Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary

Introduction: The quality of the first, close relationship – the attachment – has a great influence on the later social contacts. Since we know that sleep architecture is affected by the quality of wakefulness, it is expected that brain activity during sleep reflects attachment security. We hypothesised that persons with insecure attachment experience more anxiety and stress during normal social life than those with a secure one. Suggested function of REM sleep is to process daytime emotional stress, so we investigated REM sleep features in relation with attachment security.
Methods: Dream recall frequency, recurrent nightmare experience and attachment styles (RSQ) were examined by questionnaires in 90 healthy volunteers. Twelve of the subjects slept two nights in the sleep laboratory, undergoing polysomnography. EEG activity in the delta (0.5–4.5 Hz), theta (4.75–7.75 Hz), as well as slow (8–10 Hz)- and fast (10.25–12 Hz) alpha bands were calculated by FFT. Dream and sleep variables were correlated with factor scores of the RSQ designed to assess adult attachment.
Results: Lowest dream recall scores were reported by the securely attached group (P < 0.1). Insecure groups did not differ. Attachment anxiety was associated with higher frequency of recurrent nightmare experience. We found that REM sleep per cent positively correlates with the product of anxiety and avoidance scores of attachment. Also a positive correlation between the duration and percentage of S4 sleep and attachment anxiety emerged. Quantitative EEG analysis resulted in positive correlations between the power spectral density of fast alpha activity (O2) and attachment anxiety, as well as between the mean frequency of frontal 6.5–12 Hz EEG activity and attachment anxiety.
Discussion: Questionnaire-based as well as physiological results supported our hypothesis that attachment security is reflected in REM sleep features.