The autonomic nervous system (ANS) has received much attention as a potential low-cost, peripheral indicator of depression. Despite theoretical support, however, results have been mixed as to whether indices of the ANS reliably index depression. In response, the present study sought to clarify the relation between ANS activity and depression by examining cardiac autonomic balance (CAB) and cardiac autonomic regulation (CAR), two composite indices of the parasympathetic and sympathetic nervous system, within both a stressful and rewarding context. We hypothesized that CAB_Stress, representing the difference between the parasympathetic and sympathetic branches in response to stress, and CAR_Reward, representing the summation of the two branches in response to reward, will be most indicative of depressogenic risk. We examined the parasympathetic (i.e., respiratory sinus arrhythmia) and sympathetic (i.e., pre-ejection period) responses of 97 emerging adults (M_age = 18.93) for a stress (i.e., negative mood induction) and reward (i.e., probabilistic learning) task, as well as their depressive symptoms at baseline, 3-week, and 6-week follow-up. Analyses found partial support for our hypotheses, revealing greater CAR_Reward (i.e., coactivation of both branches) was related to lower depressive symptoms. Further, exploratory analyses examining gender differences found lower CAB_Stress (i.e., sympathetically-oriented response) was predictive of an increasing trajectory of depression, but only among males. Overall, the current study highlights the importance of simultaneously examining both branches of the ANS across various environmental contexts. Research and clinical implications of the current findings are discussed.

自主神经系统 (ANS) 作为一种潜在的低成本、抑郁症的外周指标而备受关注。然而，尽管有理论上的支持，但关于 ANS 指数是否可靠地指示抑郁症的结果喜忧参半。作为回应，本研究试图通过检查心脏自主平衡 (CAB) 和心脏自主调节 (CAR) 这两个副交感神经和交感神经系统的综合指数，在压力和奖励的背景下阐明 ANS 活动与抑郁之间的关系. 我们假设 CAB _Stress代表副交感神经和交感神经分支对压力的反应，以及 CAR _Reward，代表响应奖励的两个分支的总和，将最能表明抑郁风险。我们检查了 97 名新兴成年人（M_年龄 = 18.93）的副交感神经（即呼吸性窦性心律失常）和交感神经（即射血前期）对压力（即消极情绪诱导）和奖励（即概率学习）的反应任务，以及他们在基线、3 周和 6 周随访时的抑郁症状。分析发现部分支持我们的假设，揭示更大的 CAR_奖励（即两个分支的共同激活）与较低的抑郁症状有关。此外，检查性别差异的探索性分析发现 CAB_压力较低（即，以同情为导向的反应）可以预测抑郁症的增加轨迹，但仅限于男性。总体而言，当前的研究强调了在各种环境背景下同时检查 ANS 的两个分支的重要性。讨论了当前发现的研究和临床意义。