Lifetime prevalence and temporal trends of incidence of child's mental disorder diagnoses in Catalonia, Spain

Most mental disorders have its onset during childhood, but less than one third of affected children seek professional help. The aim of this study is to (1) estimate the lifetime prevalence of mood, anxiety, conduct, and eating disorder diagnoses in 18-year-olds in 2017 and (2) the temporal trends of incidence diagnosis rates in 2009–2017 in children aged 2–18 in Catalonia, Spain. We used a registry-based cohort including all children aged 2–18 living in Catalonia in 2009–2017, from the Catalan Health Service. Cases were identified with ICD-9 codes. Lifetime prevalence was calculated for 2017, and annual incidence for 2009–2017. Temporal trends were analyzed with multivariate negative binomial regression models. Lifetime prevalence of diagnoses was highest for conduct disorders (5.05%), followed by anxiety (4.37%), mood (3.07%), and eating disorders (2.11%). Median age of diagnosis was 16 years for mood, anxiety and eating disorders, and 15 years for conduct disorders. Comorbidity was present in 20.74% of those diagnosed with a mental disorder. Annual incidence rates for all disorders increased in 2011–2013/2014, and then stabilized. However, incidence rate of anxiety diagnoses in 13–18-year-old children doubled between 2016 and 2017. Lifetime prevalence of diagnoses are lower than the expected rates of mental disorders based on interview/survey European studies. Further research is needed into the factors underlying (1) the underdiagnoses of mental disorders in children and (2) the increasing trend of anxiety disorder diagnoses in older children.