Sleep-disordered breathing and insomnia are common sleep disorders and associated with an increased risk of morbidity. The aim of this thesis was to study the contribution of a behavioural sleep medicine perspective on sleep-disordered breathing and insomnia. More specific, factors considered important for changing eating behaviour and the impact of physical activity were studied. Methods: In study I, semi-structured interviews of participants with obstructive sleep apnoea and obesity (n = 15) were analysed using a qualitative content analysis. A population-based female cohort was followed prospectively over ten years in study II and III using a postal questionnaire on two occasions (n = 4,851 and n = 5062, respectively). In study IV, a series of five experimental single-case studies was conducted testing how an aerobic exercise intervention affected selected typical snores, following an A1B1A2B2A3 design over nine days and nights (n = 5). Results:  Facilitators and barriers towards eating behaviour change were identified. A low level of self-reported leisure-time physical activity was a risk factor among women for future habitual snoring complaints, independent of weight, weight gain alcohol dependence or smoking. Maintaining higher levels or increasing levels of leisure-time physical activity over the ten-year period partly protected from snoring complaints (study II). Further, a low level of self-reported leisure-time physical activity is a risk factor for future insomnia among women. Maintaining higher levels or increasing levels of leisure-time physical activity over the ten-year period partly protect against self-reported insomnia, independent of psychological distress, age, change in body mass index, smoking, alcohol dependence, snoring status or level of education (study III). Single bouts of aerobic exercise did not produce an acute effect on snoring the following nights in the studied individuals. A pronounced night-to-night variation in snoring was identified (study IV). Conclusion: Women with sleep disorders would benefit from a behavioural sleep medicine perspective targeting their physical activity in the prevention and management of snoring and insomnia. This is motivated by the protective effects of physical activity confirmed by this thesis. Knowledge was added about facilitators and barriers for future eating behaviour change interventions.

Sleep disturbances and insomnia are prevalent, with around 33% of adults indicating that they experience at least one main symptom of insomnia, and bidirectional relationships exist with common psychopathology, particularly major depressive disorder (MDD). However, genetic and environmental (e.g., traumatic event exposure) contributions to the etiology of these phenotypes are not yet well understood. A genetically informative sample of approximately 12,000 Han Chinese women aged 30-60 (50% with recurrent MDD) was used to address several gaps within the sleep literature. Sleep disturbances were assessed in all individuals using a general item addressing sleeplessness (GS). A sleep within depression sum score (SDS) was also created in MDD cases, combining information from the GS and two insomnia items within MDD. A total of 11 traumatic events were assessed and additional information on childhood sexual abuse (CSA) was also obtained. First, factor analyses were conducted to determine trauma factor structure. The best-fit solution included 3 factors: interpersonal, child interpersonal, and non-assaultive, and composite variables were constructed accordingly. A series of hierarchical regressions were run to examine differential effects of trauma type and timing on sleeplessness. All traumatic events predicted sleeplessness at similar magnitudes, although population models indicated that childhood interpersonal trauma may be particularly potent. An association between CSA and sleeplessness was also replicated. A series of genetic analyses demonstrated that the single nucleotide polymorphism-based heritability of sleep phenotypes did not differ significantly from zero. Further, association analyses did not identify any genome-wide significant loci. However, using a liberal false discovery rate threshold of 0.5, two genes of interest, KCNK9 and ALDH1A2, emerged for the SDS. Polygenic risk score (PRS) analyses demonstrated genetic overlap between the SDS in MDD cases and GS in MDD controls, with PRSs explaining 0.2-0.3% of the variance. A final combined model of both genetic and environmental risk indicated that both PRS and traumatic events were significant predictors of sleeplessness. While genetic results should be interpreted with caution given the lack of heritability, additional research into the genetic and environmental contributions to insomnia, utilizing more standardized phenotypes and properly ascertained samples, is clearly warranted.

