Background and Objective: The optimal method of predicting mental health is the investigation of individual differences, such as identification of morning-evening types. The present study examined the relationship between components of morning-evening types, using the four components of mental health, in a group of students.
Materials and Methods: The population of this descriptive cross-sectional study was all undergraduate students at the University of Bojnord, Bojnord, Iran. The participants (N = 341) were selected from this population via stratified random sampling, and they were evaluated using the Composite Scale of Morningness (CSM) and the General Health Questionnaire-28 (GHQ-28). To analyze the data, the Pearson correlation coefficient and canonical correlation analysis (CCA) were applied.
Results: The canonical redundancy analysis showed that the first canonical function was statistically significant  (R2 = 0.205, P < 0.0001). The canonical weights showed that the order of contribution of independent variables to the first variate was morning affect (-0.921) and activity planning (-0.162), and the order of contribution of dependent variables was anxiety/insomnia (0.488), severe depression (0.350), somatic symptoms (0.198), and social dysfunction (0.179).
Conclusion: This study showed the importance of morning-evening types as the predictor of mental health and its dimensions. Therefore, it is recommended that the morningness-eveningness preferences of people be considered in clinical interviews and diagnosis. 

Background and Objective: Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder with serious consequences. The best treatment for moderate to severe OSA is continuous positive airway pressure (CPAP), and is associated with reduced OSA-related adverse consequences. However, poor adherence to CPAP is still an important issue in these patients. This study aimed to evaluate CPAP adherence, and predisposing factors for poor adherence.
Materials and Methods: In this longitudinal study, 120 patients with confirmed OSAS who underwent positive airway pressure titration study were enrolled. After at least six months of CPAP therapy, the subjects were evaluated for CPAP adherence.
Results: Of 120 participants, 40 (33.3%) used CPAP device for at least 4 hours per night in 70% of nights after at least 6 months of prescription (compliant subjects). Older age was associated with more CPAP adherence (54.3 ± 11.3 vs. 49.3 ± 12.0, P = 0.037). Patients with higher prescribed device pressure were less likely to use CPAP regularly  (8.7 ± 5.4 vs. 24.3 ± 44.2, P = 0.049). Difficult breathing and discomfort with full-face mask were the most common reported problems by compliant patients.
Conclusion: Poor adherence to CPAP therapy is a serious issue in patients with OSAS. Older age and lower CPAPdevice pressure were associated with favorable adherence. More interventions should be evaluated for improving acceptance and adherence of CPAP therapy among the patients with OSAS. 

Background and Objective: Obstructive sleep apnea (OSA) is associated with increased sympathetic activity, sleepiness, mood, and psychological alterations. In this study, mood and psychological state of patients referring to sleep laboratory were assessed.
Materials and Methods: Fifty-eight consecutive individuals eligible for participation in the study were assigned to one of two groups of normal and mild (n = 19), or moderate to severe OSA (n = 39) with apnea-hypopnea index (AHI) of ≤ 15, or > 15 per hour, respectively, based on their initial polysomnography. The mood status was evaluated using the profile of mood states (POMS).
Results: Amongst the six POMS subscales, only power-energy was significantly different between the two groups (P = 0.03). The total score of POMS, however, did not differ across the groups (P = 0.58).
Conclusion: According to the obtained results, it may be concluded that mood status and OSA are not related when POMS is used for evaluation of mood status

Background and Objective: The prevalence of snoring and sleepiness increases during pregnancy and affects maternal health and pregnancy outcomes. Therefore, this study was conducted to assess the association between snoring during pregnancy and the risk of preeclampsia.
Materials and Methods: This case-control study was performed among 150 pregnant women with preeclampsia and 150 healthy women referred to health centers and academic hospitals of Mashhad, Iran. Data collection tools included the information form regarding demographic characteristics, clinical signs, and laboratory findings. To evaluate snoring and its severity, the related question in Pittsburgh Sleep Quality Index (PSQI) was applied. Statistical analysis of data was performed by independent t-test, Mann-Whitney, chi-square test, and logistic regression model.
Results: There was significant association between snoring and preeclampsia (P < 0.001), so that the mean and standard deviation (SD) of snoring (Likert Scale of 0-3) in patients with preeclampsia was 0.6 ± 1.1, and in nonpreeclamptic women was 0.4 ± 0.9. The chance of preeclampsia in women with snoring was 1.73 times more than those without snoring [Odds ratio (OR) = 1.73, confidence interval (CI) 95%: 1.29-2.25].
Conclusion: Snoring is a predicting factor of preeclampsia. Thus, midwives and health workers' attention during pregnancy is recommended. 

