Background: Insomnia is a symptom-defined disorder with a high societal burden related to missed work and lowered productivity. Depression is frequently associated with insomnia. Treatment is, primarily, medications prescribed to lengthen sleep time without attention to an underlying cause or to improve sleep quality. CBT administered by clinical psychologists is superior to medications but access to therapy is restricted due to a shortage of trained psychologists. We studied the effectiveness of internet-based CBT compared to standard care (sleep hygiene instruction). Methods: Patients referred to sleep clinics for insomnia were evaluated by survey instruments and actigraphy to determine the degree of insomnia and its effects: Beck Depression Inventory (BDI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), one week of actigraphy monitoring. Participants were then randomized to a modular internet-based CBT program (Sleep Coach) over a 6 week period or to receive standard sleep hygiene instruction (standard care). Internet-based CBT components include sleep hygiene, sleep restriction, stimulus control, behavior modification and relapse prevention. Assessments were repeated after intervention. Results: Sixteen patients (7 internet-based CBT, 9 standard care) completed the study. Mean pre/post improvements were seen in BDI (12.37.6, p=.09 ns), ISI (17.49.4, p<.01) and ESS (7.1
4.6, p=.03) for internet-based CBT. A significant improvement was found after sleep hygiene instruction in ISI (p=.01) but not BDI or ESS. The sleep length indices measured by actigraphy (Total Sleep Time, Wake After Sleep Onset, number of awakenings and sleep efficiency) were statistically unchanged after internet-based CBT or sleep hygiene instruction. Between-patient variability in survey/sleep indices was notable. Conclusions: Improvements in survey measures of insomnia were observed after internet -based CBT and sleep hygiene instruction, however, sleep length or efficiency measures were not improved by either intervention. Self-administered internet-based CBT is a promising treatment option for insomnia that includes attention to a potential cause. Considerable sleep pattern variability likely reflects the etiologically diverse population of insomnia patients enrolled in our study.