HCN1 and schizophrenia: Among the genes associated with decreased vagal modulation of heart rhythm and decreased HRV in patients with schizophrenia, we can note HCN1 (Hyperpolarization-Activated Cyclic Nucleotide Gated Potassium Channel 1), CACNA1C (Calcium Voltage-Gated Channel Subunit Alpha1 C), and KCNH2 (Potassium Voltage-Gated Channel Subfamily H Member 2) [66,67].