Background and Objective: Sleep problems are common in school-aged children. However, despite the high prevalence, they often are overlooked. The aim of this study was to determine the frequency of sleep problems in elementary school students in Kashan, Iran.
Materials and Methods: This descriptive cross-sectional study was conducted on 300 elementary school students (7-12 years old) in Kashan City. The participants were recruited via random cluster sampling. The BEARS [B = Bedtime Issues, E = Excessive Daytime Sleepiness (EDS), A = Night Awakenings, R = Regularity and Duration of Sleep,  S = Snoring] questionnaire was completed by mothers. Data analysis was carried out by descriptive statistics [mean and standard deviation (SD)], t-test, and Mann-Whitney U test.
Results: A total of 300 students participated in the study. Of them, 44.3% (133) were boys and 55.7% (167) were girls. The most common problem was nightmare (15.7%) and resistance against wakening (21.5%). The frequency of waking up at night in boys was higher than girls (P < 0.05).
Conclusion: High frequency of sleep problems in the study indicates the importance of sleep problems in children. To promote the awareness of parents, it is necessary to give information about healthy sleep patterns through schools and parent-teacher meetings.

Background and Objective: Narcolepsy is a disorder recognized by excessive daytime sleepiness (EDS). Several studies demonstrated its association with human leukocyte antigen (HLA) DQB1*0602, DQA1*0102, and DRB1*15. Our study aimed to perform HLA-typing on patients with EDS. Moreover, we performed HLA-typing for family members of the patients.
Materials and Methods: We studied 83 patients with EDS and 77 of their first-degree relatives. Patients filled out a questionnaire including Epworth Sleepiness Scale (ESS), and underwent polysomnography (PSG) and multiple sleep latency test (MSLT). The whole blood samples were drawn from the patients and their families for HLA typing (class II). International classification of sleep disorders-2 (ICSD-2) criteria was used as the gold standard for diagnosing narcolepsy.
Results: HLA DQB1*0602 was present in 20 (45.5%) of narcoleptic patients and 2 (5.1%) of patients with other causes of EDS. Prevalence of DQB1*0602 in family members of narcoleptic patients were higher than family members of patients with other causes of EDS (38% vs. 11.1%, P = 0.06). DQB1*0602, DQA1*0102, and DRB1*15 were more prevalent in narcoleptic patients with cataplexy than narcoleptic patients without cataplexy and patients with other causes of EDS. The sensitivities of the DQB1*0602 for diagnosing narcolepsy, narcolepsy with cataplexy, and narcolepsy without cataplexy were 40%, 60%, and 20%, respectively; while specificities were 93.9%, 87.9%, and 70.6%, respectively.
Conclusion: HLA typing can be helpful in patients with atypical cataplexy and inconclusive MSLT results. More studies of Iranian narcoleptic patients are required for analyzing their HLA sequences. 

Background and Objective: Advances in molecular genetics technology has improved current understanding of the genetic causes of the rare neurological disorders with hyper-somnolence and seizure.
Case Report: An 11-year-old boy with attacks of sleepiness and hypotonicity for about 45 minutes and neurodevelopmental delay was referred to a sleep laboratory for polysomnography to rule out narcolepsy. In genetic analysis, he had mutation in the TBC1D24 gene. This mutation was heterozygous in the pair, and family members were not affected.
Conclusion: This report suggests that TBC1D24-related diseases should be considered in differential diagnosis of children with sleep attacks and seizure.

Background and Objective: Schizophrenia (SCZ) affects both genders with similar rates. It usually appears in the second to the third decades of one’s life. Schizophrenia is marked by a wide spectrum of symptoms, which functionally impair patients. The symptoms are categorized as positive, negative, or cognitive deficits. Among them, cognitive disturbance is highly valued. However, the relationship between sleep and cognition in patients with schizophrenia has been less widely considered. In this study, we aimed to review the relationship between sleep and cognition in patients with schizophrenia.
Materials and Methods: We considered selected key words (e.g. Cognition, Schizophrenia, and Sleep), and searched the online databases at the first step with defined time window of 2010 to the present; while at the second step, the incomplete knowledge was completed from 1990 to 2010. Among them, articles related to our research objectives were selected for further review.
Results: Cognitive functions including memory, attention, reasoning, decision-making, and many other elements are tightly related to quality of sleep. Moreover, sleep deficit exacerbate the symptoms of schizophrenia. It is known that cognitive function is dependent on certain activities in brain that occur during sleep. A body of research has indicated that the slow wave sleep, rapid eye movement (REM) sleep, K-complex, and also sleep spindle are at least partly explained by these functions.
Conclusion: In the light of these findings, study of brain activity via electroencephalogram (EEG) during sleep is a reasonable objective method for assessment of sleep-related cognitive markers in patients with schizophrenia.