Schizophrenia and depression: The relation between sleep quality and working memory

Molecular characterization of the circadian clock in patients with Parkinson's disease-CLOCK4PD Study protocol

INTRODUCTION

Circadian rhythms (CRs) orchestrate intrinsic 24-hour oscillations which synchronize an organism's physiology and behaviour with respect to daily cycles. CR disruptions have been linked to Parkinson's Disease (PD), the second most prevalent neurodegenerative disorder globally, and are associated to several PD-symptoms such as sleep disturbances. Studying molecular changes of CR offers a potential avenue for unravelling novel insights into the PD progression, symptoms, and can be further used for optimization of treatment strategies. Yet, a comprehensive characterization of the alterations at the molecular expression level for core-clock and clock-controlled genes in PD is still missing.

METHODS AND ANALYSIS

The proposed study protocol will be used to characterize expression profiles of circadian genes obtained from saliva samples in PD patients and controls. For this purpose, 20 healthy controls and 70 PD patients will be recruited. Data from clinical assessment, questionnaires, actigraphy tracking and polysomnography will be collected and clinical evaluations will be repeated as a follow-up in one-year time. We plan to carry out sub-group analyses considering several clinical factors (e.g., biological sex, treatment dosages, or fluctuation of symptoms), and to correlate reflected changes in CR of measured genes with distinct PD phenotypes (diffuse malignant and mild/motor-predominant). Additionally, using NanoStringⓇ multiplex technology on a subset of samples, we aim to further explore potential CR alterations in hundreds of genes involved in neuropathology pathways.

DISCUSSION

CLOCK4PD is a mono-centric, non-interventional observational study aiming at the molecular characterization of CR alterations in PD. We further plan to determine physiological modifications in sleep and activity patterns, and clinical factors correlating with the observed CR changes. Our study may provide valuable insights into the intricate interplay between CR and PD with a potential to be used as a predictor of circadian alterations reflecting distinct disease phenotypes, symptoms, and progression outcomes.

Poor sleep quality in schizophrenia patients: A systematic review and meta-analyses of epidemiological and case-control studies

OBJECTIVE

Poor sleep quality is common in patients with schizophrenia but estimated prevalence rates in this population have been mixed. This systematic review and meta-analysis examined the prevalence of poor sleep quality in schizophrenia samples and moderators of prevalence from epidemiological studies as well as the risk of poor sleep quality in schizophrenia patients based on case-control studies.

METHODS

Both international (PubMed, Web of Science, PsycINFO, EMBASE) and Chinese databases [Chinese Nation knowledge Infrastructure (CNKI) and WANFANG] were systematically searched. Studies that estimated the prevalence of poor sleep quality in schizophrenia were analyzed using a random effects model. Funnel plots and Egger's tests were used to assess publication bias. Statistical analyses were performed using R software.

RESULTS

In total, 23 epidemiological studies and nine case-control studies were included. Based on the epidemiological studies, the pooled overall prevalence of poor sleep quality was 63.4 % [95 % confidence interval (CI): 57.0 %-69.9 %]. Additionally, based on the nine case-control studies, schizophrenia patients had a significantly higher risk for poor sleep quality compared to healthy controls [odd ratio (OR) = 4.5; 95%CI: 2.4-8.3; P < 0.0001].

CONCLUSION

Poor sleep quality is common among schizophrenia patients. Considering negative outcomes caused by poor sleep quality, regular screening on poor sleep quality should be conducted and effective interventions should be provided to those in need.

Impact of subjective sleep quality on objective measures of neurocognitive dysfunction in patients with major depressive disorder

Background

Sleep disturbances are prevalent in major depressive disorder (MDD). MDD and sleep disturbances are both linked to cognitive impairments. Studies exploring the mechanisms and impact of sleep disturbances on neurocognitive functioning in depressed patients are lacking and proper assessment and therapeutic interventions for sleep disturbances are not part of clinical management of MDD.

Aim

We investigated the association between subjective sleep quality and neurocognitive dysfunction in patients with MDD.

Materials and Methods

Patients with moderate MDD episode were matched and assigned to two groups with poor and good sleep quality. We used Pittsburgh Sleep Quality Index (PSQI) to assess sleep quality. To measure frontotemporally mediated cognitive functioning, following tests were administered: Wisconsin Card Sorting Test (WCST) and degraded continuous performance test (CPT-DS). Two-tailed independent samples t tests or Mann-Whitney U tests and Pearson's correlation coefficient were performed for the statistical analysis of sleep latency, sleep duration, overall sleep quality, CPT d' value, WCST correct answers, errors, and perseverative errors.

