Abstract Background Obstructive sleep apnea (OSA), compromise the respiratory system during sleep. The changes involved may contribute to a negative impact on quality of life, the ability to learn, behave and being in a stable psychological state. In this respect, OSA has been found to mimic neurocognitive behavioural disorders. OSA can among physical disturbances cause cardiovascular complications, growth retardation and contributes to the metabolic syndrome. Its main aetiology in children is adenotosillar hyperplasia, being adenotonsillectomy, the preferred treatment option. However studies in the recent years have shown that the procedure does not always have the expected effect. This raises the question to whether questionnaires could elevate the level of precision in diagnosing OSA with respect to psychological changes. Method This project is an up-to date review on OSA in children and how it is related to quality of life, behavioural and emotional difficulties and neurocognitional changes. The purpose is to investigate whether adenotonsillectomy (AT) can improve the given psychological changes due to OSA and to what degree, by using polysomnography (PSG) and different questionnaires. There are also questioned whether children who have a mild form of OSA exhibit a better quality of life and if these children can profit from other forms of treatment than AT. Results The results shows large improvements in quality of life after AT, specifically in the areas of «sleep disturbance», «caregiver concerns» and «physical symptoms» which seems bee long lasting. Children with a mild form of OSA who is assigned to medical follow up seems to have the same significant improvement in the long term as children referred to the AT. There were 37 % who had behavioural problems; the most prominent were aggression, atypism (a tendency to odd and immature behaviour), depression, hyperactivity and somatisation. The strongest improvement where shown for depression, but in a moderate degree. Atypism were the only long-standing factor which did not improve. There are also shown a significant higher positive outcome after AT for restlessness, impulsitivity and hyperactivity. There were not shown any significantly improvements in attention and executive functions. Afro-Americans do have a more serious degree of OSA and a lesser degree of positive outcome after AT. The apnoè-hypopnoè index value (AHI/AI) after AT was normalized in 71-92 % of the children. There were not found any correlation between the apnoè-hypopno`index /respiratory-distress index (AHI/RDI) and the questionnaire scores. Conclusion Adenotonsillectomy leads to significant improvements in quality of sleep, quality of life and depressive symptoms. The result seems to be longstanding. No improvements are shown for attention and executive functions. The results of behavioural difficulties vary in between the different studies. The effect size is not measurable as there are too few controlled randomized trials to compare with. AHI does not correlate with subjective findings on different questionnaires and therefore it seems that AHI should not be used as a marker for the degree of OSA with respect to the change in psychological difficulties after AT. But it could be the other way around that the questionnaires are deficient. With this premises, the postoperative result might be independent of the preoperative degree of OSA, which in turn leads to the conclusion that the degree of OSA might not be related to the degree of reduction in quality of life. There should be recommended to adjust for different factors that contribute to the pathology while comparing subjective and objective measurements. The psychological difficulties in children could be secondary to OSA, and if the risk of OSA is elevated by use of questionnaires, these children should undergo PSG diagnostics for OSA. Children with mild OSA could probably be included in a watchful waiting treatment.