L’insomnie, une condition fréquemment retrouvée dans la population, se caractérise d’abord par une difficulté à initier ou à maintenir le sommeil et/ou par des éveils précoces le matin ou encore par un sommeil non-réparateur. Lorsqu’elle n’est pas accompagnée par des troubles psychiatriques ou médicaux ou un autre trouble de sommeil et qu’elle perdure plus de 6 mois on parle alors d’insomnie primaire chronique. Selon certains, cette condition serait associée à un état d’hyperéveil caractérisé par une augmentation de l’activité autonome sympathique durant le sommeil et l’éveil. Le baroréflexe est un important mécanisme de contrôle à court terme des fluctuations de la tension artérielle (TA) et de la fréquence cardiaque agissant sur le cœur et les vaisseaux sanguins par l’entremise du système nerveux autonome. On appelle sensibilité baroréceptive (SBR) la capacité du baroréflexe de réagir et de contrôler les fluctuations de TA en modulant le rythme cardiaque. De manière générale, la SBR serait augmentée durant la nuit par rapport à la journée. Aussi, il semblerait que le baroréflexe soit impliqué dans le phénomène de baisse physiologique de la TA pendant la nuit. Or, des données de notre laboratoire ont démontré une augmentation de la TA systolique au cours de la nuit ainsi qu’une atténuation de la baisse nocturne de TA systolique chez des sujets avec insomnie primaire chronique comparé à des témoins bons dormeurs. De plus, il a été démontré que le baroréflexe était altéré de façon précoce dans plusieurs troubles cardiovasculaires et dans l’hypertension artérielle. Or, il semblerait que l’insomnie soit accompagnée d’un risque accru de développement de l’hypertension artérielle. Ces études semblent aller dans le sens d’une altération des mécanismes de régulation de la TA dans l’insomnie. Par ailleurs, une réduction de la SBR serait aussi impliquée dans des états associés à une augmentation de l’activité autonome sympathique. Ainsi, nous nous sommes demandé si le baroréflexe pouvait constituer un des mécanismes de contrôle de la TA qui serait altéré dans l’insomnie et pourrait être impliqué dans l’augmentation de l’activité sympathique qui semble accompagner l’insomnie. Jusqu’à présent, le baroréflexe reste inexploré dans l’insomnie. L’objectif principal de ce mémoire était d’évaluer de façon non-invasive la SBR à l’éveil et en sommeil chez 11 sujets atteints d’insomnie primaire chronique comparé à 11 témoins bons dormeurs. L’évaluation du baroréflexe a été effectuée de façon spontanée par la méthode de l’analyse en séquence et par le calcul du coefficient alpha obtenu par l’analyse spectrale croisée de l’intervalle RR et de la TA systolique. De façon concomitante, les paramètres de la variabilité de l’intervalle RR en sommeil et à l’éveil ont aussi été comparés chez ces mêmes sujets. Aucune différence significative n’a été notée au niveau des index de la SBR entre le groupe d’insomniaques et celui des bons dormeurs, à l’éveil ou en sommeil. Cependant, on observe des valeurs légèrement plus faibles de la SBR chez les insomniaques ayant mal dormi (efficacité de sommeil (ES) < 85%) comparés aux insomniaques ayant bien dormi (ES≥ 85%) à la nuit expérimentale durant l’éveil et en sommeil. Par ailleurs, aucune différence n’a été notée entre le groupe d’insomniaques et celui des bons dormeurs au niveau des paramètres de la variabilité RR considérés (intervalle RR, PNN50, LF et HF en valeurs normalisées). En effet, les insomniaques tout comme les bons dormeurs semblent présenter une variation normale de l’activité autonome en sommeil, telle que représentée par les paramètres de la variabilité RR. Ces résultats préliminaires semblent suggérer que les mécanismes du baroréflexe sont préservés chez les sujets atteints d’insomnie primaire chronique tels que diagnostiqués de manière subjective. Cependant, il est possible qu’une altération des mécanismes du baroréflexe ne se révèle chez les insomniaques que lorsque les critères objectifs d’une mauvaise nuit de sommeil sont présents. / Insomnia, one of the most common sleep complaint in the general population, is characterised firstly by a difficulty initiating or maintaining sleep and/or early awakenings or non-restorative sleep. Insomnia is defined as primary when not principally due to another medical or psychiatric condition or other sleep disorder, whereas a minimum of 6 months duration is required to define chronic insomnia. Some authors have hypothesized that insomnia is associated with a state of hyperarousal characterized by increased sympathetic activity during sleep and wakefulness. The arterial baroreflex is an important mechanism providing continuous short term