Adult attachment, loneliness, and self-reported sleep outcomes: A secondary analysis of the Touch Test Study

Attachment dimensions and loneliness have independently been associated with sleep outcomes, with lower attachment insecurity and lower loneliness generally related to better sleep. However, it remains unclear whether attachment dimensions and loneliness interact in relation to sleep. The current study aimed to examine whether attachment anxiety and attachment avoidance moderated associations between loneliness and self-reported sleep outcomes.

A secondary data analysis was conducted using data from the Touch Test Study, which was originally run to measure outcomes and attitudes towards touch. Attachment dimensions, loneliness, and the interactions between loneliness and each attachment dimension were treated as independent variables. Sleep duration, sleep quality, time to fall asleep, and wake after sleep onset were treated as dependent variables. Adult participants from the UK (N = 15,049) with no health conditions or impairments were included in the study, having been originally recruited through opportunity sampling. The final analytic sample for the main models ranged from N = 11,901 to N = 11,916 across sleep outcomes.

Ordinal logistic regression showed that individuals with higher loneliness reported shorter sleep duration at higher levels of avoidant attachment. This was the only significant attachment × loneliness interaction in the adjusted models and remained significant after correction for multiple testing and in a sensitivity analysis excluding participants who reported sleeping more than nine hours.

These findings provide limited evidence that loneliness and avoidant attachment interact in relation to self-reported sleep duration. However, attachment × loneliness interactions were not observed for sleep quality, sleep onset, or wake after sleep onset. The findings suggest that attachment and loneliness may be relevant relational factors in sleep research, while recognising that the moderation effect observed here was specific to sleep duration and small in magnitude.