Since 1980, criteria for diagnosing bipolar disorder in adults have also been used to diagnose mania in children, with some modifications to adjust for age.

Diagnosis and Treatment of Bipolar Disorder in Children and Adolescents

At this time, both patients and professionals seem to have an unprecedented interest in circadian rhythms.  We now know that the body's clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus, and that the SCN regulates the pineal gland's secretion of the hormone melatonin.

Psychiatric Times Vol 13 No 5