How a good night's sleep may help us restrict bad memories

Our brains have an ‘in-built’ ability to restrict intrusive memories, which contributes to the maintenance of our mental health.

• However, a new study from the University of York and the University of East Anglia in the United Kingdom now suggests that disrupted sleep and sleep loss interferes with that ability, making intrusive memories more persistent.
• This could contribute to a range of mental health conditions, such as anxiety, depression, and even post-traumatic stress disorder (PTSD).
• The study also suggests that rapid-eye movement (REM) sleep, where dreaming occurs, may be crucial to the ‘housekeeping’ of the brain by maintaining the ability to keep unwanted memories and thoughts at bay.

It is becoming increasingly obvious that sleep plays a range of crucial roles in helping our bodies maintain various aspects of health, including brain health and mental health.

A new study from the Universities of York and East Anglia in the United Kingdom — whose findings appear in PNAS — now looks at an even more intriguing aspect of the relationship between sleep, the brain, and mental health.

The study found that disrupted sleep affected the brain’s ability to restrict intrusive memories, which could contribute to conditions including anxiety, depression, and even post-traumatic stress disorder (PTSD).

Study co-author Marcus Harrington, PhD, a lecturer in psychology at the University of East Anglia who specializes in sleep, memory, emotion, and mental health, told GMHCN that he and his colleagues conducted this study because they were keen to find out more about why some people might find it more difficult to overcome traumatic experiences than others.

For this study, the researchers recruited 85 healthy adults ages 18–30 years — of whom 30 were male and the rest female — whom they asked to spend one night in the sleep laboratory. Around half of the cohort (43 participants) had to stay awake all night, while the rest had a healthy night’s sleep.

To see how sleep or the lack thereof might influence the brain’s ability to suppress unwanted memories and thoughts, the researchers had previously asked the participants to undertake an exercise: They had to look at pictures of faces, some of which appeared in the context of negative scenes, such as a car crash.