Affective temperament, impulsivity and biological rhythms in bipolar disorder: A case-sibling-control study

Area of Science:

• Psychiatry
• Neuroscience
• Sleep Medicine

Background:

• Bipolar disorder (BD) is characterized by mood instability and often involves sleep disturbances.
• Affective temperaments and impulsivity are recognized as potential contributing factors to BD pathophysiology.
• Understanding the interplay between temperament, impulsivity, and sleep rhythm is crucial for effective BD management.

Purpose of the Study:

• To investigate the associations between affective temperaments, impulsivity, and sleep-related biological rhythm disturbances in patients with bipolar disorder (BD), their unaffected siblings, and healthy controls.
• To explore the mediating role of impulsivity in the relationship between specific temperaments and sleep disturbances.
• To identify potential therapeutic targets for sleep rhythm regulation in BD.

Main Methods:

• Cross-sectional study involving 82 patients with BD type I, 57 siblings, and 70 healthy controls.
• Utilized the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A), Barratt Impulsiveness Scale (BIS-11), and Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN).
• Employed group comparisons, correlation, hierarchical regression, and mediation analyses.

Main Results:

• Patients with BD exhibited higher depressive, cyclothymic, irritable, and anxious temperaments compared to siblings and controls.
• BD patients showed significantly greater sleep-related rhythm disturbances and higher impulsivity, particularly attentional impulsivity.
• Impulsivity fully mediated the link between irritable temperament and sleep disturbances, and partially mediated the effect of anxious temperament.

Conclusions:

• Anxious and irritable temperaments are associated with sleep-related rhythm disturbances in BD, with impulsivity acting as a significant mediator.
• Hyperthymic temperament demonstrated an inverse relationship with impulsivity and rhythm disturbances.
• Impulsivity emerges as a potential therapeutic target for interventions aimed at improving sleep rhythm regulation in bipolar disorder.