The association between eveningness and autistic traits: Mediating effects of depression and insomnia.

There is a lack of research on the relationships between autistic traits and morningness-eveningness. The current research explored associations between autistic traits (preferences for routine, difficulties with imagination, difficulties with social skills, fixations with numbers and patterns, and difficulties with attention switching) and morningness-eveningness, including the component of Morning Affect (alertness/energy upon awakening). The potential mediation effects of depression and insomnia were also tested. 163 adults (university students and general population) completed an online survey including questionnaire measures of autistic traits, morningness-eveningness, depression, and insomnia. Positive correlations were found between most autistic trait subcomponents, depression, and insomnia. The autistic trait of difficulties in attention switching was correlated with more eveningness and with less Morning Affect, but significant correlations were not observed with any other autistic trait. Depression mediated the relationship between eveningness and difficulties in attention switching. Although insomnia alone was not a significant mediator, when combined with depression in a serial mediator model, a significant mediation effect was shown. The current results suggest that greater eveningness may be related with the autistic trait of difficulties in attention switching possibly through the mechanism of increased insomnia and elevated risk for depression. These findings may potentially inform interventions.