regulation of heart rate and blood pressure (BP) by means of the autonomic nervous system influences over the pacemaker and the peripheral circulation. Baroreflex sensitivity (BRS) is the baroreflex’s capacity to react and control BP changes by adjusting the heart rate. BRS is known to be heightened during the night compared to daytime. Also, it seems that the baroreflex could be involved in the physiological day-to-night BP fall. Previous data from our laboratory demonstrated in subjects with chronic primary insomnia, higher night-time systolic BP and a significant attenuation of the physiologic day-to-night systolic BP fall compared to good sleepers. Besides, the baroreflex has been shown to be altered early in several cardiovascular diseases and to precede hypertension. Subjects with insomnia have been shown to have a higher likelihood to develop daytime hypertension. All of these findings point in the direction of altered BP regulatory mechanisms in insomnia. Furthermore, a reduction of BRS could be implicated in states where higher sympathetic autonomic activity is observed. We hypothesised that the baroreflex could be one of the BP control mechanisms which are altered in insomnia and could be involved in the heightened sympathetic activity observed in insomnia. To our knowledge, the baroreflex has never been investigated previously in insomnia. The primary goal of this study was to investigate non-invasively BRS during wakefulness and sleep in 11 subjects with chronic primary insomnia compared to 11 good sleepers. Baroreflex was investigated spontaneously by the sequence method and by the calculation of the alpha coefficient obtained by cross spectral analysis of RR interval and systolic BP. Simultaneously, RR interval variability components were also compared during wakefulness and sleep between the two groups. No significant differences were found for indices of BRS between insomniacs and good sleepers during wakefulness and sleep. However, slightly lower values of BRS during wakefulness and sleep were noted in insomniacs with poor sleep (sleep efficiency (SE) <85%) versus those with good sleep (SE≥ 85%) at the experimental night. As a secondary finding, no differences were found between the insomniacs and the good sleepers for any of the RR variability components considered (RR interval, PNN50, LF and HF in their normalized units). Indeed, insomniacs like good sleepers exhibited normal variation of autonomic activity during sleep as depicted by the RR variability components. Our preliminary results suggest that baroreflex mechanisms are preserved in subjects with a subjective complaint of chronic primary insomnia. Nevertheless, certain impairment may occur in insomniacs as a function of objective measures of poor sleep.

No description available.

Bakgrund: Demenssjukdom är en av våra största folksjukdomar med 160 000 drabbade. Bland det vanligaste symtomet hod äldre personer med demenssjukdom är sömnbesvär. Det kan leda till ohållbar situation för den drabbade och närstående med ökad ohälsa och minskad livskvalitet som följd. Syftet med studien var att belysa sjuksköterskans erfarenhet av att vårda äldre personer med demenssjukdom som har sömnproblem. Metod Empirisk studie med beskrivande design och kvalitativ ansats. Huvudresultatet Resultatet visade sjuksköterskans erfarenhet att det var frustrerande, svårt, tids- och energikrävande att vårda äldre personer med demenssjukdom med nattlig fysisk- och psykisk oro, dygnsförvirring och tappade rutiner. Vårdpersonalens attityd, agerande, kunskap, erfarenhet och resursbrist visade på vilket sätt de bemötte och vilka val av insatser vid vård av äldre personer med demenssjukdom. Kunskap om demenssjukdomar och personkännedom var avgörande. Närstående var betydelsefulla för sjuksköterskan genom kännedom om den äldres sömnvanor och vägledning till bättre beslut. Brister framkom vid sömnobservation, bedömningar och uppföljningar av olika insatser eftersom skattningsskalor sällan användes. Läkemedel användes ofta för att främja sömnen trots kunskap om biverkningar och ökad fallrisk. Icke farmakologiska åtgärder som rekommenderades var basal omvårdnad och daglig aktivitet. Behovet av fler korttidsplatser framkom eftersom slutenvården belastades istället för att personen vårdades hemma med resurser. Tids- och planeringssystemet TES som användes i ena kommunen bidrog till sämre arbetsmiljö för omvårdnadspersonalen och påverkade personcentrerad vård negativt. Slutsats Erfarenhet, reflektion, kompetens, personkännedom och samordnade insatser från hela bårdteamet krävs för att skapa personcentrerad omvårdnad hos äldre personer med demenssjukdom som har sömnproblem.

