CLOCK and delirium: Circadian gating of cognition involves modulation of cellular excitability and synaptic plasticity, although the exact molecular mechanisms remain elusive.[14, 15, 16] Nevertheless, several signaling pathways and proteins (e.g., cAMP, PKA, ERK, and GSK3) have been identified to be implicated in the clock shaping of cognitive capacity.[17, 18, 19] Cognitive impairment is a core feature of serious mental disorders (e.g., delirium and Alzheimer's disease), and also displays time‐of‐day variations.