Insomnia disorder: State of the science and challenges for the future

Background: Insomnia is a prevalent health complaint that is often difficult to evaluate reliably. There is an important need for brief and valid assessment tools to assist practitioners in the clinical evaluation of insomnia complaints.Objective: This paper reports on the clinical validation of the Insomnia Severity Index (ISI) as a brief screening measure of insomnia and as an outcome measure in treatment research. The psychometric properties (internal consistency, concurrent validity, factor structure) of the ISI were evaluated in two samples of insomnia patients.Methods: The first study examined the internal consistency and concurrent validity of the ISI in 145 patients evaluated for insomnia at a sleep disorders clinic. Data from the ISI were compared to those of a sleep diary measure. In the second study, the concurrent validity of the ISI was evaluated in a sample of 78 older patients who participated in a randomized-controlled trial of behavioral and pharmacological therapies for insomnia. Change scores on the ISI over time were compared with those obtained from sleep diaries and polysomnography. Comparisons were also made between ISI scores obtained from patients, significant others, and clinicians.Results: The results of Study 1 showed that the ISI has adequate internal consistency and is a reliable self-report measure to evaluate perceived sleep difficulties. The results from Study 2 also indicated that the ISI is a valid and sensitive measure to detect changes in perceived sleep difficulties with treatment. In addition, there is a close convergence between scores obtained from the ISI patient's version and those from the clinician's and significant other's versions.Conclusions: The present findings indicate that the ISI is a reliable and valid instrument to quantify perceived insomnia severity. The ISI is likely to be a clinically useful tool as a screening device or as an outcome measure in insomnia treatment research.

This European guideline for the diagnosis and treatment of insomnia was developed by a task force of the European Sleep Research Society, with the aim of providing clinical recommendations for the management of adult patients with insomnia. The guideline is based on a systematic review of relevant meta-analyses published till June 2016. The target audience for this guideline includes all clinicians involved in the management of insomnia, and the target patient population includes adults with chronic insomnia disorder. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) system was used to grade the evidence and guide recommendations. The diagnostic procedure for insomnia, and its co-morbidities, should include a clinical interview consisting of a sleep history (sleep habits, sleep environment, work schedules, circadian factors), the use of sleep questionnaires and sleep diaries, questions about somatic and mental health, a physical examination and additional measures if indicated (i.e. blood tests, electrocardiogram, electroencephalogram; strong recommendation, moderate- to high-quality evidence). Polysomnography can be used to evaluate other sleep disorders if suspected (i.e. periodic limb movement disorder, sleep-related breathing disorders), in treatment-resistant insomnia, for professional at-risk populations and when substantial sleep state misperception is suspected (strong recommendation, high-quality evidence). Cognitive behavioural therapy for insomnia is recommended as the first-line treatment for chronic insomnia in adults of any age (strong recommendation, high-quality evidence). A pharmacological intervention can be offered if cognitive behavioural therapy for insomnia is not sufficiently effective or not available. Benzodiazepines, benzodiazepine receptor agonists and some antidepressants are effective in the short-term treatment of insomnia (≤4 weeks; weak recommendation, moderate-quality evidence). Antihistamines, antipsychotics, melatonin and phytotherapeutics are not recommended for insomnia treatment (strong to weak recommendations, low- to very-low-quality evidence). Light therapy and exercise need to be further evaluated to judge their usefulness in the treatment of insomnia (weak recommendation, low-quality evidence). Complementary and alternative treatments (e.g. homeopathy, acupuncture) are not recommended for insomnia treatment (weak recommendation, very-low-quality evidence).