SYP and major depressive disorder: Multiple aspects of these processes are implicated in the development of anxiety and depression in CCH, including aberrant GABA and glutamate signaling, reduced BDNF, impaired synaptic potentiation, changes in synaptophysin, serotonin, and HCN1, as well as reduced dopamine and KCNQ3 activity [21,22,77,91,102,104,107,108,109,111].