Made available in DSpace on 2016-04-28T20:40:10Z (GMT). No. of bitstreams: 1 Marisa Vicente Catta-Preta.pdf: 1759673 bytes, checksum: 805db40ca7bdd538a0ecc796b421fd2c (MD5) Previous issue date: 2009-06-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work had as a goal to observe and analyze the dream images as a therapeutic instrument in the assistance of the treatment for patients with primary, chronic and intermediate insomnia. Group work was used in the analyses of dream reports from individuals with insomnia in fifteen meetings. The usage of remembered dreams allowed us to access to unconscious contents and from that we worked therapeutically the conflicts that were presented and that could be interfering in the insomnia. The subjects were three adults of the female sex. The choice of subjects followed the criteria of the diagnoses of chronic and intermediate insomnia, and also the criteria of availability for research, furthermore they had to remember their dreams on a regular basis. We asked the subjects to participate in an individual interview before attending the group meetings, answering questions about their sleep, dreams and also take a polysomnography so that the quality of their sleep could be analyzed. During the meetings the remembered dreams were reported and worked through with the group from the personal associations of the dreamer. Through the analyses of the dream series it was possible to present to the subjects the emotional aspects that were about an ordinary theme, which brought about a certain repetition and should be elaborated and integrated by the subject. Also, during this period, we asked the subjects to register in a diary, supplied by the researcher, the number of hours of sleep, the number of interruptions during the night, if the dream in general was good or bad and the dreams that were remembered. The method used was qualitative, and from that we analyzed the process of each subject. The data acquired was analyzed to the light of analytical psychology, following the reference of dream analyses of this approach. After the termination of the groups, the subjects took a new polysomnography in the Sleep Institute of Santos (Instituto do Sono de Santos); they did a final and individual interview with the same questions about sleep and dream. Considering the amount of hours of sleep, the quality of sleep and the individual s perception of a better quality of life as criteria for improvement, we can say that the group work with the dream images helped in the treatment of the subjects insomnia. Through the dream analyses it was possible to present the subjects the emotional aspects that were about an ordinary theme, that should be elaborated and integrated by the subject / Este trabalho teve como objetivo observar e analisar imagens oníricas como instrumento terapêutico no auxílio ao tratamento de indivíduos diagnosticados com insônia primária crônica e intermediária. Utilizou-se o trabalho em grupo para que fossem analisados sonhos de indivíduos insones durante 15 encontros. O uso de sonhos lembrados permitiu que se pudesse ter acesso a conteúdos inconscientes dos sujeitos e, a partir disso, se trabalhar terapeuticamente os conflitos apresentados que pudessem estar interferindo no quadro de insônia. Os sujeitos foram três adultos do sexo feminino. A escolha dos sujeitos seguiu o critério de terem o diagnóstico de insônia crônica e intermediária e estarem disponíveis para a pesquisa, além de lembrarem-se regularmente de seus sonhos. Foi pedido aos sujeitos que, antes de serem iniciados os encontros grupais, participassem de uma entrevista individual com a pesquisadora para responder a questões sobre seu sono e seus sonhos, e que realizassem uma polissonografia para avaliação da qualidade de seu sono. Durante os encontros, os sonhos lembrados eram relatados e trabalhados com o grupo a partir de associações pessoais do sonhador. Através da análise da série de sonhos foi possível apresentar aos sujeitos aspectos emocionais que versavam sobre um tema comum, que trazia certa repetição e deveria ser elaborado e integrado pelo sujeito. Também durante esse período pediu-se aos sujeitos que registrassem num diário, fornecido pela pesquisadora, itens que incluíam número de horas de sono, número de interrupções durante a noite, se o sono em geral fora bom ou ruim e o registro de sonhos lembrados. O método usado foi o qualitativo, a partir do qual foram feitas análises do processo de cada sujeito. Os dados obtidos foram analisados à luz da psicologia analítica, seguindo a referência de análise de sonhos dessa abordagem. Após o encerramento dos grupos, os sujeitos fizeram nova polissonografia no Instituto do Sono de Santos e uma entrevista final, individual, na qual foram reaplicadas as mesmas perguntas sobre sono e sonhos utilizadas na entrevista inicial. Considerando como critério de melhora de insônia o aumento de horas do sono, a qualidade do sono e a percepção do indivíduo de uma melhor qualidade de vida, pode-se dizer que o trabalho grupal com imagens oníricas auxiliou no tratamento da insônia dos sujeitos

Background: Insomnia is a robust correlate of suicidal ideation and behavior. Preliminary research has identified thwarted belongingness (c.f. social disconnection) as an explanatory link between insomnia and suicidal ideation. Objectives: This study replicates and extends previous findings using both cross-sectional and longitudinal designs in four demographically diverse samples. Additionally, the specificity of thwarted belongingness was evaluated by testing anxiety as a rival mediator. Method: Self-report measures of insomnia symptoms, thwarted belongingness, suicidal ideation and behavior, and anxiety were administered in four adult samples: 469 undergraduate students, 352 psychiatric outpatients, 858 firefighters, and 217 primary care patients. Results: More severe insomnia was associated with more severe thwarted belongingness and suicidality. Thwarted belongingness significantly accounted for the association between insomnia and suicidality, cross-sectionally and longitudinally, beyond anxiety. Notably, findings supported the specificity of thwarted belongingness: anxiety did not significantly mediate the association between insomnia and suicidality, and insomnia did not mediate the relation between thwarted belongingness and suicidality. Limitations: This study relied solely on self-report measures. Future studies incorporating objective sleep measurements are needed. Conclusion: Findings underscore the utility of assessing and addressing sleep disturbances and social disconnection to reduce suicide risk.

