Memory surfacing among veterans with PTSD receiving hyperbaric oxygen therapy

Introduction: Growing evidence demonstrates that hyperbaric oxygen therapy (HBO2) induces neuroplasticity and can benefit individuals with post-traumatic stress disorder (PTSD). The aim of the current study was to evaluate the rate and pattern of memory surfacing during the course of HBO2 among veterans with combat-related PTSD. Methods: In a post-hoc analysis of a prospective study of the effect of HBO2 on PTSD symptoms in veterans, we evaluated the rate and character of memory surfacing during the course of HBO2 treatment. The treatment consisted of 60 daily 90-minute sessions, at 2 atmospheres absolute (ATA) pressure and 100% oxygen. Results: For 10 (35.7%) of the 28 participants, surfacing of new memories was reported during the HBO2 treatment course. Memories surfaced mainly during the second month of the treatment, at the mean session of 30.5 +/- 13.2. For 9 of these 10 participants, prodromal symptoms such as distress, anxiety, or worsening depression were documented; and in four, somatic pain was reported prior to memory surfacing. The pain and distress of memory surfacing resolved over the course of one to 10 days. Discussion: Among individuals with PTSD, the surfacing of new memories, accompanied by emotional distress and somatic pain, is common during HBO2. The surfacing of memories sheds light on the biological effect of HBO2 on the brain sequela of PTSD. It is highly important that in treating patients for any indication, HBO2 medical teams be aware and capable of addressing memory surfacing, particularly in those with a history of trauma.