Loneliness, belonging and psychosomatic complaints across late adolescence and young adulthood: a Swedish cohort study.

"Declarations Ethics approval and consent to participateThe study was approved by the Swedish Ethical Review Authority (ref. 2021-06504-01; 2022-02781-02; 2022-06502-02). According to the Swedish Ethical Review Act (2003:460), parental consent is not required for adolescents aged 15 or older if they realise what the research means for them [80]. Informed consent was obtained from all study participants. All methods were carried out in accordance with relevant guidelines and regulations. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding Open access funding provided by Stockholm University. The study was supported by the Swedish Research Council for Health, Working Life and Welfare (Forte) (grants no. 2021-00537; 2022-01050) and Region Stockholm (grant no. RS 2021-0331)."