Abstract
BACKGROUND: : Attentional bias towards threat is a core mechanism underlying posttraumatic stress disorder (PTSD). Although attention bias modification (ABM) and attention control training (ACT) have been studied for PTSD, randomized controlled trials (RCTs) have reported inconsistent outcomes. Additionally, the nonemotional conditioning effect of ACT remains unvalidated. Shidu parents in China, a uniquely vulnerable group who have lost their only child, often suffer from severe and persistent PTSD, however, no RCT has yet investigated attention-based interventions among them. Thus, this RCT compared the efficacy of ABM, ACT, and attention control geometric training (ACG), which adapts ACT in a nonemotional context, on PTSD symptoms and dorsolateral prefrontal cortex (DLPFC) activity among Shidu parents. METHODS: : Participants were randomly assigned to the ABM (n = 21), ACT (n = 20), and ACG (n = 21) groups and completed eight biweekly sessions of ABM, ACT, and ACG, respectively. Symptoms, including PTSD clusters and anxiety as primary outcomes and PTSD total and depression as secondary outcomes, along with attentional bias were assessed at pre-treatment, mid-treatment, post-treatment, and a four-month follow-up. DLPFC activity was measured using functional near-infrared spectroscopy (fNIRS) at pre-treatment, mid-treatment and post-treatment. RESULTS: : ACT demonstrated significant improvement in intrusion symptoms, with treatment effects sustained at the four-month follow-up. However, other PTSD symptom clusters, as well as anxiety and depression, did not show significant improvement across any of the groups. At the neurocognitive level, ACT showed reduced vigilance toward threat and decrease in bilateral DLPFC activation under the vigilance condition. In contrast, ACG exhibited only a nonsignificant trend toward reduced vigilance to threat, along with reduction in left DLPFC activity under the same condition. ABM showed no significant improvements in either behavioral or neural measures. CONCLUSIONS: : This study provides preliminary evidence that ACT may be a promising intervention for reducing intrusion symptoms and threat vigilance in Shidu parents, potentially through modulating DLPFC activation. These findings highlight the importance of targeting specific PTSD symptom clusters and corresponding neural pathways in future trauma interventions.