Guided internet cognitive behavioral therapy for insomnia compared to a control treatment - A randomized trial.

Aim: To evaluate if internet-delivered Cognitive Behavioral Therapy for insomnia (ICBT-i) with brief therapist support outperforms an active control treatment.

Method: Adults diagnosed with insomnia were recruited via media (n = 148) and randomized to either eight weeks of ICBT-i or an active internet-based control treatment. Primary outcome was the insomnia severity index (ISI) assessed before and after treatment, with follow-ups after 6 and 12 months. Secondary outcomes were use of sleep medication, sleep parameters (sleep diary), perceived stress, and a screening of negative treatment effects. Hierarchical Linear Mixed Models were used for intent-to-treat analyses and handling of missing data.

Results: ICBT-i was significantly more effective than the control treatment in reducing ISI (Cohen's d = 0.85), sleep medication, sleep efficiency, sleep latency, and sleep quality at post-treatment. The positive effects were sustained. However, after 12 months the difference was no longer significant due to a continuous decrease in ISI among controls, possibly due to their significantly higher utilization of insomnia relevant care after treatment. Forty-six negative effects were reported but did not differ between interventions.

Conclusions: Supported ICBT-i is more effective than an active control treatment in reducing insomnia severity and treatment gains remain stable one year after treatment.