Neural processing of emotional stimuli before and after cognitive behavioural therapy for insomnia

BACKGROUND: Previous research has suggested an association between insomnia disorder (ID) and alterations in emotion processing. Therefore, it is crucial to investigate neurobiological changes in emotion processing in patients with ID before and after Cognitive Behavioral Therapy for Insomnia (CBT-I) and to compare them with healthy controls (HC) with task-based functional magnetic resonance imaging (fMRI). METHODS: 20 patients with ID and 20 HC were included in this study to view five different blocks of pictures with varying emotional arousal, valence, and content (sleep-relatedness) in the fMRI scanner. RESULTS: A significant Group × Session interaction was identified in the amygdala for both the sleep-related negative contrast (F(1,38) = 4.19, p = .048) and the neutral moderate contrast (F(1,38) = 5.39, p = .026). Post-hoc tests revealed that patients with ID had a significantly higher average amygdala reactivity to sleep-related stimuli at T0, whereas no significant difference was observed between the groups at T1. However, the analysis of Intraclass Correlation Coefficients (ICC) in the control group suggests a very low retest reliability across all fMRI measures. CONCLUSIONS: CBT-I may normalise amygdala responses to sleep-related negative stimuli, which may reflect a shift toward improved emotional processing. However, the very low retest reliability of fMRI measures warrants cautious interpretation of these results.