Abstract :
[en] Introduction: Insomnia and depression are prevalent and frequently co-occurring disorders. Their heterogeneous presentations may reflect shared transdiagnostic mechanisms that remain underexplored. To our knowledge, no study has simultaneously examined shifting (flexibly redirecting attention) and focusing (sustaining attention while resisting distractions) as attentional control subdimensions in relation to insomnia and depression, nor tested rumination as a mediator while modelling insomnia and depression as distinct outcomes within a single framework. Accordingly, this study examined the direct and indirect pathways linking attentional control subdimensions, rumination, insomnia and depression. We hypothesized that both shifting and focusing deficits would contribute to insomnia and depression through direct and indirect pathways via rumination.
Method: Structural equation modelling was conducted in a cross-sectional online community sample of 1195 adults completing French-validated self-report measures of attentional control, rumination, insomnia and depression, with age, gender, anxiety and fatigue included as covariates.
Results: The model showed acceptable fit and explained 59%, 59% and 78% of the variance in rumination, insomnia and depression, respectively. Better focusing was directly associated with fewer sleep difficulties and depressive affects, but not with rumination. Conversely, shifting was not directly associated with either outcome, but better shifting was associated with less rumination, which in turn was associated with sleep difficulties and depressive affects, yielding significant indirect effects. Thus, the hypothesized indirect pathway via rumination was supported for shifting only, and the direct pathways for focusing only.
Discussion: Rumination emerged as a key mediator linking shifting deficits to insomnia and depression, while focusing appeared to be associated with both outcomes independently of rumination. Theoretical and methodological explanations for these differential pathways will be discussed. Our findings underscore the heterogeneity of cognitive mechanisms underlying insomnia and depression, aligning with process-based and individualized perspectives in CBT.
