Painful emotional memories may not be permanent, according to researchers from the University of Montreal. Manipulating hormone levels can decrease the recall and reconsolidation of negative memories.

Memories are continuously retrieved and reactivated, which keeps the memories alive. Researchers have shown that glucocorticoids, such as cortisol, modulate this process. Glucocorticoids are released in response to stress and affect memory retrieval; they are also important in the formation of new memories. Lowering cortisol levels before memory recall has long-lasting effects, according to the current study, published in the Journal of Clinical Endocrinology and Metabolism.

The study included 33 male young adults who listened to a story that contained emotionally neutral and negative events. Three days later, the men were divided into three groups: one group received 750 mg of metyrapone, a drug that inhibits cortisol secretion, one group received 1500 mg of metyrapone, and one group received a placebo. The men were then asked to remember the story. Four days later, all the men were asked to remember the story again, when cortisol levels were normal in all groups.

The researchers were surprised to report that the men who received the double-dose of metyrapone demonstrated impaired recall of the negative parts of the story, but no impairment in recalling the neutral parts. The impairment continued 4 days later. The continued decrease of negative memories indicates a neural change, and not just a drug-induced lapse, that may allow the brain to eventually erase and write over bad memories.

These results strengthen previous work that has revealed a potentially therapeutic role of glucocorticoids in the treatment of anxiety disorders, post traumatic stress disorder, and phobias. While some of the studies have produced conflicting results, the association between glucocorticoid levels and memory is clear. The authors of the current study hope that pharmacological therapy can be combined with psychotherapy to reduce the emotional suffering caused by negative memories. Glucocorticoids may also have a role in preventing negative memories from forming in the first place.

The current study needs to be replicated in a larger and more diverse population. Gender likely plays a role in hormone –induced memory retrieval, and the findings need to be confirmed among females. Also, the men in the study were healthy. Evaluating memory retrieval in traumatized individuals may show different results. Last, metyrapone, the cortisol inhibitor used in the study, is not commercially available anymore. Other drugs have similar effects on glucocorticoid levels, and studies with these compounds would clarify the role of hormones in memory recall.

Memories are a way to hold on to things you love. When memories keep reliving traumatic negative events, the effects can be devastating to the health and quality of life of an individual. Mitigating the harmful effects of painful memories will have long-lasting benefits to individuals affected by numerous anxiety and mental health conditions.

References

de Quervain DJ (2008). Glucocorticoid-induced reduction of traumatic memories: implications for the treatment of PTSD. Progress in brain research, 167, 239-47 PMID: 18037019

de Quervain DJ, & Margraf J (2008). Glucocorticoids for the treatment of post-traumatic stress disorder and phobias: a novel therapeutic approach. European journal of pharmacology, 583 (2-3), 365-71 PMID: 18275950

Het S, Ramlow G, & Wolf OT (2005). A meta-analytic review of the effects of acute cortisol administration on human memory. Psychoneuroendocrinology, 30 (8), 771-84 PMID: 15919583

Marin MF, Hupbach A, Maheu FS, Nader K, & Lupien SJ (2011). Metyrapone Administration Reduces the Strength of an Emotional Memory Trace in a Long-Lasting Manner. The Journal of clinical endocrinology and metabolism PMID: 21593118

Marin MF, Pilgrim K, & Lupien SJ (2010). Modulatory effects of stress on reactivated emotional memories. Psychoneuroendocrinology, 35 (9), 1388-96 PMID: 20471179

Schelling G, Roozendaal B, & De Quervain DJ (2004). Can posttraumatic stress disorder be prevented with glucocorticoids? Annals of the New York Academy of Sciences, 1032, 158-66 PMID: 15677403

Tollenaar MS, Elzinga BM, Spinhoven P, & Everaerd WA (2008). The effects of cortisol increase on long-term memory retrieval during and after acute psychosocial stress. Acta psychologica, 127 (3), 542-52 PMID: 18155678

Wolf OT (2009). Stress and memory in humans: twelve years of progress? Brain research, 1293, 142-54 PMID: 19376098

Wolf OT, Kuhlmann S, Buss C, Hellhammer DH, & Kirschbaum C (2004). Cortisol and memory retrieval in humans: influence of emotional valence. Annals of the New York Academy of Sciences, 1032, 195-7 PMID: 15677409