Odour cueing during sleep augments trauma-focused psychotherapy

Trauma-focused psychotherapies reduce posttraumatic stress disorder (PTSD) symptoms by updating maladaptive traumatic memories into more adaptive representations. However, many patients do not achieve clinically meaningful improvement, highlighting the need for augmentation strategies. Targeted memory reactivation (TMR), in which memory cues are re-presented during sleep to strengthen memory consolidation, is a promising approach. We combined a mechanistic study in healthy participants with a randomized clinical trial to test whether odour cueing during sleep augments trauma-focused psychotherapy. In healthy participants, re-exposure to the therapy-associated odour during sleep increased slow-wave activity and slow oscillations, while greater increases in slow oscillation–spindle coupling were associated with reduced emotional arousal during recall of aversive autobiographical memories. In patients with PTSD, repeated odour cueing during sleep throughout 12 weeks of trauma-focused treatment improved clinician-rated and self-reported PTSD symptoms, particularly re-experiencing and negative alterations in cognition and mood, and accelerated treatment response and remission. These findings provide converging mechanistic and clinical evidence that TMR can enhance trauma-focused psychotherapy, potentially through sleep-dependent memory consolidation.