Inflexible autonomic responses to sadness predict habitual and real-world rumination: A multi-level, multi-wave study.

Inflexibility of the autonomic nervous system is relevant to depression vulnerability, but the downstream behavioral consequences of autonomic inflexibility are not well understood. Rumination, a perseverative thinking style that characterizes depression, is one candidate phenotype relevant to autonomic inflexibility. Undergraduates (N = 134) completed a sadness induction while respiratory sinus arrhythmia was measured, and completed four waves of follow-up over twelve weeks during which rumination, stressful events, and symptoms of depression were measured. Individuals with less autonomic flexibility had higher levels of trait rumination, and were more likely to ruminate in daily life, regardless of stress exposure, whereas individuals with more autonomic flexibility ruminated more only in the context of stress. These findings provide the first evidence that autonomic inflexibility may confer vulnerability to context-insensitive rumination. This work suggests a potential behavioral mechanism by which autonomic inflexibility leads to problems with self-regulation and depression, suggesting multiple avenues for intervention to target these markers of vulnerability.