Assertiveness, insomnia and depression: which relationship?

Introduction: Some empirical data and clinical observation suggest that people with chronic insomnia have difficulties in assertiveness. However, the literature on this relationship is very poor. Some studies show that low assertiveness is linked to higher severity of depression. Additionally, several studies support the role of insomnia in predicting the onset of depression. The aim of this exploratory cross-sectional study is to evaluate if assertiveness predicts depression directly and/or indirectly through the mediation of insomnia. Materials and methods: The sample consisted of 374 young university students aged 19e35 years (M1⁄4 20.87 ± 2.02), of whom 75.4% were fe- male. Participants completed different self report questionnaires: the Insomnia Severity Index (ISI); the Beck Depression Inventory-II (BDI-II); the Scale for Interpersonal Behavior (SIB) which allow to distinguish Assertive performance and Distress of assertiveness. Questionnaires were administered in group at the end of academic lessons.Results: Participants were classified according to their insomnia severity into Subclinical Insomnia (SI): ISI < 111⁄4 304 and Clinical Insomnia (CI): ISI > 11 1⁄4 66. Results of one-way ANOVAs evidenced that the CI group reported higher scores in the Distress of assertiveness scale (M 1⁄4 66.38 ± 15.54) compared to the SI group (M 1⁄4 58.03 ± 16.25; F(1,368) 1⁄4 14.54, p < .001). They also reported less scores in the Assertive performance subscale, despite this difference was only marginally significant (F(1,367) 1⁄4 3.09, p1⁄4 .08). A significant difference emerged in the BDI-II scores (F(1,288) 1⁄4 50.86, p < .001): the CI group reported higher level of depression (M 1⁄4 16.18 ± 9.50) compared to the SI group (M 1⁄4 8.33 ± 7.02). The rela- tionship between assertiveness, insomnia and depression were also explored using two mediation models in which the scores of Distress and Performance of the SIB were inserted as independent variable, ISI score ad mediator and BDI-II score as dependent variable. The first model showed that Distress of assertiveness predicts directly (b1⁄4 .34, p < .001) and indirectly (b1⁄4 .24, p1⁄4 .001 and b1⁄4 .42, p < .001) depression severity, through the median of insomnia (indirect effect: b1⁄4 .10 [95% bootstrapped CI: 0.05e0.16]). The second model showed that Assertive performance (b1⁄4 .11, p1⁄4 .029) and Insomnia (b1⁄4 .49, p< .001) predict directly and independently depression severity. The indirect effect in the second mediation model was not significant. Conclusions: Results suggest that the distress associated to assertive or non assertive behaviors predicts the severity of depressive symptoms both directly and indirectly, through the mediation of insomnia. Conversely, behaving assertively (Assertive performance) may have protective effects and reduce depression severity. If confirmed through longitudinal data, these results may have an impact on clinical practice, suggesting the importance of including training to improve assertiveness in the treatment of patients with depression and insomnia.