Daily Associations of Sleep Quality and Sleep Duration with Anxiety in Young Adults: The Moderating Effect of Alexithymia

The present study examined the daily, within-individual associations of anxiety with sleep quality and sleep duration and the moderating effects of alexithymia on these associations in community-dwelling young adults. It was hypothesized that daily anxiety and sleep parameters would be bidirectionally related and alexithymia would moderate these relationships.Participants completed morning and evening diaries assessing daily anxiety and sleep parameters for 30 consecutive days. They also completed questionnaires assessing baseline sleep parameters, anxiety, and alexithymia. Multilevel modeling was used to evaluate the within-individual associations between daily anxiety and sleep parameters and whether between-individual differences in alexithymia moderated these associations.Higher anxiety relative to personal averages across the study period was associated with shorter sleep duration at night. Poorer sleep quality and shorter sleep duration relative to personal averages were associated with higher next-day anxiety. A significantly stronger association between poorer sleep quality and higher next-day anxiety was observed in individuals with higher levels of alexithymia.Daily anxiety and sleep quantity are bidirectionally associated within individuals in community-dwelling young adults. Poorer sleep quality was associated with higher next-day anxiety but not vice versa. Individuals with higher levels of alexithymia might be more vulnerable to the effects of poor sleep on next-day anxiety.