## 4 Discussion  
This study revealed that a dietary supplement comprised of lemon verbena extract purified in verbascoside may help improve sleep quality and reduce stress in adolescents with sleep and stress issues. This study was conducted for 12 weeks, with significant improvements in the ASWS (for sleep) and PSS-C (for stress) questionnaires as early as during the first month of this study, compared to the placebo. This coincided with a significant reduction in cortisol levels in saliva, which is related to stress. Interestingly, a stronger effect particularly in sleep quality was perceived by the females. This has also been observed in a previous publication with the same extract [15]. Lemon verbena has been traditionally used for centuries due to its anxiolytic effects, as well as to treat various conditions, including fever, digestive discomfort, and insomnia [22]. The main active compound that is suggested to be responsible for the sleep- and stress-related properties is verbascoside [23]. Preclinical studies revealed that verbascoside binds to the benzodiazep binding site in GABA-A receptors [17; 24]. Previous clinical studies conducted with the ingredient revealed significant improvements in sleep- and stress-related parameters [15; 16]; however, these studies were conducted in an adult population. In this respect, there are fewer studies conducted in children and adolescents. Adolescence particularly is for many a challenging period, and studies have shown that up to 60% of adolescents have sleep problems [25]. The World Health Organization reports that there is a high incidence of mental disorders in adolescents, with depression, anxiety and behavioral disorders being the leading causes of illness in this population [26]. In the more severe cases, this can lead to drug and alcohol abuse, self-harm, and suicide, and the effects of mental health issues during adolescence can extend to adulthood. The COVID-19 pandemic has exacerbated this behavior [27]. Therefore, it is vital to detect early and take prevent measures to avoid lasting consequences on this vulnerable population. The current study was conducted in a single center in Italy. Studies assessing Italian children and adolescents reveal that approximately 50% sleep less than the recommended amount by the National Sleep Foundation [28]. Similar results have been observed in other countries, corroborating that poor sleep quality seems to exacerbate in this age group [29; 30; 31]. Longer screen times have been suggested to be one of the contributing factors. Besides this, studies conducted in Italy, Spain, and Portugal have revealed that there is still a lasting effect in children and adolescents from the confinement during COVID-19 [32]. Spain and Italy were more severely affected by the pandemic during the first wave, with strict confinements lasting several weeks. The referenced study reveals that children and adolescents in Italy still present significantly greater symptoms related to mood, behavior, sleep, and eating disturbances even 3 and a half years after the confinement, than compared to before the pandemic. In this study, we evaluated the subjects with questionnaires that are specifically designed for children and adolescents; the ASWS for sleep quality and the PSS-C for stress. In the case of ASWS, previous studies have shown that this questionnaire strongly correlates with the Pittsburgh Sleep Quality Index (PSQI), which is the standard questionnaire used in adults [33]. The PSS-C, on the other hand, was designed to be used in children and have been extensively used since its development a decade ago for this specific population [34]. Therefore, the use of these instruments helps to obtain more relevant information pertaining to this specific population. While the results of this study are noticeable, there are certain limitations that should be considered. For example, the low subject number caused certain parameters to lose statistical significance when analyzing the study groups based on sex.