While early studies with first generation TSPO PET tracers, for example [11C](R)-(1-[2-chrorophynyl]-N-methyl-N-[1-methylpropyl]-3 isoquinoline carboxamide (11C-(R)-PK11195) showed increased TSPO binding (91, 92), more recent studies did not find signs of microglial activation using the PK11195 tracer (93), and the specificity of TSPO binding to assess the inflammation associated with schizophrenia has been challenged (94). Here, TSPO is linked to schizophrenia.