CLOCK and cone-rod synaptic disorder syndrome, congenital nonprogressive: CRSDs have a high rate of comorbidity with various psychiatric disorders, especially mood disorders.5, 6, 7, 8 A previous study showed that approximately half of their patients with N24SWD developed psychiatric problems before or after the onset of N24SWD.7 CRSDs are thought to result from impairment of the circadian clock system and/or a misalignment between the endogenous circadian rhythm and exogenous entrainment factors that affect sleep timing.