Bipolar disorder, like most psychiatric disorders, is characterized by the frequency and severity of its symptoms. Many people may exhibit characteristics of the disorder without meeting the criteria for a diagnosis, meaning they may be more likely to develop the disorder at some point.
Now, a study conducted by Ben Bullock and Greg Murray of the Swinburne University of Technology and published in Clinical Psychological Science reveals that one factor — instability in circadian rhythm — is one particularly strong predictor of vulnerability for bipolar disorder.
The researchers had over 350 participants complete a questionnaire intended to reveal vulnerability to bipolar disorder. Afterwards, the researchers then gave the top and bottom 10% — those most likely and those least likely to develop the disorder — a small wristband that would record their sleep/wake cycle and movement 24 hours a day for a week.
As predicted, the researchers found that the individuals in the top 10% were significantly more likely to show unstable sleep/wake cycles than individuals who were in the bottom 10%.
These new findings may help to inform the development of new therapeutic interventions for at-risk populations — strengthening and stabilizing activity rhythms may be one way to protect against bipolar, for instance.
Bullock, B., & Murray, G. (2013). Reduced Amplitude of the 24-hr Activity Rhythm: A Biomarker of Vulnerability to Bipolar Disorder? Clinical Psychological Science. DOI: 10.1177/2167702613490158