We used positron emission tomography (PET) with the selective H3R radioligand [11C]MK-8278 to measure H3R availability, and employed a task during functional magnetic resonance imaging (fMRI) to assess working memory-evoked brain activation and cognitive task performance, in patients with schizophrenia (n = 12) and matched healthy volunteers (n = 12). This evidence concerns the gene HRH3 and schizophrenia.