Results

Participants with MDD and poor sleep quality performed worse on cognitive tests compared to patients with MDD and good sleep quality. Scores of subjective sleep on PSQI positively correlated with WCST errors (r (60) =0.8883 P = .001) and negatively correlated with WCST correct answers (r (60) = -.869 P = .001) and measures of CPT-DS d' value (r (60) = -.9355 P = .001).

Conclusions

Poor sleep quality, notably sleep duration and sleep latency, worsens the neurocognitive impairments of MDD patients. As these impairments are found to be associated with treatment outcomes, sleep disturbances should be additionally assessed and treated in MDD episode.

Poor subjective sleep reported by people living with HIV is associated with impaired working memory

Poor sleep can undermine health and may be especially disruptive to those with chronic conditions including HIV infection. Here, clinically well-described people living with HIV [PLWH] (74 men, 35 women) and healthy control (38 men, 35 women) participants were administered the Pittsburgh Sleep Quality Index (PSQI), a validated measure of subjective sleep with a global score ≥5 able to distinguish good from poor sleepers. In addition, participants completed a battery of neuropsychological tests. PLWH (6.8 ± 3.7) had higher global PSQI scores than healthy controls (4.1 ± 2.8): 39.7 % of uninfected controls and 68.8 % of PLWH had a PSQI≥5 indicative of poor sleep. There were no relations between the global PSQI score and any evaluated variables among uninfected individuals or with demographic or HIV-related variables in PLWH. Instead, a higher global PSQI score among PLWH was associated with worse "Quality of Life" scores [Global Assessment of Functioning (GAF, p=0.0007), Medical Outcomes Study survey (21-item short form, SF-21, p<0.0001), and Activities of Daily Living-Instrumental (ADL-I, p=0.0041)] and higher Beck Depression Index (BDI, p<0.0001) depressive symptoms. Further, in PLWH, higher global PSQI scores were associated with poor performance on a working memory task, the digit backward span (p=0.0036). In PLWH, the 5 variables together explained 32.3 % of the global PSQI score variance; only 3 variables - the SF-21, BDI, and digit backward scores - explained 30.6 % of the variance. To the extent that poor subjective sleep contributes to impaired working memory in HIV, we speculate that this impairment may be ameliorated by improved sleep health.

Association Between Sleep and Motoric Cognitive Risk Syndrome Among Community-Dwelling Older Adults: Results From the China Health and Retirement Longitudinal Study

Background: Sleep is increasingly recognized as an important lifestyle contributor to health; however, its relationship with Motoric cognitive risk syndrome (MCR) is still unclear. The present study aimed to examine the associations between sleep duration, sleep quality, and MCR among community-dwelling Chinese older adults.

Methods: We recruited 5,387 participants aged ≥60 years from the China Health and Retirement Longitudinal Study (CHARLS). Sleep-related variables including night sleep duration and sleep quality were assessed via self-reported questionnaires. MCR syndrome was defined as cognitive complaints and slow gait speed without dementia or impaired mobility. Multivariate logistic regression analysis was performed to explore the associations between sleep-related variables and MCR after controlling for all potential confounders including demographic characteristics, lifestyle factors, and comorbidities.

Results: We found that sleep duration was significantly associated with MCR, and the multivariate-adjusted odds ratios (OR) were highest for those with the shortest (<6 h OR = 1.55, 95% CI = 1.18–2.04) and longest (≥10 h OR = 1.73, 95% CI = 1.03–2.91) sleep durations. Moreover, an increasing frequency of self-perceived poor sleep quality was significantly associated with MCR in the adjusted model (3–4 days OR = 1.58, 95% CI = 1.16–2.17; 5–7 days OR = 1.81, 95% CI = 1.37–2.40).

Conclusions: Our study indicated an inverted U-shaped association between night sleep duration and MCR. Poor sleep quality was also associated with higher odds of MCR in community-dwelling Chinese elders. Longitudinal studies with a larger population size are needed to establish causality in the future and further explore potential action mechanisms.

