Memories of emotional experiences usually fade over time
Strong memories of stressful experiences occur frequently, but they usually fade away over time. People suffering from anxiety or Post-Traumatic Stress Disorder, however, are affected by terrifying memories that haunt them again and again. It had been shown that the stress hormone cortisol has a strengthening impact on the consolidation of memories, i.e. the several-hour process in the course of which a memory is formed immediately after the experience.
Cortisol influences the reconsolidation of emotional memories
The researchers from Bochum have demonstrated that cortisol effects memories in humans also during the so-called reconsolidation, i.e. the consolidation of memories occurring after memory retrieval. The stress hormone can enhance this process. "The results may explain why certain undesirable memories don't fade, for example in anxiety and PTSD sufferers," says Prof Dr Oliver Wolf. If a person remembering a terrifying event has a high stress hormone level, the memory of that specific event will be strongly reconsolidated after each retrieval.