Impaired emotional memory dissipation in insomnia disorder.
Level 3 - non-randomized controlled study
Prospective non-randomized comparative cohort study with healthy controls
PubMed 40888367 · doi:10.1017/S0033291725101566
What was done
Researchers measured electroencephalographic (EEG) activity during emotional memory encoding, post-encoding sleep, and three retrieval phases (immediate post-encoding, post-sleep, and 7-day delay) in 34 participants with insomnia disorder and 35 healthy controls. They assessed changes in memory retention, subjective emotional ratings, stability of neural representations, and the predictive value of slow-wave sleep (SWS) and rapid eye movement (REM) sleep durations.
What was found
Healthy controls showed adaptive dissipation of emotional memories, marked by declining memory and reduced subjective negative affect over time. Participants with insomnia demonstrated impaired dissipation, retaining emotional content and affective tone with attenuated time-dependent declines, alongside persistently stable neural representations of emotion. Furthermore, post-encoding SWS and REM durations predicted adaptive memory dissipation in healthy controls but not in participants with insomnia. No exact numerical values, effect sizes, or p-values were reported in the abstract.
Why it matters
The findings demonstrate a breakdown in the normal sleep-dependent decay of emotional memories and their neural signatures in insomnia, highlighting a potential neurobiological mechanism linking chronic sleep disruption to emotional dysregulation.
Limits
The abstract reports purely qualitative/directional findings without specific numerical data, effect sizes, or confidence intervals. The sample size is modest (n = 69 total). The cross-sectional/observational cohort comparison cannot rule out residual confounding, and the long-term clinical implications beyond 7 days were not evaluated.