Circadian rhythm disturbances overlap between psychotic disorders, e.g. schizophrenia, and major depression. We hypothesized that circadian gene variants previously associated with unipolar depression would be overrepresented also in patients with psychotic disorder. Six genetic polymorphisms in ARNTL, PER2 and CRY2 were genotyped in 566 schizophrenia spectrum disorder patients and 926 controls. The rs2290036-C variant of ARNTL was over-represented in psychosis patients, and the variants rs934945-G and rs10462023-G of PER2 were associated with a more severe psychotic disorder. The directions of these genetic associations were in line with those previously identified for depression.
Keywords: ARNTL; CRY2; PER2; circadian; psychosis; severity.