Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion in the review. The duration of follow-up in the included studies ranged from 1 month to 2 years.
Specific interventions included in the review
Studies investigating the effects of multifaceted CBT, including sleep scheduling, progressive muscle relaxation, sleep hygiene education and/or cognitive reconstructions, were eligible for inclusion; non-pharmacological treatments directly targeting circadian rhythms, white noise, acupuncture and exercise were excluded. Most of the included studies incorporated stimulus control and sleep hygiene; others employed cognitive reconstruction, a relaxation training, or an abbreviated format of CBT. Some studies also provided the participants with further material. Most treatments were delivered on an individual basis, in sessions lasting between 30 and 60 minutes weekly for between 6 and 10 weeks. All but one intervention (that was nurse-directed) were provided by a psychiatrist. The control interventions in the included studies were placebo, waiting list, single-component treatment group or pharmacological treatment.
Participants included in the review
Studies on adults between 18 and 65 years with primary insomnia (psycho-physiological insomnia according to DSM-IV, ICSD-R or ICD-10) were eligible; patients with other sleep disorders, such as circadian rhythm sleep disorder, periodic limb movements in sleep, severe medical or psychiatric conditions and substance use disorders, were excluded. The diagnosis of the participants in the included studies was established through structured interviews, self-report measures of insomnia, polysomnography, published checklists and laboratory tests. The mean age of the participants ranged from 36 to 65 years and more than half were female. The mean duration of symptoms, where reported, was more than 10 years.
Outcomes assessed in the review
The studies had to report sleep onset latency, number or duration of awakenings after sleep onset, sleep efficiency, sleep quality, beliefs and attitudes about sleep, or medication reduction to be eligible. The included studies primarily assessed sleep onset latency, wake time after sleep onset, sleep efficiency, total sleep time, total wake time and general sleep quality. All of the included studies measured sleep outcomes using daily sleep diaries; some studies also used established questionnaires.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.