Investigation of the mediating role of risk-taking behavior, reward sensitivity, and cyclothymic/irritable temperament in the relationship between bipolar disorder symptoms and chronotype

This study examined the mediating roles of reward sensitivity, risk-taking behavior, and cyclothymic/irritable temperament in the relationship between bipolar disorder (BD) risk and chronotype in a healthy population. The study included 244 individuals (61.1% (n=149) female), aged 18–24, who were university students in Turkey without a diagnosis of BD or any other psychiatric disorder and who voluntarily agreed to participate. Data were collected in two phases: face-to-face and online. Participants first completed the Effort Expenditure for Rewards Task and the Modified Balloon Analogue Risk Task via computer, followed by the Morningness-Eveningness Questionnaire, the Mood Disorder Questionnaire (MDQ), the cyclothymic and irritable subscales of the TEMPS-A Temperament Scale, the Behavioral Inhibition System/Behavioral Activation System Scale, and the Short Form of the BARRATT Impulsiveness Scale. The mean age of participants was 21.23±1.59. Examination of chronotype distribution revealed that 27 participants (11.1%) were morning-type, 152 (62.3%) were intermediate-type, and 65 (26.6%) were evening-type. No significant relationship was found between chronotype and BD risk as measured by the MDQ (r=-0.025, p>0.05). No significant difference was found in BD risk as measured by the MDQ between chronotype groups (F=0.373, p=0.689). As impulsivity levels increased, BD risk as measured by the MDQ also increased (r=0.350, p<0.001). Additionally, a significant and positive correlation was found between irritable temperament and BD risk as measured by the MDQ (r=0.149, p=0.018). In conclusion, no relationship was identified between chronotype and BD risk as measured by the MDQ. However, factors such as irritable temperament and impulsivity were observed to be significantly associated with BD risk as measured by the MDQ. This finding may be attributed to the fact that the sample consisted of healthy individuals who did not exhibit clinical levels of BD symptoms. These findings indicate the need for further research to better understand the relationship between chronotype and BD risk, as well as to identify psychological and behavioral factors associated with BD vulnerability.