Strength of excitation and insomnia as mediated by mood dimensions.

Background: The main goal of our study was to demonstrate the relationship between the strength of excitation (SE) as one of the basic central nervous system (CNS) properties and insomnia, and to determine the role of the mood components as mediators of this relationship. We hypothesized that SE directly and indirectly via arousal-related mood dimensions may be related to insomnia.

Participants and procedure: The study involved 149 people, 85 women and 64 men, aged 18 to 60 (M = 30.11, SD = 11.43) selected from the general population using snowball sampling. The basic properties of the CNS were diagnosed using Pavlovian Temperament Survey. Mood was assessed using the Polish adaptation of UWIST Mood Adjective Checklist. To evaluate insomnia symptoms Athens Insomnia Scale in its Polish adaptation was used.

Results: SE negatively correlated with insomnia (no significant correlations between strength of inhibition and mobility and insomnia). All CNS properties positively correlated with hedonic tone (HT) and energetic arousal (EA), and negatively with tense arousal (TA) as mood dimensions. HT and EA were negatively correlated with insomnia but TA positively correlated with insomnia. Both EA and TA served as mediators in the relationship between SE and insomnia.

Conclusions: The results indicated the relationship between SE and insomnia as well as between SE and EA and TA as mood dimensions related to arousal. Mediation analysis suggests that both EA and TA may serve as mediators of the relationship between SE and insomnia. However, the results of the mediation analysis require careful interpretation.