Background: Deng, Li and Tang (2014) reported that depression symptom severity is negatively associated with dispositional mindfulness and importantly, positively associated with zone-outs (mind-wandering without meta-awareness). We replicated and extended their study by exploring possible explanations for these relationships, and by also investigating whether mind-wandering is related to (1) trait rumination subtype—brooding, depressive or reflective, and (2) trauma intrusions—a hallmark PTSD symptom, since both rumination and trauma intrusions strongly correlate with depression. We also explored if dispositional mindfulness—the opposing construct of mind-wandering—mediated these relationships. Method: Two hundred participants completed mindfulness tendency and depression severity measures, counterbalanced with the Sustained Attention to Response Task (SART)—including thought probes to index behavioral mind-wandering (target-error frequency), subjective mind-wandering and meta-awareness—then the rumination style and trauma intrusion frequency measures. Results: Depression scores positively correlated with mind-wandering with and without meta-awareness and with SART target-error rates, and negatively correlated with dispositional mindfulness. Further, trait brooding positively correlated with mind-wandering without meta-awareness. Dispositional mindfulness mediated the relationships between brooding and depression, and depression and mind-wandering, and also negatively correlated with trauma intrusion frequency. Limitations: Limitations include measurement and mind-wandering definitions, and an inability to make causal claims. Conclusions: People experiencing greater depression symptomology, and/or who have a greater tendency to brood, mind-wandered more often. Further, people who experience more trauma intrusions tend to be less mindful. These results point to potential harmful effects of mind-wandering through people's reduced propensity to be mindful, facilitating a negative self-referenced cognitive loop that may maintain or increase depression.
- Trauma intrusions