J Psychiatry Neurosci 2013; 38(4): 222-231
Michelle H. Lonergan, BA; Lening A. Olivera-Figueroa, PsyD; Roger K. Pitman, MD; Alain Brunet, PhD
Lonergan, Brunet — Department of Psychiatry, McGill University, and Douglas Mental Health University Institute, Montréal, Que., Canada; Olivera-Figueroa — Department of Psychiatry, Yale School of Medicine, and US Department of Veterans Affairs, West Haven, Conn., USA; Pitman — Department of Psychiatry, Harvard Medical School, Charlestown, Mass., USA.
Background: Considering the pivotal role of negative emotional experiences in the development and persistence of mental disorders, interfering with the consolidation/reconsolidation of such experiences would open the door to a novel treatment approach in psychiatry. We conducted a meta-analysis on the experimental evidence regarding the capacity of the β-blocker propranolol to block the consolidation/ reconsolidation of emotional memories in healthy adults.
Methods: Selected studies consisted of randomized, double-blind experiments assessing long-term memory for emotional material in healthy adults and involved at least 1 propranolol and 1 placebo condition. We searched PsycInfo, PubMed, Web of Science, Cochrane Central, PILOTS, Google Scholar and clinicaltrials.org for eligible studies from the period 1995–2012. Ten consolidation (n = 259) and 8 reconsolidation (n = 308) experiments met the inclusion criteria. We calculated effect sizes (Hedges g) using a random effects model.
Results: Compared with placebo, propranolol given before memory consolidation reduced subsequent recall for negatively valenced stories, pictures and word lists (Hedges g = 0.44, 95% confidence interval [CI] 0.14–0.74). Propranolol before reconsolidation also reduced subsequent recall for negatively valenced emotional words and the expression of cue-elicited fear responses (Hedges g = 0.56, 95% CI 0.13–1.00).
Limitations: Limitations include the moderate number of studies examining the influence of propranolol on emotional memory consolidation and reconsolidation in healthy adults and the fact that most samples consisted entirely of young adults, which may limit the ecological validity of results.
Conclusion: Propranolol shows promise in reducing subsequent memory for new or recalled emotional material in healthy adults. However, future studies will need to investigate whether more powerful idiosyncratic emotional memories can also be weakened and whether this weakening can bring about long-lasting symptomatic relief in clinical populations, such as patients with posttraumatic stress or other event-related disorders.
An earlier version of this work was presented at the 12th European Conference on Traumatic Stress in Vienna, Austria, June 2–5, 2011.
Submitted June 7, 2012; Revised Sept. 18, 27, 2012; Accepted Oct. 1, 2012.
Acknowledgements: A. Brunet holds a salary award from the Fonds de Recherche du Québec – Santé. M.H. Lonergan holds a student award from the Canadian Institutes of Health Research. L.A. Olivera- Figueroa holds a postdoctoral fellowship from the Fernand-Seguin Research Centre.
Competing interests: None declared.
Contributors: All authors contributed to study design, wrote and reviewed the article and approved its publication. M.H. Lonergan, L.A. Olivera-Figueroa and A. Brunet acquired the data, which M.H. Lonergan, R.K. Pitman and A. Brunet analyzed.
Correspondence to: A. Brunet, Douglas Mental Health University Institute, 6875 blvd. LaSalle, Montréal QC H4H 1R3; firstname.lastname@example.org