Objectives: To induce disease remission, early arthritis patients should adhere to their disease-modifying antirheumatic drugs (DMARD) in the first months after diagnosis. It remains unknown why some patients are non-adherent. We aimed to identify patients at risk for non-adherence in the first 3 months of treatment. Methods: Adult DMARD-naive early arthritis patients starting synthetic DMARDs filled out items on potential adherence predictors at baseline. Adherence was measured continuously. Non-adherence was defined as not opening the electronically monitored pill bottle when it should have been. Items were reduced and clustered using principal component analysis. The most discriminating items were identified with latent trait models. We used a multivariable logistic regression model to find non-adherence predictors. Results: 301 patients agreed to participate. Adherence was high and declined over time. Principal component analysis led to 7 dimensions, while subsequent latent trait models analyses led to 15 dimensions. Two dimensions were associated with adherence, one dimension was associated with nonadherence. Conclusions: Information seeking behavior and positive expectations about the course of the disease are associated with adherence. Patients who become passive because of pain are at risk for non-adherence. Practice implications: Rheumatologists have cues to identify non-adherence, and may intervene on nonadherence through implementing shared decision making techniques. (C) 2016 Elsevier Ireland Ltd. All rights reserved.