Chronotype in bipolar disorder: an 18-month prospective study

Area of Science:

• Psychiatry
• Chronobiology
• Bipolar Disorder Research

Background:

• Circadian rhythm dysregulation is implicated in mood disorders.
• Evening chronotype is prevalent in bipolar disorder (BD) patients.
• Previous studies on chronotype and BD prognosis have yielded inconclusive results.

Purpose of the Study:

• To investigate the relationship between chronotype and prognostic factors in patients with bipolar disorder (BD).
• To determine if chronotype influences mood episodes and overall prognosis in BD.

Main Methods:

• 80 euthymic BD patients completed baseline questionnaires assessing demographics, anxiety, functioning, and chronotype using the Morningness-Eveningness Questionnaire.
• Patients were monitored monthly for 18 months to track mood episodes and hospitalizations.

Main Results:

• Evening chronotype was associated with higher rates of obesity/overweight, increased anxiety, and more mood episodes in BD patients.
• No significant association was found between evening chronotype and psychiatric hospitalizations.
• A trend towards depressive episodes was observed in the evening chronotype group, but not (hypo)manic episodes.

Conclusions:

• Evening chronotype is a predictor of poor prognosis in bipolar disorder (BD).
• Treating circadian rhythm disruptions, even during euthymia, is crucial for improving patient quality of life and preventing future mood episodes.