Le sommeil est un état dans lequel nous passons environ le tiers de notre vie. Il fait partie des fonctions vitales de l'organisme. Une enquête a été lancée au Liban ayant pour objectifs de connaitre les habitudes du sommeil, les styles de vie des adolescents et de découvrir les troubles de sommeil les plus fréquents et leurs facteurs associés afin de combler les lacunes dans ce domaine. 41.2% des adolescents avaient un temps de sommeil total de moins de 7 heures par nuit durant la semaine, et 34.4% surfaient sur internet avant de se coucher. 13.1% semblaient souffrir d’insomnie et 26.3% semblaient être atteints de syndrome de retard de phase (SRDP). La dépression était le facteur commun associé à ces deux troubles. En conclusion, la réalisation des études longitudinales permettant de découvrir les facteurs de risque de l’insomnie et du SRDP chez les adolescents libanais ainsi que la suggestion / We spend almost the third of our lifetime sleeping. Sleep is part of the body’s vital functions. A nationwide survey was launched in Lebanon in order to examine and evaluate the Lebanese adolescents’ sleep patterns and lifestyles and to assess the most prevalent sleep disorders and their associated factors, with the purpose of filling in the gaps in this area. 41.2% of the teenagers slept less than 7 hours per night during the week, and 34.4% once in bed always surf the internet. Insomnia and delayed sleep phase disorder (DSPD) were the most common sleep disorders among Lebanese adolescents; they had a prevalence of 13.1% and 26.3% respectively. Depression was the common factor associated with these two disorders. In conclusion, conducting longitudinal studies, in order to identify the most common risk factors of insomnia and DSPD in Lebanese adolescents and suggesting solutions to facilitate the prevention of these disorders and their risk factors are currently a must.

<p>Sömnsvårigheter hos ungdomar är ett växande problem i Sverige men det saknas forskning om behandlingsmetoder för åldersgruppen. Syftet med studien var att testa kognitiv terapi med beteendeexperiment (KT-I) på gymnasieungdomar med primär insomni. Studien genomfördes enligt en Single Subject design med för- och eftermätning. Tre ungdomar i åldern 16-18 genomgick en sju veckor lång behandling efter 1-2 veckors baslinjemätning. Resultatet visade att svårighetsgrad av insomni minskade, att funktionsförmågan dagtid förbättrades och behandlingsmålen uppfylldes i hög grad. Dagliga mätningar visade att förändring av sömnrelaterade symtom och dagtidssymtom varierade mellan deltagarna. Graden av vidmakthållande kognitiva processvariabler minskade. Slutsatser som kan dras är att KT-I är en lovande behandlingsmetod för ungdomar med insomni och att metoden bör testas ytterligare i randomiserade kontrollerade studier.</p> / <p>Sleeping difficulties are an increasing problem in Sweden for youths today, but there is a lack of research on treatments for this age group. The aim of the study was to investigate the effects from Cognitive Therapy with Behavioural Experiments (CT-I) on youths with primary insomnia in upper secondary school. The study was conducted according to a Single-Subject design with pre- and posttests. Three youths between the ages of 16-18 participated in a seven week long treatment, after 1-2 weeks of baseline measures. The results showed that the degree of insomnia decreased, that the ability to function during daytime increased, and that the treatment goals were met to a large extent. Daily measures showed that changes in sleep related symptoms and daytime symptoms varied among the participants. The degree of maintaining cognitive processes decreased. The conclusions that can be drawn are that CT-I is a promising treatment for youths with insomnia and that the method should be tested further in randomized controlled studies.</p>

