Active contextualization reduces traumatic memory intrusions via memory integration

Intrusion, the involuntary retrieval of unwanted and often traumatic memories, can significantly impact mental health and even lead to post-traumatic stress disorder (PTSD) when mishandled. Cognitive theories propose that the origin of intrusion lies in the overactivation of sensory memory being disintegrated from the corresponding contextual memory, highlighting the crucial associations between memory contextualization and intrusion. To test this hypothesis, our study investigated whether enhancing memory contextualization following a traumatic experience could effectively reduce intrusion. Employing the traumatic film paradigm to induce analog trauma, we trained healthy participants in two contextualization approaches: actively retrieving and restructuring film content (active contextualization, AC) or passively restudying content-matched pre-contextualized information (passive contextualization, PC). Diary recordings over the subsequent week revealed a significant reduction in intrusion frequency in the AC group compared to both a no-intervention control group and the PC group. Notably, comparisons between the AC and PC groups, along with analyses of the explicitly recollected and implicitly intruding memories, identified the critical element of the contextualization intervention as the memory transformation and integration induced by active memory retrieval and restructuring. Furthermore, by demonstrating the superiority of AC over a well-established working memory dual-task in reducing intrusions, we confirmed the efficacy of our AC intervention. In conclusion, our findings suggest that contextualization causally diminishes intrusions, providing novel insights into the regulation of the contextual memory system in intrusion intervention. This contribution advances ongoing theoretical development and implies potential clinical applications.