{"p"=>{"__content__"=>"Reports suggest rising trends in non-suicidal self-injury (NSSI) and disordered eating (DE) amid worsening adolescent mental health; however, the use of single-item measures obscures these findings. Moreover, there are no studies of time trends in NSSI/DE co-occurring with other mental health problems. The present study used multi-item measures to examine time trends in the prevalence of NSSI, DE, other mental health problems, and their co-occurrence in two separate school cohorts (2007/2008; 2024/2025) in the same Swedish municipality. Clinically relevant cutoffs were applied to self-report measures of NSSI (revised Deliberate Self-Harm Inventory), DE (Risk Behaviour related to Eating Disorders; girls only), and mental health problems (MHP; Strengths and Difficulties Questionnaire – self-report). Analyses included gender-stratified mixed models (time trends per outcome) and binominal generalized log-linear models (time trends in NSSI/DE×MHP concurrence). Response rates were ≈ 90% in 2007/2008 ( = 987–992; = 13.71–14.76) and ≈ 80% in 2024/2025 ( = 810–836; = 13.71–14.79). Among girls, there were threefold increases in the prevalence of repetitive NSSI and high-risk DE combined with other mental health problems (NSSI + MHP from 6.6 to 21.0%; DE + MHP from 2.7 to 8.7%). The prevalence of repetitive NSSI or high-risk DE without co-occurring mental health problems did not change. Among boys, there was no increase in repetitive NSSI with/without other mental health problems. The rising trends in the prevalence of NSSI and DE among girls indicate worsening mental health, suggesting a need for increased attention and action from the healthcare system.", "i"=>[{"__content__"=>"N"}, {"__content__"=>"M"}, {"__content__"=>"N"}, {"__content__"=>"M"}], "sub"=>[{"__content__"=>"age"}, {"__content__"=>"age"}]}}