Interestingly, although the suprachiasmatic nucleus (SCN) of the hypothalamus constitutes the master organizer of the body’s molecular circadian rhythm, clock genes are also expressed in other regions of the brain, including those relevant to the pathophysiology of depression, such as the amygdala and the hippocampus (Lamont et al. 2005; Jilg et al. 2010; Li et al. 2013; Savalli et al. 2014). Here, CLOCK is linked to depressive disorder.