1. Introduction
he interaction between epileptic and non-epileptic seizures with sleep is complex [1]. In other words, seizure and sleep can affect each other in different ways. Many patients with seizures frequently report symptoms of sleep disorders, such as insomnia, fragmentation of sleep, and daily sleepiness [2]. Among them, excessive daytime sleepiness is one of the most frequent sleep complaints of patients. The American Psychiatric Association defines sleepiness with symptoms of excessive quantity of sleep (e.g., extended nocturnal sleep or involuntary daytime sleep), deteriorated quality of wakefulness (i.e., sleep propensity during wakefulness as shown by difficulty awakening or inability to remain awake when required), and sleep inertia (i.e., a period of impaired performance and reduced vigilance following awakening from the regular sleep episode or a nap) [3]. Various studies have different estimates of its incidence, and its prevalence has been reported in patients with seizures higher than the control group, which can lead to different psychiatric and clinical consequences [4, 5]. Among these consequences, depression, anxiety, and psychological distress are more common than other symptoms. Few studies have been conducted on the relationship between sleepiness and seizures. This study aimed to evaluate the psychological symptoms and clinical indicators resulting from the association of epileptic and non-epileptic seizures with sleepiness.
2. Methods
This research was a basic and descriptive (causal-comparative) study performed on patients with temporal lobe epilepsy, idiopathic generalized epilepsy, and psychogenic non-epileptic seizures in Namazi Hospital in Shiraz City, Iran, in 2020. A total of 68 patients were selected based on the inclusion criteria using the purposive sampling method. Then, the self-report list of demographic and clinical variables, Stanford sleepiness scale, Beck depression inventory (second edition), Beck anxiety inventory, perceived stress scale-14, the mood disorder questionnaire, the bipolar spectrum diagnostic scale, the global assessment of the severity of epilepsy, and the global assessment of disability-related directly to seizures were completed by the patients under the supervision of a clinical psychology PhD student. After collecting research data, the patients with seizures were divided into two groups with sleepiness (n=45) and no sleepiness (n=23) through a cutoff score equal to or greater than 3 on the Stanford sleepiness scale. Data obtained from patients after matching were analyzed using parametric and non-parametric tests in SPSS version 24.
3. Results
Findings from univariate analysis of covariance with variable control of the antiepileptic drugs showed that the mean scores of depression, anxiety, and stress in patients with sleepiness were significantly higher than in patients without sleepiness (P<0.05). The results of the Fisher exact test also showed a significant difference between the two groups of patients with seizures with and without sleepiness in terms of symptoms of type I and II bipolar disorder. In other words, compared to the group without sleepiness, a higher percentage of patients with sleepiness suffered from symptoms of bipolar disorder type I (31.1% vs 8.7%) and II (46.7% vs 0%) (P<0.05). Finally, the values obtained from the Mann-Whitney U test indicated that the mean severity of epilepsy and seizure-related disability in the group with sleepiness was higher than the other group (P<0.05).
4. Discussion and Conclusion
The results showed that symptoms of depression, anxiety, and stress were more frequent in patients with seizures and sleepiness than those in patients without sleepiness, and many of the patients with seizures suffered from bipolar I and II symptoms. Consistent with these findings, Erickson et al. found that more severe sleepiness increases the severity of depression and anxiety in patients with non-epileptic seizures [4]. Another study showed that excessive daily sleepiness could lead to depression in patients with epileptic seizures [6]. Although no studies have investigated the effect of sleepiness on the symptoms of bipolar disorder in these patients, it can be inferred that sleepiness can lead to maladaptive behaviors and then the development or maintenance of psychopathology in people with seizures. Some of these maladaptive behaviors are spending too much time in bed, rumination, flight of ideas, decreased concentration, constantly checking time throughout the day, irregular sleep patterns, and napping. Many of these behaviors can predispose people to mood disorders, especially the symptoms of bipolar disorder.
The findings also showed that patients with seizures with sleepiness rated their severity of epilepsy and seizure-related disability as worse than their counterparts. Kotagal and Yardi also stated in a review article that sleep disorders, especially sleepiness, can exacerbate the disease and disability resulting from seizures [7]. In this regard, sleepiness worsens the condition and disability by preventing successful control of seizures [7] and disruption of their circadian rhythms. Early evaluation, diagnosis, and treatment of sleep disorders can improve the prognosis and reduce psychiatric and clinical outcomes [5]. 
Lack of objective measurements of sleepiness, differences in the sample size of the studied groups, and self-reported nature of the data are the limitations of the present study. Future studies can complement these findings by using objective measures of sleepiness. Overall, patients with seizures and sleepiness have worse psychological and clinical consequences than patients without sleepiness.

Ethical Considerations
Compliance with ethical guidelines
The study was approved by the Research Committee of the Department of Clinical Psychology of Shiraz University and the University / Regional Ethics Committee in Biomedical Research of Shiraz University of Medical Sciences on 1/7/1398 (Code: IR.SUMS.REC.1398.784).

Funding
This article was extracted from the PhD. dissertation of the first author at the Department of Clinical Psychology, School of Education and Psychology, Shiraz University, Shiraz.

Authors' contributions
Conceptualization: Qasem Salehpour; Methodology, validation, analysis, research, sources, drafting, editing and finalization written: Qasem Salehpour, Changiz Rahimi, Noorullah Mohammadi; Visualization, project supervision and management: All authors.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
Thus, the authors of this study consider it necessary to express their gratitude to the staff of the epilepsy and seizure ward of Shiraz Namazi Hospital, as well as to all the patients who have fully assisted and cooperated in the implementation of this study.


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