Associations between insomnia, anxiety and repetitive negative thinking in youths

Abstract

Insomnia is the most prevalent sleep problem among youth. It has a significant impact on their physiological, cognitive and psychological well-being. Existing research established the relationship between insomnia and anxiety and the potential role of repetitive negative thinking (RNT) in this association. This thesis aims to explore the multifaceted effects of insomnia on youth, with a particular focus on its connection with anxiety and RNT. Previous research have primarily focused on examining pairs of relationships among insomnia, anxiety, and RNT, the interplay between these factors remained unclear. Hence, this thesis has two objectives: first, to investigate the relationships among insomnia, anxiety, and RNT and to examine whether RNT mediates the relationship between insomnia and anxiety severity in youth; second, to evaluate the effectiveness of Cognitive Behavioural Therapy for Insomnia (CBT-I) in reducing anxiety severity, improving insomnia symptoms and decreasing RNT level, compared to a waitlist control group. The first study was a cross-sectional study involving 399 youths (ages 12 to 24) who completed online questionnaires to assess their insomnia severity (as measured by Insomnia Severity Index), anxiety severity (as measured by The Depression Anxiety Stress Scale – Anxiety Subscale), and level of RNT (as measured by Perseverative Thinking Questionnaire). Results revealed significant correlations among insomnia, anxiety, and RNT (p <.001). RNT was also identified as a partial mediator between insomnia and anxiety symptoms, showing that RNT played a vital role in understanding the mechanism between insomnia and anxiety disorders. The second study was a randomised controlled trial with 57 adolescents (ages 12 to 20) diagnosed with insomnia disorder and anxiety symptoms. This study examined the effectiveness of group-based CBT-I on anxiety severity in youth. Participants in the CBT-I group showed significant improvement in anxiety and insomnia symptoms compared to the waitlist control group. Although changes in RNT as a mediator between treatment conditions and anxiety severity were insignificant, the study affirmed the efficacy of CBT-I in addressing co-occurring conditions of insomnia and anxiety in youth. Further studies should include longitudinal follow-up assessments and explore various psychological factors, such as locus of control and emotional regulation, to enhance the understanding of the interaction between insomnia and anxiety in youth populations.