阈下抑郁个体对负性情绪刺激的注意解脱困难

本研究拟采用点探测范式及不同情绪内容的面孔刺激（高兴、中性、悲伤和愤怒）考察阈下抑郁个体的负性注意偏向及其内在机制。点探测任务中情绪面孔配对呈现（负性-中性、正性-中性），配对面孔中的情绪线索位置与靶刺激的位置构成负性一致/不一致和正性一致/不一致条件，同时实验中加入“中性-中性”面孔线索作为一致和不一致条件的对比基线来考察注意偏向的内在机制。结果发现，阈下抑郁个体在负性不一致条件下的反应时显著长于负性一致条件，表明阈下抑郁个体具有对负性刺激的注意偏向；进一步比较发现，阈下抑郁个体在负性不一致条件下的反应时显著的长于“中性-中性”基线条件，而负性一致条件与基线之间差异不显著，表明阈下抑郁个体的负性注意偏向为对负性刺激的注意解脱困难。结果另发现，阈下抑郁个体未能像无抑郁对照组个体表现出对正性刺激的注意偏向。结果表明，处于阈下抑郁状态的个体表现出对负性刺激的注意偏向，具体为对负性刺激的注意解脱困难，其原因可能是由于阈下抑郁个体在注意控制和情绪调节功能上的紊乱。

Difficulty in Disengaging Attention from Emotionally Negative Stimuli among Individuals with Sub-threshold Depression

Sub-threshold depression is clinically classified as those with mild self-reported symptoms of depression, but do not meet the criteria for major depression disorders. Given that people with sub-threshold depression are more likely to develop major depression disorders, it is critical to gain a better understanding of this disorder from both clinical and cognitive perspectives. The attentional bias towards negative emotional stimuli has been suggested as a precursor (or predictor) for depression. Using dot probe tasks, previous studies have revealed that, in patients with major depression, the attentional bias towards negative emotional stimuli can be the result of either facilitated orienting towards these stimuli or the difficulty in disengaging from them. No study has yet investigated this attentional bias in individuals suffering from sub-threshold depression. The present study examined the attentional bias towards negative emotional stimuli and the components of attentional bias among individuals with sub-threshold depression using dot probe task. A two-stage screening procedure were used to recruit participants with sub-threshold depression and non-depressed controls. The severity of neuroticism and anxiety were also collected and compared between individuals with sub-threshold depression and non-depressed controls. Positive, neutral and negative facial expression (positive: happy faces; neutral: neutral faces; negative: sad and angry faces) were selected from the NimStim Face Stimulus Set to create positive-neutral and negative-neutral pairs. Moreover, Neutral-Neutral baseline condition was included to explore any observed attentional bias effects that due to facilitated orienting or delayed disengagement of attention.Results found no significant differences between individuals with sub-threshold depression and non-depressed controls in age and general intelligence. However, individuals with sub-threshold depression had increased anxiety, neuroticism and depression than non-depressed controls. Behavioral data found that individuals with sub-threshold depression expressed significantly longer reaction time in negative-incongruent condition when compared with negative-congruent condition, indicating individuals with sub-threshold depression showed attentional bias for negative stimuli. To differentiate the components of attentional bias, we compared negative-congruent and negative-incongruent condition with the neutral-neutral baseline condition. Results observed that individuals with sub-threshold depression expressed longer reaction time in negative-incongruent condition than in neutral-neutral baseline condition, whereas no significant difference between negative-congruent condition and neutral-neutral baseline. These findings suggested that attentional bias for negative stimuli reflects difficulty in disengaging attention from negative stimuli among individuals with sub-threshold depression. In addition, we also found that non-depressed controls showed significantly longer reaction time in positive-incongruent condition compared with positive-congruent condition, suggesting non-depressed controls expressed attentional bias for positive stimuli. No other significant results were found.Conclusion, attentional bias for negative stimuli were observed among individuals with sub-threshold depression and the attentional bias for negative stimuli reflect difficulty in disengaging attention from emotionally negative stimuli. Individuals with sub-threshold depression did not express attentional bias towards positive stimuli as non-depressed controls did. The dysfunction of attentional control and emotional regulation may underlying attentional bias for negative stimuli among individuals with sub-threshold depression.