You may already know that the body’s circadian rhythm determines sleep and eating patterns, but there’s also evidence that it plays a role in the expression of bipolar disorder symptoms. A new study from McLean Hospital (affiliated with the Harvard Medical School) suggests that circadian rhythm is a key factor in the alteration of certain chemicals that are associated with the regulation of depression and anxiety.
What is Circadian Rhythm?
When most people think of circadian rhythm, they think of our sleep cycles. For example, when we travel to a different time zone, most of us recognize that our body’s internal clock (our circadian rhythm) doesn’t automatically adjust to the new time zone, and we experience jet lag. However, sleep isn’t the only process regulated by our circadian rhythm.
The term ‘circadian rhythm’ actually refers to an approximately 24-hour cycle of physiological processes, including brain wave activity, cell regeneration, hormone production, and other biological activities. Our circadian rhythm depends in part on genes and natural factors within the body, but it also responds to light and darkness in our environment.
Circadian Rhythm Cycle
Image Source: www.nih.gov
How Circadian Rhythm Might Affect Mental Health
The study from McLean Hospital presents new evidence that certain brain chemicals depend on the body’s circadian rhythm to function properly, and that these chemicals directly affect the parts of the brain associated with bipolar disorder. Researchers performed post-mortem examinations on the brains of 15 patients with bipolar disorder, 12 patients with schizophrenia, and 12 control patients and found that the brains of patients with bipolar disorder and schizophrenia had decreased somatostatin immunoreactive neurons as a result of altered circadian rhythm.
Somatostatin is a neurotransmitter that is associated with the regulation of anxiety and depression, and abnormal cycles of somatostatin have been linked to depression and anxiety disorders, including bipolar disorder. Abnormal cycles of this neurotransmitter could lead to both manic symptoms (such as feelings of euphoria, irritability, difficulty sleeping, risky behavior) and depressive symptoms (including low energy, feelings of emptiness, changes in appetite, and suicidal thoughts) associated with bipolar disorder.
Hope for New Treatment Options
Now that a link between circadian rhythm and bipolar disorder has been identified, researchers are hopeful that new treatment options will soon be available. Dr. Harry Pantazopoulos, a neuroscientist at McLean Hospital and one of the study’s authors, says bright light therapy could be one option. Because circadian rhythm responds to light and dark, bright light therapy treatment could correct abnormalities in circadian rhythm in some parts of the brain, thus reducing bipolar disorder symptoms. Additionally, circadian rhythm treatment medications, like Rozerem, could help reduce bipolar disorder symptoms also.