level of schizotypy and smoking status, such that the relationship between these two variables was only significant in the first-degree relatives. This is the first study to investigate the relationship between these variables in a sample of first-degree relatives of individuals with schizophrenia. Those individuals with more schizotypal features are presumably at greater risk for schizophrenia-spectrum disorders and thus may be more likely to smoke cigarettes given the known biochemical effects of nicotine on overt positive and negative symptoms of schizophrenia. Although relatives did not differ from controls in their level of self-reported schizotypy, the significant relationship between smoking status and schizotypy in the former group is likely explained by their genetic vulnerability to schizophrenia-spectrum disorders.