Investigating the Effectiveness of CBT-i Coach, a Free, Publicly Available mHealth App for Insomnia

CBT-i Coach is a free, publicly available mobile health application (app) that provides users with the core intervention components of cognitive behavioral therapy for insomnia (CBT-i). By making these components directly accessible to users, CBT-i Coach potentially circumvents barriers to accessing CBT-i, such as a scarcity of and lack of referral to trained providers. It may also serve a preventative function by helping address sleep disruption before it reaches clinical levels. However, no study to date has investigated the potential effectiveness of CBT-i Coach for either of these two purposes in public, naturalistic use. This study observed public CBT-i Coach use over an 18-month period to investigate whether users reporting either clinical or subclinical insomnia symptoms (N = 1618) showed improvement in insomnia symptoms, sleep efficiency, and sleep quality while using the app and whether clinically meaningful engagement with the app was associated with improvements. Users' insomnia symptoms, sleep efficiency, and sleep quality improved while using CBT-i Coach (d = 0.57, 0.41, and 0.24, respectively). Regarding clinically meaningful engagement, greater engagement with the My Sleep (b = -0.004) and Tools (b = -0.050) sections were associated with lower final insomnia symptoms, and greater engagement with the My Sleep section (b = 0.012) was associated with higher final sleep quality. CBT-i Coach therefore appears to be a valuable public health tool to improve sleep. It may also provide a preventative service by addressing sleep disruption among those with subclinical symptom levels who otherwise might not have access to CBT-i.