Bipolar Disorder Linked To Genes Of Biological Clock
Abnormalities in the genes that control circadian rhythms (rhythms of approximately 24 hours, also called biological clock) contribute to the development of bipolar disorder (manic depression), suggests a study presented at the Eighth International Conference on bipolar disorder. The conference was held in Pittsburgh between June 25-27 of 2009. The symposia, rapid communications, and poster abstracts for the 8th ICBD, published in the journal, "Bipolar Disorders", Volume 11, Supplement 1, 2009.
Finding may lead to development of new treatments for bipolar disorder.
"We found that mice carrying a mutation in one of the key genes of the circadian rhythm, had behavioral profiles that were surprisingly similar to people experiencing a manic episode of bipolar disorder. In addition, treatment with lithium, a drug for mood stabilizer, reduced their normal behavior, "said Colleen A. McClung of the University of Texas who led the study.
Dr. McClung has focused his research on genes that affect circadian rhythms because many people with bipolar disorder exhibit abnormalities in their biological rhythms. Depression and bipolar disorder were associated with significant activity and sleep disturbance. Changes in schedules may trigger those episodes. Variations on several circadian genes are associated with bipolar disorder, depression and seasonal affective disorder (SAD).
The Clock gene mutations, leading to increased activity of the neurotransmitter dopamine in the ventral tegmental area (VTA) are situated int the the mesencephalon (or midbrain).
"Our results indicate a clear role of circadian genes and gene Clock, in particular, in the control of mood, anxiety and behavior related to reward (eg. Substance abuse)," explains Dr. McClung. They should eventually lead to the development of targeted medicines for the treatment of bipolar disorder, said she.
By Armen Hareyan
Materials from Mescape, Psychomedia and Bipolar Disorders Journal are used in this report.