Editorial: Insomnia: A Heterogenic Disorder Often Comorbid With Other Disorders and Diseases

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).

Previous research has identified insomnia as a predictor for the onset of depression. The aim of this meta-analysis is to investigate whether insomnia also predicts the onset of other mental disorders. Longitudinal studies were eligible for inclusion if they investigated insomnia at baseline (including nighttime- and daytime-symptoms) as a predictor of the later onset of psychopathology within a follow-up time-frame of at least 12 mo. Thirteen primary studies were included. The results suggest that insomnia is a significant predictor for the onset of depression (10 studies, OR 2.83, CI 1.55-5.17), anxiety (six studies, OR 3.23, CI 1.52-6.85), alcohol abuse (two studies, OR 1.35, CI 1.08-1.67, and psychosis (one study, OR 1.28, CI 1.03-1.59). The overall risk of bias in the primary studies was moderate. This meta-analysis provides evidence that insomnia increases the risk for psychopathology. A future research agenda should include more prospective studies using established diagnostic criteria, assessing insomnia at baseline and including long-term follow-up intervals evaluating a wider range of mental disorders. In addition, prospective long-term interventional studies investigating the efficacy of insomnia treatment for the prevention of mental disorders are called for.

As part of the National Institute of Mental Health Epidemiologic Catchment Area study, 7954 respondents were questioned at baseline and 1 year later about sleep complaints and psychiatric symptoms using the Diagnostic Interview Schedule. Of this community sample, 10.2% and 3.2% noted insomnia and hypersomnia, respectively, at the first interview. Forty percent of those with insomnia and 46.5% of those with hypersomnia had a psychiatric disorder compared with 16.4% of those with no sleep complaints. The risk of developing new major depression was much higher in those who had insomnia at both interviews compared with those without insomnia (odds ratio, 39.8; 95% confidence interval, 19.8 to 80.0). The risk of developing new major depression was much less for those who had insomnia that had resolved by the second visit (odds ratio, 1.6; 95% confidence interval, 0.5 to 5.3). Further research is needed to determine if early recognition and treatment of sleep disturbances can prevent future psychiatric disorders.