ObjectivesMental health disorders (MHD) rank third for US adult hospitalisations. Given the substantial prevalence of ‘Long COVID’ in SARS-CoV-2 survivors, this study aims to assess its association with increased MHD risk using extensive real-world data.DesignA retrospective cohort study with propensity score matching was conducted. We used the International Classification of Diseases, 10th Revision codes to identify individuals with Long COVID status and COVID-19 histories. Multivariable stratified Cox proportional hazards regression analysis was conducted to determine the association of Long COVID status with MHD.SettingData were sourced from the TriNetX database, spanning records from 1 October 2021 to 16 April 2023.ParticipantsTwo distinct cohorts were established: one comprising individuals diagnosed with Long COVID and another comprising individuals with no history of Long COVID or COVID-19. At the start of the study, none of the participants had a recorded MHD.Primary and secondary outcome measuresThe main outcome of interest was a composite diagnosis of MHD. Secondary outcomes were individual mental health conditions.ResultsThe study included 43 060 control participants without Long COVID and 4306 Long COVID participants, demonstrating well-balanced distribution across all covariates. After adjusting for 4 demographic factors and 10 comorbidities, Long COVID was associated with MHD (adjusted HR, aHR 2.60; 95% CI 2.37 to 2.85). In subgroup analysis, Long COVID was associated with major depression disorder (aHR 3.36; 95% CI 2.82 to 4.00) and generalised anxiety disorder (aHR 3.44; 95% CI 2.99 to 3.96).ConclusionsIn this retrospective large real-world cohort study, Long COVID was associated with an increased risk of incident MHD. The MHD impact is significant considering the vast number of patients with Long COVID. Enhanced MHD screening among COVID-19 survivors should be a priority.