Dieter Riemann

Insomnia as a predictor of depression: A meta-analytic evaluation of longitudinal epidemiological studies

BACKGROUND In many patients with depression, symptoms of insomnia herald the onset of the disorder and may persist into remission or recovery, even after adequate treatment. Several studies have raised the question whether insomniac symptoms may constitute an independent clinical predictor of depression. This meta-analysis is aimed at evaluating quantitatively if insomnia constitutes a predictor of depression. METHODS PubMed, Medline, PsycInfo, and PsycArticles databases were searched from 1980 until 2010 to identify longitudinal epidemiological studies simultaneously investigating insomniac complaints and depressed psychopathology. Effects were summarized using the logarithms of the odds ratios for insomnia at baseline to predict depression at follow-up. Studies were pooled with both fixed- and random-effects meta-analytic models in order to evaluate the concordance. Heterogeneity test and sensitivity analysis were computed. RESULTS Twenty-one studies met inclusion criteria. Considering all studies together, heterogeneity was found. The random-effects model showed an overall odds ratio for insomnia to predict depression of 2.60 (confidence interval [CI]: 1.98-3.42). When the analysis was adjusted for outliers, the studies were not longer heterogeneous. The fixed-effects model showed an overall odds ratio of 2.10 (CI: 1.86-2.38). LIMITATIONS The main limit is that included studies did not always consider the role of other intervening variables. CONCLUSIONS Non-depressed people with insomnia have a twofold risk to develop depression, compared to people with no sleep difficulties. Thus, early treatment programs for insomnia might reduce the risk for developing depression in the general population and be considered a helpful general preventive strategy in the area of mental health care.

Test–retest reliability and validity of the Pittsburgh Sleep Quality Index in primary insomnia

OBJECTIVE Psychometric evaluation of the Pittsburgh Sleep Quality Index (PSQI) for primary insomnia. METHODS The study sample consisted of 80 patients with primary insomnia (DSM-IV). The length of the test-retest interval was either 2 days or several weeks. Validity analyses were calculated for PSQI data and data from sleep diaries, as well as polysomnography. To evaluate the specificity of the PSQI, insomnia patients were compared with a control group of 45 healthy subjects. RESULTS In primary insomnia patients, the overall PSQI global score correlation coefficient for test-retest reliability was .87. Validity analyses showed high correlations between PSQI and sleep log data and lower correlations with polysomnography data. A PSQI global score > 5 resulted in a sensitivity of 98.7 and specificity of 84.4 as a marker for sleep disturbances in insomnia patients versus controls. CONCLUSION The PSQI has a high test-retest reliability and a good validity for patients with primary insomnia.

Sleep and depression--results from psychobiological studies: an overview.

Disturbances of sleep are typical for most depressed patients and belong to the core symptoms of the disorder. Polysomnographic sleep research has demonstrated that besides disturbances of sleep continuity, in depression sleep is characterized by a reduction of slow wave sleep and a disinhibition of REM sleep, with a shortening of REM latency, a prolongation of the first REM period and increased REM density. These findings have stimulated many sleep studies in depressive patients and patients with other psychiatric disorders. In the meantime, several theoretical models, originating from basic research, have been developed to explain sleep abnormalities of depression, like the two-process-model of sleep and sleep regulation, the GRF/CRF imbalance model and the reciprocal interaction model of non-REM and REM sleep regulation. Interestingly, most of the effective antidepressant agents suppress REM sleep. Furthermore, manipulations of the sleep-wake cycle, like sleep deprivation or a phase advance of the sleep period, alleviate depressive symptoms. These data indicate a strong bi-directional relationship between sleep, sleep alterations and depression.

Primary insomnia: a risk factor to develop depression?

BACKGROUND Chronic insomnia afflicts approximately 5-10% of the adult population in Western industrialized countries. Insomnia may be secondary, i.e. triggered and/or maintained by psychiatric/organic illnesses, the intake of prescribed/illicit drugs or alcohol, or by a combination of these factors. Insomnia can also occur as primary insomnia, caused by a psychophysiological hyperarousal process. In the present review a literature search was undertaken to identify longitudinal epidemiological studies which investigate the question whether primary insomnia at baseline predicts the development of depression at follow-up measurements. METHODS MEDLINE search for the medical subject headings insomnia and depression; identification of longitudinal epidemiological studies with at least two measurement points 1 year apart measuring insomnia and depression and indicating explicit criteria for both disorders. RESULTS Eight relevant epidemiological studies were identified. Almost unambiguously insomnia at baseline significantly predicted an increased depression risk at follow-up 1-3 years later. CONCLUSION As insomniac symptoms alone seem to be of predictive value for the development of depression in the succeeding years, it would be worthwhile to investigate if early adequate treatment is able to prevent psychiatric sequelae of primary insomnia.

