Furthermore, impairments in the four major clock genes (Clock, Per, Cry and Bmal1) were found for bipolar disorder, depression-related disorders, autism spectrum disorder, and impairments in some of these major clock genes were also reported for schizophrenia (Clock, Per and Cry), anxiety disorder (Cry) and attention deficit hyperactivity disorder (Clock). Here, BMAL1 is linked to attention deficit-hyperactivity disorder.