Background and Objective: Anxiety disorders are usually accompanied with sleep disorders. Since limited studies have focused on the effectiveness of mindfulness-based cognitive therapy (MBCT) on anxiety-related problems such as sleep disorders, the current research was conducted to investigate the effectiveness of this intervention on sleep problems.
Materials and Methods: This study was a clinical trial with control and treatment groups. The sample consisted of 24 university students diagnosed with social anxiety disorder (SAD). Social Interaction Anxiety Scale (SIAS) and Pitts-burgh Sleep Quality Index (PSQI) were used to assess the dependent variables. There were measurements during pre-test, post-test, and follow-up stages.
Results: The treatment could significantly improve the anxiety and sleeping problems in patients with social anxiety. Assessing the aspects of sleep quality showed that the intervention could improve the subjective aspects, latency, dis-turbance, and daily dysfunctions of sleep effectively; however, there was no significant effect on the duration of sleep, taking sleep medications, or sleep efficiency.
Conclusion: Mindfulness treatment could be used for improving sleep quality in patients with social anxiety. This treatment could also improve the aspects of sleep quality which are related to sleep threshold.

Background and Objective: Sleep is one of the important factors in the quality of brain function. In particular, the function of the person, learning, memory, concentration, and the potential of the individual are closely related to sleep. With regard to age and physiological changes, the average sleep time among adolescents is low. In this study, the effect of a daily nap on the promotion of academic performance of high school adolescents in Tehran, Iran, has been assessed.
Materials and Methods: In this research, 56 high school students from one of Tehran's schools with an average age of 15.3 years were volunteered. Students went to the school hall after finishing classes in the morning at 12:10, and it was 50 minutes when they were considered for their sleep. Students informed researchers with a questionnaire on the educa-tional activities outside the school.
Results: The participants showed to have an average of 2059.50 minutes after-school activity during the 2 weeks preced-ing the intervention, which reached 2388.11 minutes after the implementation of the in-school sleep program. This time was significantly higher than after-school activity time before intervention.
Conclusion: According to the results of this study, there is a significant positive correlation between daytime napping and the capacity of after-school activity in adolescents. More investigation about installing in-school sleep programs for improving educational performance in adolescents is recommended.

Background and Objective: Chronotypes vary in different people, and the daily function outside of the framework of this rhythm can affect the quality of work. This study aimed to investigate the association between sleep disorders and chronotypes among the shift and day work nurses.
Materials and Methods: This cross-sectional study was performed among nurses in two teaching hospitals in Mash-had, Iran, during 2016-2017. A total of 180 randomly-selected nurses were divided into shift work and day work groups. Participants completed demographic information form, Circadian Type Inventory (CTI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI).
Results: A total of 180 female nurses (90 participants in each group) with a mean age of 35.62 ± 4.07 years were stud-ied. The prevalence of rigid circadian rhythm in the day work group (93.3%) was significantly (P = 0.004) higher than shift work group (78.9%). However, the groups did not show any significant difference regarding the languid/vigorous (LV) index of the CTI (P = 0.080). There was a significant difference in the mean score of CTI between individuals with rigid and flexible circadian rhythms in the shift work group (P = 0.021).
Conclusion: In the present study, although there was no association between circadian type and sleep problems includ-ing insomnia and daytime sleepiness in shift work nurses, we observed the capability of coping with working in the rotating shifts in nurses with flexible circadian rhythms.

