Propranolol treatment of traumatic memories in adults with post-traumatic symptoms: A randomized controlled trial in an outpatient setting

Background and objectives Re-experiencing traumatic events is common and often accompanied by emotional distress. While propranolol has been proposed as a treatment for traumatic memories based on reconsolidation theory, evidence remains mixed. This randomized controlled trial aimed to determine the effectiveness of brief propranolol treatment on participants with traumatic memories and associated symptoms (not necessarily meeting diagnostic criteria for PTSD). Methods A double-blind, placebo-controlled randomized trial was conducted in an outpatient setting in a Midwestern Canadian city. Seventy-five participants (propranolol: n=38; placebo: n=37) were assessed at baseline, 4 weeks, and 8 weeks post-intervention. Propranolol was administered following memory reactivation, in keeping with reconsolidation theory; the implications of this timing are discussed. Participants completed primary outcome measures including the Clinician-Administered PTSD Scale (CAPS), Impact of Event Scale-Revised (IES-R), and Traumatic Memory Description Measure (TMDM), alongside clinical interviews assessing anxiety, depression, and traumatic memory experiences. Results No significant differences emerged between groups on primary outcome measures assessing traumatic memories and their consequences. However, anxiety, distress, and trauma-related symptoms decreased two-fold over time across both groups. Clinician and self-ratings of improvement were statistically higher in the propranolol group compared to placebo. The treatment group demonstrated perfect adherence, which was representatively higher than the placebo group. Conclusion Propranolol did not differ significantly from placebo on primary outcome measures of traumatic memory and associated symptom severity. Both groups showed clinically meaningful within-group reductions over time. Subjective global improvement ratings were higher in the propranolol group, though these secondary findings should be interpreted cautiously. The results do not support propranolol as an efficacious treatment for traumatic memories but highlight the potential therapeutic value of memory reactivation procedures and warrant further controlled investigation. The timing of propranolol administration in relation to memory reactivation, specifically post-reactivation in the current protocol, may be a critical limiting factor.