New research highlights the role of rumination as a mediator between insomnia and depression symptoms in adolescents. The findings suggest that reducing rumination alongside addressing sleep difficulties may improve therapeutic approaches for depression. The study was published in the Journal of Sleep Research.
Rumination is a repetitive style of thinking that is characterized by persistent negative thoughts and self-reflection, often exacerbating and prolonging negative emotional states. Researchers were motivated to study rumination due to its relevance to both insomnia and depression.
Sleep disturbance is a significant risk factor for the onset and relapse of depression, and targeting sleep has been explored as a means of indirectly reducing depression and other mental illnesses. Cognitive Behavioral Therapy for Insomnia (CBT-I), a treatment targeting sleep, has been shown to improve both sleep and depression outcomes. However, the mechanisms linking sleep disturbance and depression, as well as the mechanisms underlying the improvement in depression following CBT-I, are not well understood.
One factor common to both insomnia and depression is rumination. It has been described as an important mechanism underlying insomnia, along with unhelpful beliefs about sleep, according to Harvey’s cognitive model of insomnia. Empirical data supports the association between rumination and sleep disturbance in individuals with insomnia.
However, it is unclear whether CBT-I effectively targets rumination in adults. Additionally, rumination has been proposed as a mediator between insomnia and depression, suggesting its role in perpetuating the cycle of increased rumination and sleep difficulties, ultimately leading to depressive symptoms.
“Sleep problems are a powerful risk factor for depression onset,” said study author Sophie H. Li, a clinical psychologist and postdoctoral research fellow at the Black Dog Institute at the University of New South Wales.
“We also know that treating sleep problems, like insomnia, also improves depression. I was interested in understanding the mechanism underlying the association between insomnia and depression, because if we know this we can advance sleep treatments so they more effectively target both insomnia and depression.”
To investigate the role of rumination in the relationship between insomnia and depression, the researchers conducted a secondary analysis of data collected from a two-arm randomized controlled trial of Sleep Ninja®, a CBT-I smartphone app for adolescent insomnia. The study included 264 adolescents between the ages of 12 and 16 who reported elevated insomnia symptoms.
Participants were recruited through online channels and community pathways and were randomly assigned to either the intervention group (using the Sleep Ninja app) or the control group (receiving weekly SMS sleep tips). The intervention group received the Sleep Ninja app, which consisted of six training sessions derived from CBT-I principles. The sessions covered various aspects of sleep hygiene, cognitive therapy, and relapse prevention. The control group received weekly sleep tips via SMS, which were educational but non-therapeutic.
Several measures were used to assess insomnia symptoms, depression symptoms, rumination, and unhelpful beliefs about sleep.
The researchers found a strong connection between difficulties with sleep, feeling depressed, and rumination. Participants who had trouble sleeping were more likely to experience symptoms of depression, and those who ruminated more often were also more likely to feel depressed. Additionally, age and gender play a role, with females reporting more sleep problems, depression symptoms, rumination, and unhelpful beliefs about sleep.
When examining the effects of CBT-I, it was found that reductions in depression symptoms following the therapy could be attributed, at least in part, to reductions in rumination. CBT-I did not directly reduce rumination but did lead to a reduction in unhelpful beliefs about sleep.
“Sleep problems are an important, and treatable, risk factor for depression in adolescents,” Li told PsyPost. “Since seeking help for sleep problems is less stigmatizing compared to seeking help for depression, improving sleep is a promising means of indirectly preventing or alleviating depression in young people. Ensuring sleep treatments target rumination (or repetitive negative thinking more generally) may improve their effectiveness in reducing both insomnia and depression.”
The study had some limitations, such as the lack of distinction between pre-sleep rumination and rumination at other times of the day. Future research could incorporate momentary measures of rumination to explore their differential roles as mediators. Additionally, other potential mediators, such as pre-sleep arousal, should be considered in further investigations, the researchers said.
“Rumination only partially explained the link between insomnia and depression,” Li said. “More research is needed to understand the other mechanisms involved, which may include worry and pre-sleep hyperarousal.”
The study, “The role of rumination in the relationship between symptoms of insomnia and depression in adolescents“, was authored by Sophie H. Li, Brittany Corkish, Cele Richardson, Helen Christensen, and Aliza Werner-Seidler.