Three-Year Follow-Up of Insomnia and Hypnotics after Controlled Internet Treatment for Insomnia

To investigate the long-term effects of therapist-guided Internet-based insomnia treatment on insomnia severity and sleep medication use, compared with active control.

This study was an 8 week randomized controlled trial with follow-up posttreatment and at 6, 12, and 36 months, set at the Internet Psychiatry Clinic, Stockholm, Sweden. Participants were 148 media-recruited nondepressed adults with insomnia. Interventions were Guided Internet-based cognitive behavioral therapy for insomnia (ICBT-i) or active control treatment (ICBT-ctrl). Primary outcome was insomnia severity, measured with the Insomnia Severity Index. Secondary outcomes were sleep medication use and use of other treatments.

The large pretreatment to posttreatment improvements in insomnia severity of the ICBT-i group were maintained during follow-up. ICBT-ctrl exhibited significantly less improvement posttreatment (between-Cohen d = 0.85), but after 12 and 36 months, there was no longer a significant difference. The within-group effect sizes from pretreatment to the 36-months follow-up were 1.6 (ICBT-i) and 1.7 (ICBT-ctrl), and 74% of the interviewed participants no longer had insomnia diagnosis after 36 mo. ICBT-ctrl used significantly more sleep medication (P = 0.017) and underwent significantly more other insomnia treatments (P < 0.001) during the follow-up period.

The large improvements in the ICBT-i group were maintained after 36 months, corroborating that CBT for insomnia has long-term effects. After 36 months, the groups did not differ in insomnia severity, but ICBT-ctrl had used more sleep medication and undergone more other additional insomnia treatments during the follow-up period.

The trial was registered, together with a parallel trial, at Clinicaltrials.gov as "Internet-CBT for Insomnia" registration ID: NCT01256099.