Sleep Deprivation Disrupts Recall of Conditioned Fear Extinction

BACKGROUND: Learned fear is crucial in the development and maintenance of posttraumatic stress disorder and other anxiety disorders, and extinction of learned fear is necessary for response to exposure-based treatments. In humans, research suggests that disrupted sleep impairs consolidation of extinction, though no studies have examined this experimentally using total sleep deprivation. METHODS: Seventy-one healthy control subjects underwent a paradigm to acquire conditioned fear to a visual cue. Twenty-four hours after fear conditioning, participants underwent extinction learning. Twenty-four hours after extinction learning, participants underwent extinction recall. Participants were randomized to three groups: 1) well rested throughout testing (normal sleep; n = 21); 2) 36 hours' total sleep deprivation before extinction learning (pre-extinction deprivation; n = 25); or 3) 36 hours' total sleep deprivation after extinction learning and before extinction recall (post-extinction deprivation; n = 25). The groups were compared on blink electromyography reactivity to the condition stimulus during extinction learning and recall. RESULTS: There were no differences among the three groups during extinction learning. During extinction recall, the pre-extinction deprivation group demonstrated significantly less extinction recall than the normal sleep group did. There was no significant difference between the normal sleep and post-extinction deprivation group during extinction recall. Results indicated sleep deprivation before extinction training significantly disrupts extinction recall. CONCLUSIONS: These findings suggest that 1) sleep deprivation in the immediate aftermath of trauma could be a potential contributor to posttraumatic stress disorder development and maintenance via interference with natural extinction processes and 2) management of sleep symptoms should be considered during extinction-based therapy.