A temporal path between sleep and pain, via mood, has been identified in adolescents with insomnia, suggesting that adolescence is a key time in which interventions to prevent chronic insomnia and pain are pivotal, according to research results published in Pain.
To date, only 1 longitudinal study — and no studies including nonclinical samples — have examined how mood mediates the sleep-pain relationship in adolescents, and only 1 model has addressed the relationship across the lifespan. To rectify this, researchers sought to examine the bidirectional, temporal relationship of insomnia symptoms and pain with depressed mood, anxious mood, and positive affect as mediators.
Longitudinal data from early, mid, and late adolescence were used to make this evaluation.
The patient sample included students in the Three Cities Study, a 5-year longitudinal project from 2014 to 2018 in 3 communities in Sweden. Five waves of data collection were made in total; a sample of 2776 students participated in the first wave, forming the baseline sample. A total of 1132 students (40.9% of the baseline sample) completed all 5 measurements.
Within the study, musculoskeletal pain was defined as pain in the back, neck, or shoulders. Researchers measured pain intensity, pain frequency, and pain interference. The Insomnia Severity Index was used to measure insomnia symptoms and clinical insomnia, as well as change over time.
Mood and affect were evaluated by the Center for Epidemiology Studies Depression Scale for Children (CES-DC) Depressed Mood subscale, the Overall Anxiety and Impairment Scale, and the CES-DC Positive Affect subscale.
At baseline, 11.7% of participants reported a pain frequency of once per week, comparable to a 12.5% prevalence reported in the general population of Swedish 13-year-olds. Girls scored significantly higher on all key variables compared with boys, except for positive affect, which had an inverted relationship. Age was not significantly associated with key variables.
In an unrestricted, configural, longitudinal measurement model, all latent variables correlated significantly with each other at all timepoints. The lowest correlations were noted between positive affect and pain, ranging from r=0.087 to r=0.300. The highest correlations were noted between depressed and anxious mood (range, r=0.833-0.418).
Three latent, longitudinal, full mediation models were fitted, each of which included a mediator at all 5 measurement points. Each model included direct bidirectional cross-lagged paths between insomnia and pain at every other timepoint: wave 1 to wave 3, wave 2 to wave 4, and wave 3 to wave 5.
Investigators noted a significant overall effect of insomnia symptoms from wave 1 on pain at wave 5 (0.244; 99% confidence interval [CI], 0.151-0.326), in addition to a significant overall effect of pain in wave 1 to insomnia at wave 5 (0.087; 99% CI, 0.048-0.128). A bidirectional relationship between insomnia and pain was also confirmed.
Depressed mood mediated the effect of insomnia symptoms in wave 1 to pain in wave 5; the overall indirect effect was 0.029 (95% CI, 0.011-0.054), representing 16.9% of the total effect. Depressed mood did not, however, mediate the overall total effect from pain in wave 1 to insomnia in wave 5 (0.004; 99% CI, 0.000-0.011).
Positive affect did not mediate the effects from insomnia to pain nor from pain to insomnia (0.005 and 0.000; 99% CI, 0.007 to -0.017 and -0.004 to 0.003). Anxious mood did mediate the overall indirect effect from insomnia to pain (wave 1 to wave 5; 0.031; 99% CI, 0.010-0.061; 15.5% of the overall total effect), and the overall indirect effect from pain to insomnia in wave 1 to wave 5 was nonsignificant (0.004; 99% CI, 0.000-0.012).
Study limitations include a priori data collection, inability to assess additional potential mediators like repetitive negative thinking, a reliance on self-report measures, the rate of missing data, and the potential for omitted variables affecting results.
“Adolescence…appears to be a pivotal developmental period for implementing interventions to prevent insomnia and pain from developing and becoming chronic,” the researcher wrote. “Hybrid interventions, combining elements from both Cognitive Behavioral Therapy (CBT) for insomnia and CBT for pain have shown promising results.”
“The current results indicate that it may be critical to specifically integrate depressed and anxious mood as clinical components in future hybrid interventions, to further improve treatment effects, especially regarding pain,” they concluded.
Arnison T, Schrooten MGS, Hesser H, Jansson-Fröjmark M, Persson J. Longitudinal, bidirectional relationships of insomnia symptoms and musculoskeletal pain across adolescence: the mediating role of mood. Pain. Published online May 12, 2021. doi:10.1097/j.pain.000000000002334