Background: Insomnia increases the likelihood of developing a mood or anxiety disorder. Moreover, symptoms of anxiety and depression, such as worry and rumination, contribute to insomnia. Given these relationships, there is a need to delineate how these disorders respond to treatment when they are comorbid.
Methods: 266 individuals presenting for anxiety and/or depression symptoms participated in this study in which symptoms of insomnia, anxiety, depression, disability, and sleep length were assessed. 102 of these patients were treated with internet-based cognitive behavioral therapy (iCBT) for anxiety and/or depression and 61 completed the treatment. Pre- to post-treatment symptom changes were examined in this subset.
Results: Insomnia, as measured by the Insomnia Severity Index, was evident in 40% of the patients. Individuals with insomnia reported more severe symptoms of anxiety and depression than individuals without insomnia. iCBT focused on anxiety and/or depression was associated with reductions in symptoms of insomnia, anxiety, depression, and disability. Total sleep time did not change over treatment.
Limitations: As the data were collected in routine care, there was no control group and no longer term follow-up assessment.
Conclusions: These findings highlight the importance of insomnia across anxiety and depressive disorders. They further demonstrate that treatment for anxiety and/or depression appears to improve comorbid insomnia symptoms, though may be ineffective in changing sleep duration.
Keywords: Anxiety; CBT; Comorbidity; Depression; Insomnia; Sleep.
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