Our ability to “suppress” memories is quite useful. This prevents us from ruminating on painful moments, and can help us move forward. However, sleep deprivation reduces our ability to do so. In a recent paper in Trends in Cognitive Science, they put forward a model that links sleep deprivation with weakened control over our unwanted memories and emotions.

The researchers suggest that when we do not sleep, the right dorsolateral-prefrontal cortex (an area associated with self-control, memory, and attention) cannot properly block unwanted thoughts. This makes it difficult for us to suppress our negative memories, and can even make them pop up more frequently. This is corroborated by another recent study, in which sleep-deprived participants were also unable to “control” their memories. Not only were these participants unable to block them out, but they would often re-experience these thoughts frequently.

It appears that lack of sleep also makes us worse at controlling how our memories affect our emotions. In the same study, participants were shown images that could trigger negative feelings. Well-rested participants were not only able to suppress the memory of seeing negative images, but also reported less negative feelings when seeing these images compared to participants who were kept awake all night.

Taken together, this model suggests a link between sleep deprivation, memory and emotion control. Without sleep, many of the cognitive processes of the brain cannot function properly, potentially leading to a cycle of worsening psychological symptoms. For example, a person who has experienced a traumatic event could develop post-traumatic stress disorder (PTSD) and insomnia, worsening their recurring thoughts, which could lead to reduced sleep quality and more unwanted feelings. The researchers even suggest that this model might apply to other disorders that are characterized by unwanted, recurring thoughts, such as depression, obsessive-compulsive disorder, and schizophrenia.