A randomized controlled trial comparing guided internet-based multi-component treatment and internet-based guided sleep restriction treatment to care as usual in insomnia

•Internet-based cognitive behavioral treatment (iCBT-I) is effective in insomnia.•An abridged iCBT-I focusing on sleep restriction is effective in insomnia.•The treatment gains remained stable up to six-month follow-up.•The effects of the two versions of iCBT-I did not differ from each other.•Patients were more satisfied with the full version of iCBT-I.