Bipolar kids may have body clock problem

INDIANAPOLIS, Nov. 12 (UPI) -- U.S. researchers link malfunctioning circadian clock genes to bipolar disorder in children.

The study, involving 152 children with the condition and 140 control children, found four versions of the regulatory gene RORB associated with pediatric bipolar disorder.

RORB is mainly expressed in the eye, pineal gland and brain. Its expression is known to change as a function of circadian rhythm in some tissues, and mice without the gene exhibit circadian rhythm abnormalities.

"Our findings suggest that clock genes in general and RORB in particular may be important candidates for further investigation in the search for the molecular basis of bipolar disorder," study leader Alexander Niculescu from Indiana University School of Medicine in Indianapolis said in a statement.

Niculescu said pediatric bipolar disorder is characterized by alternating bouts of depression and mania in children, but it does not affect all young people in the same way and its duration and severity can vary enormously.

The study was published in BMC Psychiatry.