Background and Objective: Physiological process of sleep is considered as one of the influential factors of human’s health and mental functions, especially in the elderly. This research aimed at studying the association between sleep quality and the cognitive functions in the elderly population.
Materials and Methods: A total of 200 elderly people (65 years and older) who were the members of retirees associa-tion in Mashhad, Iran, participated in this cross-sectional study. The participants were asked to answer the questionnaire of Pittsburgh Sleep Quality Index (PSQI) and Montreal Cognitive Assessment (MoCA) test. Correlation between the total scores of PSQI and MoCA was evaluated by Pearson correlation coefficient. In order to predict the cognitive func-tion based on different aspects of PSQI, multiple regression analysis by hierarchical method was used after removing confounding variables.
Results: A significant association was found between PSQI and MoCA (P < 0.001, r = -0.55) suggesting that the com-ponents of use of sleeping medication (P < 0.001, r = -0.47), sleep disorders (P < 0.001, r = -0.37), sleep latency (P < 0.001, r = -0.34), subjective sleep quality (P < 0.001, r = -0.32), sleep duration (P < 0.001, r = -0.27), sleep effi-ciency (P < 0.001, r = -0.26), and daytime dysfunction (P < 0.001, r = -0.15) had significant negative correlation with cognitive function, and the four components of subjective sleep quality (P = 0.010, β = -0.15), sleep latency (P = 0.040, β = -0.13), sleep disorders (P = 0.010, β = -0.26), and use of sleeping medication (P = 0.010, β = -0.26) played a role in prediction of cognitive function in regression analysis.
Conclusion: Poor sleep quality, sleep latency, insomnia, sleep breathing disorder, and use of sleeping medication play a determining role in cognitive function of the elderly. Thus, taking care of the sleep health is necessary for the elderly.

Background and Objective: Sleep disorder and fatigue are common among health care workers (HCWs) and negative-ly affect their quality of life and caregiving to the patients. Early diagnosis and rapid modification of causative factors might prevent the potential disastrous results of these problems on personal and population health. This study aimed to evaluate the state of sleep and fatigue among HCWs of hospitals affiliated to Mazandaran University of Medical Sci-ences, Iran, and their related factors.
Materials and Methods: This cross-sectional study was conducted from September 2014 to December 2014 among HCWs at hospitals of Mazandaran University of Medical Sciences. Demographic data, medical history, and occupation-al shift information were recorded. Sleep quality was assessed by the valid and reliable Persian versions of Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI). Fatigue was evaluated by valid and reliable Persian version of Fatigue Severity Scale (FSS). Statistical analysis was performed using SPSS software.
Results: 595 HCWs participated in the study. According to ISI, 48.4% of HCWs experienced subthreshold insomnia, 25.4% were affected by moderate, and 5.0% by severe clinical insomnia. PSQI indicated poor sleep quality in 79.8% of the participants. 71.6% of HCWs had FSS of 4 or more, which was correlated to gender, age, and sleep quality. Correla-tion of sleep quality components with participants’ shift characteristics was also investigated.
Conclusion: Sleep disorders and fatigue are common in HCWs of university hospitals. Correction of certain modifiable factors can reduce negative consequences of sleep disorders and fatigue in HCWs.

Background and Objective: Obstructive sleep apnea (OSA) is a common sleep breathing disorder and a comorbid condition in patients with stroke. The prevalence of sleep disorders as a stroke consequence is high. Being independent of vascular risk factors, OSA is associated with increased risk of ischemic stroke. Here, we report a patient with OSA and stroke.
Case Report: This case report presents a patient with a history of stroke and hemiparesis who underwent polysomnog-raphy (PSG) for evaluating OSA because of snoring, witnessed apnea, and excessive daytime sleepiness (EDS). Then the subject underwent continuous positive airway pressure (CPAP) titration for treating OSA. In first night of PSG, there was a repetitive cyclic pattern of sleep and arousals. After CPAP titration study and with CPAP pressure of 15 cmH2o, OSA and rhythmic changes of electroencephalography (EEG) were resolved.
Conclusion: OSA as a risk factor for stroke can be associated with PSG cyclic wake-sleep pattern in these patients, and this pattern can be resolved by CPAP therapy.

The circadian rhythm of sleep (CRS) in humans, as an automatic biological clock, regulates the stages of sleep and wakefulness during 24 hours. However, this is not the only function of this cycle. Research shows that the CRS can play an important role in the process of energy metabolism in the body. There are also hypotheses that it affects diseases such as obesity and diabetes. Disruption of this natural rhythm can lead to metabolic imbalances in the human body and increases the risk of disorders in blood glucose regulation,blood lipids, cardiovascular system, and immune system (1, 2).

1I read with great interest the article titled ‘Tracing the relationships between sleep disturb-ances and symptoms of irritable bowel syndrome’ by Moradian Shahrbabaki et al. The authors con-ducted an interesting cross-sectional study about the correlation between irritable bowel syndrome (IBS) and sleep quality which may also apply to other sleep features.