This is the first longitudinal study of insomnia symptoms in a pediatric pain population. Our findings demonstrated that insomnia persisted over a one year period for youth with and without chronic pain. Adolescents with chronic pain endorsed more problems with insomnia than healthy adolescents. Specifically, about half of the adolescents with chronic pain reported significant problems with falling asleep or staying asleep that continued over the 12 month period in contrast to about 20% of the healthy cohort. This high rate of insomnia symptoms is similar to that reported in cross-sectional studies of youth with chronic pain 11, 22
, highlighting the importance of understanding the potential health impact of insomnia on youth with chronic pain given the frequency of this problem. It is important to note that insomnia symptoms also persisted among healthy youth in our sample who experienced everyday aches and pains, which is consistent with known associations between advancing pubertal development and increased risk for sleep problems during adolescence 6
In our analysis of the potential adverse health outcomes of insomnia, significant associations were found between persistent insomnia symptoms and poorer health-related quality of life over 12 months. This extends findings of studies that have shown that sleep difficulties (and particularly insomnia symptoms) at a single time point are associated with concurrent physical function limitations, poor quality of life, and greater depressive symptoms 11, 19, 22
. In addition, the analysis of outpatient medical service use showed that membership in the chronic pain cohort and persistent insomnia symptoms were related to a higher rate of utilization of outpatient medical services. Our study is the first to examine health service use in youth with chronic pain and comorbid insomnia. This finding extends similar work done in adults with chronic pain and insomnia that has also found a relationship to higher health service use including high costs of prescription medications 27, 29
. Together, our findings suggest that insomnia symptoms not only persist over time but contribute to a pattern of poor adolescent quality of life. Uninterrupted, this pattern may continue to impact quality of life and function into adulthood.
Using a model that we previously tested with cross-sectional survey data, we examined behavioral factors that may contribute to longitudinal insomnia symptoms. We found that insomnia symptoms over time were best predicted by behavioral factors (e.g., pre-sleep arousal, sleep hygiene) rather than by pain intensity, which is consistent with the conceptualization of perpetuating factors for the maintenance of insomnia. Although pain intensity may serve to precipitate difficulties with falling or staying asleep, over time, behaviors surrounding sleep habits and behaviors present at bedtime are likely to sustain problems with insomnia symptoms. For example, a high level of cognitive or somatic arousal at bedtime (e.g., worries about sleep, physiological hyperarousal) may directly interfere with falling asleep quickly and lead to negative sleep habits (e.g., taking long naps during the day) that sustain problems with insomnia.
There are several limitations of the study that should be kept in mind when interpreting findings. There is not currently consensus on the ideal measure to assess insomnia symptoms in children or adolescents. This is dissimilar to assessment of insomnia symptoms in adults where one measure, the Insomnia Severity Index 1, is the gold standard. Thus, the ability to make comparisons across pediatric studies is more limited due to the differing methods that have been reported. Nonetheless, similar rates of sleep problems and insomnia symptoms have been found across pediatric studies. We are the first group to report on the association of insomnia symptoms with health care utilization of children and adolescents with chronic pain. This analysis should be considered somewhat preliminary given that we collected parent report data on service use only rather than cost data specifically. Further research is needed to replicate these findings using objective measures of healthcare utilization such as medical chart review and billing records.
There are several factors that could influence differences in longitudinal trajectories of insomnia symptoms between youth with chronic pain and healthy youth which are beyond the scope of this manuscript. For example, prescription pain medication use may impact daytime and nighttime sleep patterns and contribute to the persistence of insomnia symptoms over time. Research is needed to examine longitudinal associations between prescription pain medication use and insomnia symptoms. The impact of school schedules on sleep patterns in youth with chronic pain is also unknown, and future research could examine differences in insomnia symptoms by the setting where the adolescent receives schooling (e.g., home school vs. public or private school). Differences in longitudinal trajectories of insomnia symptoms between youth with chronic pain and youth with other types of chronic illness are also unknown.
Given the high rate of insomnia symptoms experienced by adolescents with chronic pain and their relationship to physical and psychosocial quality of life, there is a clear need to develop and test sleep interventions in this population. Focused strategies aimed directly at targeting dysfunctional thoughts and behavioral patterns around sleep, such as stimulus control strategies and sleep restriction that are components of cognitive-behavioral therapy for insomnia, may lead to improvements in sleep behaviors.
Cognitive-behavioral therapy (CBT) has been recommended by the American Academy of Sleep Medicine (AASM) for the treatment of adult insomnia and has proven effective in diverse patient populations with comorbid medical conditions 23
. The primary treatment strategies of CBT for insomnia (CBT-I) include cognitive strategies to reduce dysfunctional thoughts about sleep, relaxation strategies to facilitate sleep onset, and stimulus control and sleep restriction to strengthen the association between sleep and the stimulus conditions under which sleep typically occurs. CBT-I has already been used effectively in adults with chronic pain and insomnia. For example, Vitiello and colleagues 33
demonstrated that not only do insomnia symptoms improve but that pain is also reduced in older adults receiving CBT-I.
CBT-I may also have substantial benefits for adolescents with chronic pain but this has not yet been evaluated. In fact, there is an extremely limited literature on treatment of sleep problems in children or adolescents with chronic pain. Only a few studies have evaluated any type of sleep intervention in pediatric pain populations. In one study of children with migraine 4
, children randomized to receive sleep hygiene education had reduced migraines compared to children in a standard care control group. In a study of youth with fibromyalgia 9
, sleep interventions were a component of a cognitive-behavioral intervention that was evaluated in an uncontrolled trial. Although both of these studies concluded that sleep intervention had positive effects on children’s pain, both trials were small, had limited assessment of sleep either at screening/enrollment or assessment of changes in sleep patterns or quality with treatment. Therefore, the efficacy of sleep interventions in pediatric pain populations is currently unknown. Well-designed trials of specific sleep interventions (e.g., CBT-I) are needed in children and adolescents with chronic pain.
Because of the adverse effects of inadequate sleep and sleep problems on children’s health, mood, and quality of life, assessment and treatment of sleep disturbances and disorders are an important part of the clinical care of children and adolescents with chronic pain.