Shared and distinct brain fMRI response during performance of working memory tasks in adult patients with schizophrenia and major depressive disorder

Working memory (WM) impairments are common features of psychiatric disorders. A systematic meta-analysis was performed to determine common and disorder-specific brain fMRI response during performance of WM tasks in patients with SZ and patients with MDD relative to healthy controls (HC). Thirty-four published fMRI studies of WM in patients with SZ and 18 published fMRI studies of WM in patients with MDD, including relevant HC, were included in the meta-analysis. In both SZ and MDD there was common stronger fMRI response in right medial prefrontal cortex (MPFC) and bilateral anterior cingulate cortex (ACC), which are part of the default mode network (DMN). The effects were of greater magnitude in SZ than MDD, especially in prefrontal-temporal-cingulate-striatal-cerebellar regions. In addition, a disorder-specific weaker fMRI response was observed in right middle frontal gyrus (MFG) in MDD, relative to HC. For both SZ and MDD a significant correlation was observed between the severity of clinical symptoms and lateralized fMRI response relative to HC. These findings indicate that there may be common and distinct anomalies in brain function underlying deficits in WM in SZ and MDD, which may serve as a potential functional neuroimaging-based diagnostic biomarker with value in supporting clinical diagnosis, measuring illness severity and assessing the efficacy of treatments for SZ and MDD at the brain level.

Sleep quality and cognitive impairments in remitted patients with schizophrenia in Nigeria

BACKGROUND

Despite the ubiquity of sleep disturbance in schizophrenia, it has generally been overlooked as a potential contributor to cognitive impairments. The main aim of this study was to find out if impaired sleep quality contributes to cognitive impairments in patients with a diagnosis of schizophrenia who are in remission.

METHODS

The study was conducted at the University College Hospital, Ibadan and State Hospital, Ibadan, Nigeria. The Pittsburgh Sleep Quality Index (PSQI) and Screen for Cognitive Impairment in Psychiatry (SCIP) were applied in this cross-sectional study, to all consecutive and consenting remitted outpatients with schizophrenia (N=130). Other instruments such as Hamilton Depression Rating Scale (HDRS), the Positive and Negative Syndrome Scale (PANSS), sociodemographic and clinical measures were also applied.

RESULTS

There were 130 participants made up of 69 females (53.1%) and 61males(46.9%). The mean age of the participants was 38.5±9.1 years. The prevalence of poor sleep quality in remitted patients with schizophrenia was 56.9%. Sleep quality was significantly negatively correlated with Verbal Learning Test-Immediate (VLT-I) (r(128)=-.18, P=.044) and Verbal Learning Test-Delayed (VLT-D) (r(128)=-.18, P=.037). The variables that independently predicted cognitive functioning were the VLT-I, odds ratio (OR) 0.66; 95% confidence interval ((CI) 0.49-0.88) and education (OR) 0.61;(CI) 0.40- 0.92).

CONCLUSION

Poor subjective sleep quality measured by the PSQI is linked to cognitive impairment in remitted patients with schizophrenia. We suggest that sleep quality in remitted patients with a diagnosis of schizophrenia should receive better attention by physicians.

Physical Activity, Sleep-related Behaviors and Severity of Symptoms in Schizophrenia

The beneficial effects of a healthy sleep hygiene and regular physical activity have both been noted in improving psychopathology symptom severity. No study to date however, has evaluated the potential therapeutic effects of both sleep and exercise simultaneously in individuals diagnosed with schizophrenia. To examine the two variables concurrently, in the present report, patients with diagnoses of schizophrenia spectrum disorders (n = 64), were administered assessments that measured both their physical activity and sleep-related behaviors. Additionally, patients' symptom severity and cognitive and daily functioning abilities were also assessed. It was found sleep hygiene and physical activity were associated with patients' symptom severity and cognitive capacities, but not with their daily functioning abilities. Further, no interaction effects were found between sleep hygiene and physical activity. These results suggest that physical activity and sleep hygiene should be considered, independently, in their contribution to psychopathology.

Sleep and schizophrenia: From epiphenomenon to treatable causal target

BACKGROUND

Sleep disturbance is a common clinical issue for patients with psychosis. It has been identified as a putative causal factor in the onset and persistence of psychotic experiences (paranoia and hallucinations). Hence sleep disruption may be a potential treatment target to prevent the onset of psychosis and reduce persistent psychotic experiences. The aim of this review is to describe developments in understanding the nature, causal role, and treatment of sleep disruption in psychosis.

METHOD

A systematic literature search was conducted to identify studies, published in the last five years, investigating subjective sleep disruption and psychotic experiences.

