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Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
Replicable differences in preferred circadian phase between bipolar disorder patients and control individuals
Joel Wood1, Boris Birmaher, David Axelson
1Departments of Psychiatry and Human Genetics, University of Pittsburgh School of Medicine and Graduate School of Public Health, Western Psychiatric Institute and Clinic, Pittsburgh, PA, United States.
Psychiatry Research
|March 13, 2009
Summary
Bipolar disorder (BP) cases are more likely to be evening types, indicating a circadian phase delay. This finding was consistent across bipolar I and II disorder subtypes and linked to depressive mood states.
Area of Science:
- Chronobiology
- Psychiatry
- Sleep Medicine
Background:
- Morningness/eveningness (M/E), a measure of circadian phase preference, has been linked to bipolar disorder (BP). Prior studies suggested BP cases are more evening-oriented, but lacked systematic controls and clinical variable assessment.
- Understanding the relationship between circadian rhythm and mood disorders is crucial for developing targeted therapeutic strategies.
Purpose of the Study:
- To replicate and validate the association between M/E preference and bipolar disorder in a large, well-defined sample.
- To investigate potential confounding factors, including medication use and depressive symptom severity, on the M/E-BP relationship.
- To assess the stability of M/E preference over time in individuals with bipolar disorder.
Main Methods:
- A comparative study design involving 190 adults with bipolar disorder (BP) and 128 community-based controls.
- Assessment of M/E preference using the Composite Scale of Morningness (CSM).
- Statistical analyses to account for potential confounders such as age, medication, and depressive mood scores.
Main Results:
- Bipolar disorder cases exhibited significantly lower CSM scores, indicating a more evening-type preference compared to controls, even after adjusting for confounding variables.
- No significant differences in M/E scores were observed between bipolar I (BP1) and bipolar II (BP2) disorder subtypes.
- CSM scores demonstrated stability over a 2-year period in a subset of participants.
- Medication use (anxiolytics, antidepressants, antipsychotics, mood stabilizers, stimulants) and elevated depressive mood scores were associated with lower CSM scores.
Conclusions:
- The findings confirm a replicable association between bipolar disorder and evening-type circadian preference, suggesting a potential circadian phase delay in BP.
- Circadian rhythm disturbances, specifically phase delay, may play a significant role in the pathophysiology of bipolar disorder.
- The results highlight the intricate link between circadian phase, mood states, and medication in individuals with bipolar disorder.
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