Nightmare sufferers show atypical emotional semantic associations and prolonged REM sleep-dependent emotional priming

•Nightmare (NM) sufferers have uncommon emotional semantic associations.•Rapid eye movement (REM) naps lead to restricted breadth of associations for primed negative cue words.•REM naps lead to increased breadth of associations for primed positive cue words.•After 1 week, the healthy control (CTL) group no longer showed altered semantic access for primed words.•NM sufferers retain their priming effect at the 1-week retest.