TSPO and schizophrenia: Studies using newer tracers have shown predominantly null results (Bloomfield et al., 2016; Coughlin et al., 2016; Hafizi et al., 2016; Kenk et al., 2015; Ottoy et al., 2018; Takano et al., 2010) with one study (Collste et al., 2017) showing reduced TSPO in individuals with schizophrenia-spectrum diagnoses.