| 其他摘要 | Everyone will experience joy and loss in their own lives. The death of a loved one (e.g., a parent, spouse, sibling, or child) is inevitably heart-breaking. Losing a child before adulthood is even worse. There has been a remarkable number of parents who have lost their only child, known as Shidu parents. In Chinese culture, a child is vital for generational continuity and plays an important economic and social support role for parents. Losing an only child means the termination of family lines and the loss of a caregiver during the aging process. Moreover, Chinese culture regards the death of a child as a sign of bad luck, which stigmatizing the parents. Therefore, losing an only child is an enormous risk to the parents' mental status, and Shidu parents often exhibit mental problems, including post-traumatic stress disorder (PTSD). Previous studies showed that PTSD symptoms are most common and serious in Shidu parents. PTSD in Shidu parents is particularly worthy of attention, and it is of great significance to explore suitable intervention programs for these parents.
Study 1 aims to explore the network structure of PTSD symptoms among Shidu parents. A convenient sampling method was used to conduct a questionnaire survey on 385 Shidu parents. PTSD symptoms were measured by the PTSD Checklist for DSM-5 (PCL-5). The results revealed that nightmares (B2), diminished interest (DS), exaggerated startle (E4), and irritability/anger (E1) were the most central symptoms. The strongest connections emerged between the symptoms of recurrent thoughts (B1) and nightmares (B2), irritability/anger (E1) and reckless/self-destructive behavior (E2), hypervigilance (E3) and exaggerated startle (E4), and concentration problems (ES) and sleep problems (E6). It is suggested that these symptoms may be the best intervention targets.
Study 2 aims to explore the internal causes of the key symptoms found in study 1，that is, the attentional bias to emotional stimuli. The characteristics and neural mechanisms of attentional bias and its relationship with PTSD symptoms were explored by using behavioral and neurological research methods. Study 2 contains two sub-studies.
Study 2a aims to investigate the time course of attentional bias among Shidu parents, and to examine its relationship with PTSD symptoms. Bereaved participants (n=38) completed a dot-probe task with negative (trauma-related), positive, and ms), moderate (750 ms), and long (1250 ms). The measurement tool for PTSD symptoms was the same in study 1 .The results showed that participants had difficulty in disengaging from both negative and positive stimuli at moderate stimulus exposures (750 ms) and avoidance of negative stimuli at long stimulus exposures (1250 ms). At long stimulus exposures (1250 ms), attentional avoidance of negative stimuli was positively correlated with PTSD symptoms, including nightmares (B2), psychological cue reactivity (B4), negative emotional state (D4), detachment (D6), reckless/self-destructive behavior (E2). Difficulty in disengaging from positive stimuli was negatively correlated with PTSD symptoms, including nightmares (B2), psychological cue reactivity (B4), detachment (D6), restricted affect (D7), and reckless/self-destructive behavior (E2).
Study 2b aims to explore the mechanism of attentional bias and its relationship with PTSD symptoms. The convenient sampling method was used to select 28 bereaved peoples who lost their only child as the experimental group and 37 general parents as the control group. The attentional bias to emotional stimuli was measured using a dot-probe paradigm (750 ms for stimulus exposure duration), and the activity of the dorsolateral prefrontal cortex (DLPFC) was measured using a near-infrared brain functional imager (fNIRS). The measurement tool of PTSD symptoms was the same in study 1 .The results showed that both Shidu and general parents showed attentional bias toward and difficulty in disengaging from negative and positive stimuli. The left DLPFC activity decrease when Shidu parents showed difficulty in disengaging from negative and positive stimuli, and the right DLPFC activity decrease when general parents showed attentional bias toward positive stimuli and difficulty in disengaging from negative stimuli. The right DLPFC activity when difficulty in disengaging from negative and positive stimuli was negatively correlated with PTSD symptoms in Shidu parents, that is the greater deactivation of right DLPFC, the higher the symptom level,including avoidance of thoughts (C1), negative beliefs (D2), distorted blame (D3), negative emotional state (D4), restricted affect (D7), irritability/anger (E1), hypervigilance (E3), and exaggerated startle (E4).
Based on the results of study 1 and study 2, study 3 used attentional bias training method to intervene PTSD symptoms of Shidu parents, and measured the effects of the intervention on attention bias, PTSD symptoms, and DLPFC activities. A convenient sampling method was used to select 62 bereaved parents who lost their only child, and they were randomly assigned to either attentional bias modification group (ABM), attention control training group (ACT), or attention control geometry-training group (ACG). Participants performed eight biweekly ABM/ACT/ACG sessions for four weeks. Changes in attentional bias, PTSD symptoms, and DLPFC activation were measured at pre, after 3 and 8 times of interventions. Changes in attentional bias and PTSD symptoms were examined a 4-month follow-up. The measurement of DLPFC activity was the same in study 2b, and the measurement tools of attention bias and PTSD symptoms were the same in study 2. The results showed that ABM had immediate intervention effect on attentional bias toward and avoidance of negative and positive stimuli, while ACT and ACG had immediate and long-term (4 months after) intervention effect on attentional bias toward and avoidance of negative and positive stimuli. Enhanced bilateral DLPFC activities were noted for both ACT and ACG conditions, while decreased bilateral DLPFC activities were noted for ABM under showed difficulty in disengaging from negative and positive stimuli. PTSD symptoms decreased following ACT treatment, including recurrent thoughts (B 1)，flashbacks (B3), psychological cue reactivity (B4), physiological cue reactivity (BS), negative beliefs (D2), distorted blame (D3), negative emotional state (D4), hypervigilance (E3), and exaggerated startle (E4), which indicates that the attention control training under emotional conditions has better intervention effects on PTSD symptoms.
This paper explored PTSD symptoms, and their potential causes among Shidu parents. The research route was from specific symptoms to cognitive processes, from cognitive processes to neurological functions, and explored the use of attention bias training to intervene in PTSD symptoms. This paper promotes our understanding of the relationship between attentional bias and its neural mechanisms in the field of trauma and PTSD symptoms, which has important theoretical significance. In addition, this paper is helpful in improving the relationship between cognition and affective disorders, pointing out that attentional bias to emotional stimulation (disengagement difficulties and avoidance) can be used as the treatment target of PTSD symptoms, and attentional control training under emotional conditions can be used as an intervention technique for PTSD symptoms. This provides a scientific basis for effective psychological counseling and intervention guidence for parents who have lost their only child and has important practical significance. |
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