PER1 and schizophrenia: In schizophrenia (SCH), clock gene disruption has been demonstrated for CRY1 and PER2 in skin fibroblasts, PER1/2/3 and NPAS2 in white blood cells, and in post-mortem analyses for PER1/2, CRY2, and NR1D1 in the prefrontal cortex [11–13].