Automatic affective responses towards the bed in patients with primary insomnia: evidence for a negativity bias

Ruminating about sleep problems and negatively valenced thinking play a key role in the maintenance of sleep complaints in patients with insomnia. Based on associative learning principles, we hypothesized that repeated co-occurrence of negative thoughts (unconditioned stimulus) and the bedroom environment (conditioned stimulus) results in automatic negative affective responses towards the bed (conditioned response). Twenty-two insomniacs and 22 good sleepers performed a Single-Target Implicit Association Test measuring the strength of automatically triggered affective responses towards the bed. Results revealed a significant group difference, indicating a stronger negative affective response towards the bed in patients with insomnia. No correlations were found between the strength of negative affective responses towards the bed and subjective measures of sleep quality. As it might increase the stress experience further during bedtime, automatic negative responses towards the bed are likely to represent an additional factor accounting for the development and maintenance of sleep disorders and represent a potential target for therapeutic interventions.