RESULTS

Fifty-eight papers were identified: 37 clinical and 21 non-clinical studies. The studies were correlational (n = 38; 20 clinical, 18 non-clinical), treatment (n = 7; 1 non-clinical), qualitative accounts (n = 6 clinical), prevalence estimates (n = 5 clinical), and experimental tests (n = 2 non-clinical). Insomnia (50%) and nightmare disorder (48%) are the most prevalent sleep problems found in patients. Sleep disruption predicts the onset and persistence of psychotic experiences such as paranoia and hallucinations, with negative affect identified as a partial mediator of this relationship. Patients recognise the detrimental effects of disrupted sleep and are keen for treatment. All psychological intervention studies reported large effect size improvements in sleep and there may be modest resultant improvements in psychotic experiences.

CONCLUSIONS

Sleep disruption is a treatable clinical problem in patients with psychosis. It is important to treat in its own right but may also lessen psychotic experiences. Research is required on how this knowledge can be implemented in clinical services.

The relationship between subjective sleep quality and cognitive performance in healthy young adults: Evidence from three empirical studies

The role of subjective sleep quality in cognitive performance has gained increasing attention in recent decades. In this paper, our aim was to test the relationship between subjective sleep quality and a wide range of cognitive functions in a healthy young adult sample combined across three studies. Sleep quality was assessed by the Pittsburgh Sleep Quality Index, the Athens Insomnia Scale, and a sleep diary to capture general subjective sleep quality, and the Groningen Sleep Quality Scale to capture prior night’s sleep quality. Within cognitive functions, we tested working memory, executive functions, and several sub-processes of procedural learning. To provide more reliable results, we included robust frequentist as well as Bayesian statistical analyses. Unequivocally across all analyses, we showed that there is no association between subjective sleep quality and cognitive performance in the domains of working memory, executive functions and procedural learning in healthy young adults. Our paper can contribute to a deeper understanding of subjective sleep quality and its measures, and we discuss various factors that may affect whether associations can be observed between subjective sleep quality and cognitive performance.

The relationship between subjective sleep quality and cognitive performance in healthy young adults: Evidence from three empirical studies

The role of subjective sleep quality in cognitive performance has gained increasing attention in recent decades. In this paper, our aim was to test the relationship between subjective sleep quality and a wide range of cognitive functions in a healthy young adult sample combined across three studies. Sleep quality was assessed by the Pittsburgh Sleep Quality Index, the Athens Insomnia Scale, and a sleep diary to capture general subjective sleep quality, and the Groningen Sleep Quality Scale to capture prior night's sleep quality. Within cognitive functions, we tested working memory, executive functions, and several sub-processes of procedural learning. To provide more reliable results, we included robust frequentist as well as Bayesian statistical analyses. Unequivocally across all analyses, we showed that there is no association between subjective sleep quality and cognitive performance in the domains of working memory, executive functions and procedural learning in healthy young adults. Our paper can contribute to a deeper understanding of subjective sleep quality and its measures, and we discuss various factors that may affect whether associations can be observed between subjective sleep quality and cognitive performance.

Schizophrenia and Sleep Disorders: An Introduction

This editorial is an introduction to the special issue 'Schizophrenia and Sleep Disorders'.[…].

Neurocognitive Effects of Agomelatine Treatment in Schizophrenia Patients Suffering From Comorbid Depression: Results From the AGOPSYCH Study

BACKGROUND

Cognitive impairment in schizophrenia is highly disabling and remains one of the major therapeutic challenges. Agomelatine (AGO), an agonist at melatonergic MT1/MT2 receptors and antagonist at 5-HT2C receptors, increases dopamine and norepinephrine in the prefrontal cortex and may therefore have the potential of improving neurocognition in patients with schizophrenia.

METHODS

Twenty-seven patients with schizophrenia and comorbid depression were treated with AGO in addition to stable doses of antipsychotic drugs. Cognitive abilities were assessed with the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB) at study entry and after 12 weeks of AGO treatment after the intention-to-treat principle.

RESULTS

We observed statistically significant yet clinically negligible increases of the MCCB composite score and the reasoning/problem solving subscore. Patients with unimpaired sleep at baseline showed greater improvements over time than those with sleep disturbances. Changes on the MCCB were not correlated with other psychometric variables.

CONCLUSIONS

Despite statistically significant, cognitive improvements after 12 weeks of AGO treatment were clinically irrelevant. Our findings may be limited by baseline properties of the study sample and the study design. In particular, lacking a control group, it cannot be ruled out that improvements were unrelated to AGO treatment. That is why randomized controlled trials are needed to validate the relevance of AGO as a cognitive enhancer in schizophrenia.

Electro-acupuncture improves psychiatric symptoms, anxiety and depression in methamphetamine addicts during abstinence: A randomized controlled trial

BACKGROUND

It aimed to observe the effect of electro-acupuncture on the improvement of psychiatric symptoms, as well as anxiety and depression in methamphetamine (MA) addicts during abstinence using randomized controlled trials.

