Does treating insomnia with digital cognitive behavioural therapy (Sleepio) mediate improvements in anxiety for those with insomnia and comorbid anxiety? An analysis using individual participant data from two large randomised controlled trials.
Henry AL., Miller CB., Emsley R., Sheaves B., Freeman D., Luik AI., Espie CA.
BACKGROUND: Considerable comorbidity exists between insomnia and anxiety, and evidence shows that the benefits of CBT for insomnia extend to anxiety. Using data from two large trials of digital CBT (dCBT) for insomnia, we evaluated whether improving sleep is an effective treatment target to reduce both insomnia and anxiety symptoms in individuals with insomnia and clinically significant anxiety. METHODS: This was a controlled sub-analysis combining individual participant data from two previous randomised controlled trials of dCBT for insomnia (Sleepio). Participants (N = 2172) with insomnia disorder and clinically significant anxiety symptoms were included in this sub-analysis and received either dCBT or control (usual care or sleep hygiene education). Assessments were evaluated at baseline, post-intervention (week 8 or 10), and follow-up (week 22 or 24). Mediation was evaluated using structural equation models. RESULTS: dCBT for insomnia was superior to control at reducing both insomnia (Hedges' g range = 0.77-0.81; both p