A multi-method investigation of circadian rhythms, sleep, and affective states: characterising modulation, imaging reward mechanisms, and improving clinical measurement

The current findings advance evidence of a relationship between biological rhythms and reward motivation in humans at multiple biobehavioural levels. This project has psychometrically quantified the separation of biological rhythms and mood leading to the generation and initial psychometric testing of a new self-report measure of sleep quality, diurnal preference, and mood. In addition, this project has found evidence for diurnal variation of reward motivation, a preliminary step in investigating modulation of reward motivation by circadian functioning. Future research should systematically investigate the relationships between the multifaceted construct of reward motivation and the range of processes involved in biological rhythms.