Lower levels of soluble β-amyloid precursor protein, but not β-amyloid, in the frontal cortex in schizophrenia

•There are lower levels of soluble amyloid precursor protein in Brodmann's area (BA) 6 from people with schizophrenia.•The lower levels of amyloid precursor protein in BA 6 are not restricted to one of two defined sub-groups within the syndrome of schizophrenia.•We show that levels of levels of Aβ1–40 or Aβ1–42 are not changed in Brodmann's area 6 from people with schizophrenia.•Our data in schizophrenia does do not reflect the changes in these markers in the CNS of people with Alzheimer's disease.