Morning affect, eveningness, and amplitude distinctness: associations with negative emotionality, including the mediating roles of sleep quality, personality, and metacognitive beliefs.

Eveningness has been associated with maladaptive behavior, poor sleep quality, and psychological disorder. However, while much research has utilized unidimensional measures of morningness-eveningness, the current study aimed to test associations between negative emotionality (depression, anxiety, and stress/DAS) and the circadian rhythm components of morning affect/alertness, eveningness, and amplitude of diurnal variation (distinctness). Associations with maladaptive metacognitive beliefs, neuroticism, conscientiousness, and sleep quality were also investigated, and possible indirect (mediation) effects between the circadian rhythm components and negative emotionality were explored. A sample of 625 Chinese university students (aged 18-33, mean = 19.78; 189 males) completed validated questionnaire measures in an online survey. Morning affect was positively correlated with conscientiousness, and negatively correlated with neuroticism, poor sleep quality, and aspects of maladaptive metacognitive belief (including belief in the uncontrollability and danger of thoughts). Distinctness generally showed the opposite associations. DAS was negatively correlated with morning affect, and positively correlated with eveningness and distinctness. However, after controlling for morning affect the correlations with eveningness were near zero. With either morning affect or distinctness as the predictor for negative emotionality (combined DAS scores), significant indirect effects were found through neuroticism, sleep disturbances, and belief in the uncontrollability and danger of thoughts. These results are consistent with other recent findings that indicate morning affect/alertness, and a stronger amplitude of diurnal variation, may both be more strongly related to negative emotionality than is eveningness preference. They also highlight that these relationships may involve associations with aspects of personality, sleep quality, and also maladaptive metacognitive beliefs. Further research is needed to establish the directions of possible causal relationships, which may help to inform interventions for psychological distress and disorder.