Interleukin-6-(IL-6) plasma levels in depression and schizophrenia: comparison between the acute state and after remission

The concentration of cytokines such as Interleukin-6 (IL-6) has been reported to be elevated in depressed and schizophrenic patients and, in healthy persons, upon stress. Interleukin-6 plasma levels were determined in depressed (n = 12) and schizophrenic (n = 32) patients during the acute state of illness and after remission at approximately 8 weeks after admission and were compared with healthy controls (n = 12). Patients were diagnosed according to DSM-III-R by the Structured Clinical Interview (SLID). Severity of illness was assessed for depression by the Montgomery Asberg Depression Rating Scale (MADRS) and for schizophrenia by the Brief Psychiatric Rating Scale (BPRS). Interleukin-6 plasma concentrations were elevated during the acute state either of depression or of schizophrenia if compared to controls. After remission, IL-6 concentrations in depressed and in schizophrenic patients had decreased and did not differ significantly from controls. We hypothesize that the elevated IL-6 levels during the acute state of depression or schizophrenia may reflect an unspecific stress response.

Sleep and emotions: A focus on insomnia

Insomnia disorder is defined as difficulties in initiating/maintaining sleep and/or non-restorative sleep accompanied by decreased daytime functioning, persisting for at least four weeks. For many patients suffering from depression and anxiety, insomnia is a pervasive problem. Many of the aetiological theories of insomnia postulate that heightened emotional reactivity contributes to the maintenance of symptoms. This review focuses on the role of emotional reactivity in insomnia, and how the relationship between insomnia and depression and anxiety may be mediated by emotional reactivity. Furthermore, studies investigating the valence of emotions in insomnia are reviewed. Overall, there is empirical evidence that dysfunctional emotional reactivity might mediate the interaction between cognitive and autonomic hyperarousal, thus contributing to the maintenance of insomnia. Moreover, dysfunctions in sleep-wake regulating neural circuitries seem to be able to reinforce emotional disturbances. It seems plausible that dysfunctional emotional reactivity modulates the relationship between insomnia and depression and anxiety. Considering the interaction between sleep and emotional valence, poor sleep quality seems to correlate with high negative and low positive emotions, both in clinical and subclinical samples. Good sleep seems to be associated with high positive emotions, but not necessarily with low negative emotions. This review underlines the need for future research on emotions in insomnia.

Prevalence and treatment of insomnia in general practice. A longitudinal study

SummaryThe aim of the study was to assess prevalence and treatment modalities of insomnia in general practice. To investigate the course of insomnia, a longitudinal study design was adopted. Two thousand five hundred and twelve patients (age 18–65 years) were investigated with a questionnaire in general practice (T1). Four months later (T2) and again 2 years later (T3) a questionnaire was sent to all patients who had complained about severe insomnia at the time of the first inquiry. To assess insomnia, operationalized diagnostic criteria were applied (DSM-III-R). Eighteen point seven percent suffered from severe, 12.2% suffered from moderate and 15% suffered from mild insomnia. In the course of 2 years insomnia appeared as a chronic health problem. A high comorbidity of severe insomnia was found with chronic somatic and psychiatric disorders, especially with depression. Of the severely insomniac patients, 23.9% used prescribed hypnotics habitually, mainly benzodiazepines. The use of prescribed hypnotics remained rather stable during the whole study period. More than half of the patients reported a daily use of the hypnotics for 1–5 years or longer, but only 22% of the severely insomniac patients reported at the time of the third inquiry a significant improvement of insomnia due to the administration of sleeping pills. Thus, the long-term administration of benzodiazepine hypnotics seems to be an inadequate treatment strategy in chronic insomnia. Whether the occurrence of rebound insomnia after benzodiazepine withdrawal may be one of the main factors for chronic hypnotic use requires discussion. Although insomnia may be an important symptom of many somatic and psychiatric disorders, the general practitioner was unaware in more than half of the cases that the patients suffered from a sleep problem. Severe insomniac patients displayed a higher mean number of medical consultations compared with good sleepers or patients with mild insomnia, indicating that insomnia constitutes a significant burden for the primary care physicians.

