Very long-term outcome of cognitive behavioral therapy for insomnia: one- and ten-year follow-up of a randomized controlled trial.

Insomnia is a common and chronic disorder, and cognitive behavioral therapy (CBT) is the recommended treatment. Very long-term follow-ups of CBT are very rare, and this study aimed to investigate if improvements were stable one and ten years after CBT for insomnia (CBT-i). Based on a three-armed randomized controlled trial of bibliotherapeutic CBT-i, participants received an insomnia-specific self-help book and were randomized to therapist guidance, no guidance, or a waitlist receiving unguided treatment after a delay. Six weeks of treatment was given to 133 participants diagnosed with insomnia disorder. After one and ten years, participants were assessed with self-reports and interviews. Improvements were statistically significant and well maintained at one- and ten-year follow-ups. Average Insomnia Severity Index score [95%CI] was 18.3 [17.7-18.8] at baseline, 10.1 [9.3-10.9] at post-treatment, 9.2 [8.4-10.0] at one- and 10.7 [9.6-11.8] at ten-year follow-up, and 64% and 66% of participants no longer fulfilled criteria for an insomnia diagnosis at one and ten years, respectively. Positive effects of CBT were still present after ten years. Insomnia severity remained low, and two-thirds of participants no longer fulfilled criteria for an insomnia diagnosis. This extends previous findings of CBT, further confirming it as the treatment of choice for insomnia.

A very brief self-report scale for measuring insomnia severity using two items from the Insomnia Severity Index - development and validation in a clinical population.

OBJECTIVE: To develop a very brief scale with selected items from the Insomnia Severity Index (ISI), and to investigate the psychometric properties of the proposed scale in a psychiatric sample. METHODS: Patient data from seven Cognitive Behavioral Therapy (CBT) for insomnia trials and from regular care were used in psychometric analyses (N = 280-15 653). The samples included patients screening (N = 6936) or receiving treatment (N = 1725) for insomnia and other psychiatric conditions. Six criteria relating to component structure, sensitivity to change and clinical representativeness were used to select items. Psychometric analyses for the proposed very brief scale were performed. RESULTS: One item representing satisfaction/dissatisfaction with current sleep pattern and one item representing interferences with daily functioning, were selected to create the 2-item ISI version. Correlations with the full scale were high at screening, pre and post, and for change (0.82-0.94). Categorical omega was ⍵C = 0.86. With a cut-off of 6 points, the scale could detect Insomnia Disorder with a sensitivity of 84% and a specificity of 76%, which was close to the full ISI showing 86% and 80% respectively. CONCLUSIONS: The systematic psychometric evaluation based on a large sample from different contexts makes the proposed 2-item ISI version (ISI-2) a strong candidate for a very brief scale measuring insomnia, both for detecting cases and for measuring change during CBT with an overall high discriminative validity. ISI-2 is especially useful in clinical settings or population studies where there is a need to measure more than one condition at a time without overburdening patients. CLINICAL TRIALS: Trials used in this analysis: ClinicalTrials.gov identifier: NCT01105052 (https://www.clinicaltrials.gov/ct2/show/NCT01105052) (sample b), ClinicalTrials.gov identifier: NCT01256099 (https://clinicaltrials.gov/ct2/show/NCT01256099) (sample c and d), German clinical trial (DRKS), registration ID: DRKS00008745 (https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00008745) (sample e), ClinicalTrials.gov identifier: NCT01663844 (https://clinicaltrials.gov/ct2/show/NCT01663844) (sample f and g), ClinicalTrials.gov Identifier: NCT02743338 (https://clinicaltrials.gov/ct2/show/NCT02743338) (sample h).