Evidence of shared genetic factors between nicotine dependence and schizophrenia would imply a common etiology between the two disorders. There is new evidence that polygenic risk scores for nicotine dependence and related phenotypes predict schizophrenia, and that polygenic risk scores for schizophrenia predict nicotine dependence and related phenotypes (Chen et al., 2016). However, additional studies are needed to clarify this relationship.