METHODS

All patients in the present study received compulsory drug detoxification in Shanghai Drug Rehabilitation Center. All patients were enrolled consecutively from June 2014 to February 2015; data collection was completed in March 2015. According to the randomized, single-blind and control principle, 68 men MA addicts were randomly divided into 2 groups: electro-acupuncture (EA) and sham electro-acupuncture (sham-EA) groups. Patients were given 20 minutes EA or sham-EA treatment every Monday, Wednesday, and Friday, with a total of 4 weeks. Positive and Negative Syndrome Scale (PANSS), Hamilton Anxiety Scale (HAMA), and Hamilton Depression Scale (HAMD) were used to evaluate the patients' psychotic symptoms, anxiety and depression before treatment and after receiving treatment with 1 to 4 weeks, respectively.

RESULTS

EA could effectively improve the symptoms of psychosis, anxiety, and depression during abstinence in patients with MA addiction. In terms of PANSS score, the scores for positive symptoms and general psychopathological symptoms in patients after receiving 1 to 4 weeks of treatment were significantly decreased compared with the control group, while the score for negative symptoms was significantly decreased after receiving 2 and 4 weeks of treatment. For the HAMA score, the psychotic anxiety scores in patients receiving 1 to 4 weeks of treatment were significant lower than the control group. In terms of HAMD score, there was a significant reduction in anxiety/somatization and sleep disturbance scores after the 4 weeks of EA treatment.

CONCLUSION

Electroacupuncture helps to improve psychiatric symptoms and anxiety and depression in MA addicts during abstinence, and promote rehabilitation of patients.

Pharmacological Treatment for Long-Term Patients with Schizophrenia and Its Effects on Sleep in Daily Clinical Practice: A Pilot Study

Background: Pharmacological treatment is still the key intervention in the disease management of long-term patients with schizophrenia; however, how it affects sleep and whether gender differences exist remains unclear. Methods: Forty-six long-term outpatients with schizophrenia entered the study. The numbers of antipsychotics, sleep medications, antidepressants, and anxiolytics were analyzed. Moreover, all patients were tested using the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Correlation analyses were conducted between the medication used and the scores on the two subjective sleep inventories. Results: A large variability, ranging from 0 to 8, in the total number of psychiatric drugs per person was found between the patients. Despite ongoing pharmacological treatment, the patients scored high on the PSQI, but not on the ESS; this indicates that they report problems with sleep, but not with daytime sleepiness. A significant positive correlation between the use of antipsychotics and the ESS score, but not the PSQI score, was found; moreover, no gender differences were found. Conclusions: A large variability exists in the pharmacological treatment of long-term patients with schizophrenia. To date, patients’ sleep problems have been insufficiently treated, and gender differences have not been adequately accounted for in the pharmacological treatment of schizophrenia. More and larger international clinical studies are warranted to verify the findings of the present preliminary pilot study before any firm conclusions can be drawn and before any changes to the drug treatment of male and female patients with schizophrenia can be recommended.

Treatment preferences and help-seeking behaviors for sleep problems among psychiatric outpatients

OBJECTIVE

To understand treatment preferences and help-seeking behaviors among psychiatric patients for their sleep problems, and to examine determinants of problem recognition and help-seeking among patients with sleep difficulties.

METHOD

A cross-sectional survey was conducted among psychiatric outpatients in Singapore (n=400). Participants completed questionnaires that assessed their sleep quality, daytime fatigue, help-seeking behavior, treatment preferences for sleep problems, and sociodemographic information. Multiple logistic regressions were used to identify correlates of patients who recognized their sleep difficulties and of those who had sought help.

RESULTS

Mental health professionals were the most preferred choice (60.8%) for consultation on sleep problems. Among patients with poor sleep quality (n=275), 28.4% denied having any problems and 38.9% had not sought help. Patients with chronic physical comorbidity were less likely to recognize their sleep problems (OR=0.432, p-value=0.009), while those with psychiatric comorbidity were twice as likely to perceive the problems (OR=2.094, p-value=0.021) and to seek help (OR=1.957, p-value=0.022). Daytime fatigue was associated with higher odds of problem recognition (OR=1.106, p-value=0.001) and help-seeking (OR=1.064, p-value=0.016).

CONCLUSION

A considerable number of patients did not perceive their poor sleep as an issue and had not sought help for it. General sleep hygiene education is needed for psychiatric patients.