<p>Sömnstörningar hos ungdomar anses vara ett växande problem. Det finns misstankar om att ungdomarnas ökade användning av Informations- och Kommunikationsteknik (IKT) är boven i dramat. Ungdomar upplevs spendera en allt större del av sin tid framför datorn, samtidigt som mobilen går varm av samtal och SMS. Det saknas dock utförlig forskning kring sambanden mellan IKT-användande och sömn. Syfte: Att undersöka huruvida ungdomar lider av sömnstörningar och om det i så fall kan kopplas till deras IKT-användande. De frågeställningar som behandlas är hur ungdomars sömnmönster ser ut och om det finns några kopplingar mellan eventuella negativa sömnmönster och deras IKT-användande. Dessutom undersöker vi om det finns några könsmässiga skillnader i sömn och IKT-användandet. Metod: Den metod som används är kvantitativ och datainsamlingen har skett genom en enkät. Urvalet består av 392 elever i årskurs ett från en gymnasieskola i västra Sverige. Enkäten besvarades och samlades in vid ett och samma tillfälle. Datan har bearbetats och analyserats i statistikprogrammet SPSS. Resultat: Analysen av resultaten visar att deltagarna har sömnproblem och att de upplever negativa effekter av dessa sömnproblem. Resultatet visar även att det finns ett samband mellan deltagarnas IKT-användande och dålig sömnkvalité, ju högre användande desto sämre sömn. Det finns inga direkta könsmässiga skillnader gällande sömnmönstret, däremot finns det skillnader gällande IKT-användandet. Slutsats: Undersökningen visar att deltagarna faktiskt lider av sömnproblem, och att användandet av IKT påverkar sömnen. Samtidigt indikerar resultatet att IKT-användning endast är en av flera påverkansfaktorer. Ytterligare forskning behövs för att till fullo förstå de bakomliggande orsakerna till ungdomarnas sömnproblem.</p> / <p>Sömnstörningar hos ungdomar anses vara ett växande problem. Det finns misstankar om att ungdomarnas ökade användning av Informations- och Kommunikationsteknik (IKT) är boven i dramat. Ungdomar upplevs spendera en allt större del av sin tid framför datorn, samtidigt som mobilen går varm av samtal och SMS. Det saknas dock utförlig forskning kring sambanden mellan IKT-användande och sömn. Syfte: Att undersöka huruvida ungdomar lider av sömnstörningar och om det i så fall kan kopplas till deras IKT-användande. De frågeställningar som behandlas är hur ungdomars sömnmönster ser ut och om det finns några kopplingar mellan eventuella negativa sömnmönster och deras IKT-användande. Dessutom undersöker vi om det finns några könsmässiga skillnader i sömn och IKT-användandet. Metod: Den metod som används är kvantitativ och datainsamlingen har skett genom en enkät. Urvalet består av 392 elever i årskurs ett från en gymnasieskola i västra Sverige. Enkäten besvarades och samlades in vid ett och samma tillfälle. Datan har bearbetats och analyserats i statistikprogrammet SPSS. Resultat: Analysen av resultaten visar att deltagarna har sömnproblem och att de upplever negativa effekter av dessa sömnproblem. Resultatet visar även att det finns ett samband mellan deltagarnas IKT-användande och dålig sömnkvalité, ju högre användande desto sämre sömn. Det finns inga direkta könsmässiga skillnader gällande sömnmönstret, däremot finns det skillnader gällande IKT-användandet. Slutsats: Undersökningen visar att deltagarna faktiskt lider av sömnproblem, och att användandet av IKT påverkar sömnen. Samtidigt indikerar resultatet att IKT-användning endast är en av flera påverkansfaktorer. Ytterligare forskning behövs för att till fullo förstå de bakomliggande orsakerna till ungdomarnas sömnproblem.</p>