Intrusive re-experiencing is a hallmark of PTSD. The study applies ecological momentary assessment (EMA) of participants' trauma memories (active group) vs. EMA of a neutral memory (control group) to test whether the active intervention can reduce intrusive symptoms severity and overal PTSD symptom severity in general.

Intrusive re-experiencing is a defining burden for many people with PTSD, often disrupting routines and making it hard to participate in care. Intrusion symptoms tend to be resistant to change, even when broader PTSD symptoms improve (Bar-Haim et al., 2021; Levi et al., 2022). This pattern underscores the need for brief, remote approaches tuned to everyday intrusion dynamics.

The study tests a home-based intervention requiring minimal clinician input that aims to reduce intrusive symptoms. Ecological momentary assessment (EMA) offers such an opportunity. Although typically used for data collection, Pollmann et al. (2024) reported preliminary evidence suggesting that two weeks of EMA focused on a traumatic intrusive memory (TR-IM) were followed by reductions in intrusion symptoms, while other symptom clusters remained comparatively unchanged. Pollmann et al. used prompts adapted from the Autobiographical Memory Questionnaire (AMQ; Rubin et al., 2003). However, in the absence of a control condition, it remains uncertain whether the observed change reflects targeted, safe-context activation of the traumatic memory, a general cognitive-distancing effect from repeated ratings regardless of target, or a different process altogether. A further methodological limitation is that EMA completion depended on participants' spontaneous recollection of the TR-IM in the preceding hours. As a result, responses were intermittent and varied across days and individuals, leading to uneven exposure and data gaps.

The present study aims to test the mechanism in question as well as to create a different setting in which all participants answer the questionnaire at each EMA prompt. Adults with PTSD who report active intrusions will be randomized to one of two otherwise identical 10-day EMA protocols: (1) daily AMQ-based prompts that explicitly target a personally identified TR-IM, or (2) the same prompts targeting a neutral, non-intrusive memory. Primary outcomes will be baseline to post-treatment change and baseline to follow-up change on clinician-rated CAPS-5 total score and CAPS-5 Cluster B indices. Secondary outcomes will be self-reported PCL-5 total score and cluster B scores.

Inclusion Criteria:

• Adults aged 18-70
• Posttraumatic stress disorder
• intrusive symptoms.

Exclusion Criteria:

• Psychotic or bipolar disorder
• Heavy use of drugs or alcohol
• Prominent personality disorder
• Significant risk of harm to self or others
• Current trauma-focused treatment
• Reporting intrusions as thoughts only rather than as memories