Bad Memories Don’t Have to Last Forever

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.

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