The treatments of chronic insomnia: A review of benzodiazepine receptor agonists and psychological and behavioral therapies

The present review provides an assessment of the efficacy and safety of benzodiazepine receptor agonists (BZRAs) and psychological and behavioral interventions for insomnia. These methods include relaxation techniques, sleep hygiene rules, stimulus control, sleep restriction and cognitive techniques, often also referred to as cognitive-behavioral therapy (CBT) when encompassing cognitive strategies and at least one kind of behavioral intervention. In order to provide a comprehensive assessment of the literature regarding the efficacy and safety of these standard treatments for insomnia, an integrative synthesis of the existing meta-analytic studies for each of the various treatment modalities was conducted. Where meta-analytic studies were not available, data from double-blind placebo-controlled randomized controlled trials (RCTs) were included. The summary findings from this review are (1) BZRAs and psychological and behavioral methods are effective to treat insomnia in the short-term and the latter have significantly more durable effects when active treatment is discontinued; and (2) there is only very limited evidence that BZRAs retain their efficacy during long-term treatment. The present review underscores the need for further research regarding the comparative efficacy and safety of these treatments for insomnia, how this varies with age and comorbidity, and how the various treatment modalities impact (1) daytime functioning, (2) quality of life, (3) health care utilization; and (4) pharmacoeconomics. Finally, it is particularly important that studies be conducted to determine if successful insomnia treatment influences the clinical course of the diseases that often occur co-morbidly with sleep continuity disturbance.

Nocturnal cortisol and melatonin secretion in primary insomnia

The present study investigated evening and nocturnal serum cortisol and melatonin concentrations in patients with primary insomnia to test if this clinical condition is accompanied by an increase of cortisol secretion and a simultaneous decrease of nocturnal melatonin production. Ten drug-free patients (4 males, 6 females) with primary insomnia (mean age+/-S.D.: 39.2+/-9.1 years) and 10 age- and gender-matched healthy controls participated in the study. All subjects spent three consecutive nights in the sleep laboratory with polysomnography. Measurement of cortisol and melatonin (from 19:00 h to 09:00 h) was performed prior to and during the last laboratory night. Contrary to expectation, cortisol secretion did not differ between healthy controls and insomniac patients. On the other hand, nocturnal melatonin production was significantly diminished in insomniac patients. Polysomnographically determined sleep patterns, in contrast to subjective ratings of sleep, demonstrated only minor alterations of sleep in the insomniac group. The lack of increased cortisol secretion in the patients with primary insomnia indicates that results from studies on the biological consequences of experimental sleep loss in healthy subjects cannot be applied to primary insomnia in general, especially if there are only minor objective sleep alterations. In spite of the negligible objective sleep disturbances in the present sample, nocturnal melatonin production was reduced, which tentatively suggests a role for this hormone in primary insomniacs. The pathophysiological significance of this finding is, however, still a matter of debate.

Prevalence of insomnia in elderly general practice attenders and the current treatment modalities

This study aimed to assess the prevalence and treatment modalities of elderly practice attenders. A total of 330 patients aged over 65 years were investigated with a questionnaire in general practice. To assess insomnia, operationalized diagnostic criteria according to DSM‐III‐R were applied. Twenty‐three percent of the elderly patients suffered from severe, 17% from moderate and 17% from mild insomnia. More than 80% of the patients reported suffering from insomnia for 1–5 years or longer, which indicates a chronic course. Elderly patients showed unrealistic expectations concerning duration of sleep and spend more time in bed than they realistically can expect to sleep. More than half of the elderly patients reported habitual daytime napping. Sleep‐disturbed elderly patients did not differ significantly from good sleepers in their habit of taking daytime naps, but even when taking daytime naps, good sleepers slept significantly longer than the sleep‐disturbed patients. A significant association was found between insomnia and mental disorders, i.e., depression and organic brain syndrome according to the diagnosis of the general physician. In about half of the cases the primary care physician was not aware that the elderly patient suffered from severe insomnia. More than half of the elderly severe insomniacs took prescribed hypnotics habitually, mainly benzodiazepines.