In this double-blind, randomized, placebo-controlled, parallel-group trial, 60 patients were randomly assigned to either the IHT/verum or control/placebo (1:1) groups. Patient-compliant sleep diaries (6 items; 1: time to fall asleep, 2: time to wake up midnight, 3: time to wake up too early, 4: time spent in bed, 5: total sleep time in hours, 6: sleep efficiency) and the Insomnia Severity Index (ISI) were used as primary and secondary outcomes, respectively, and measured at baseline and 3 months later.
