Objectives: The aim of this prospective longitudinal study was to evaluate the relationships between anxiety, depression, and temporomandibular disorders (TMD) in a sample of pre-university students submitted to a stressful event. Study design: 153 students from a pre-university course (82 females and 71 males between 16 and 31 years old) were given a survey about TMD symptoms and a survey about anxiety and depression scale at the beginning and the end of the preparatory course (August 2009-T1, and November 2009-T2). Results: Results were analyzed using a chi-square test and Odds Ratio (OR), significance level of á = 0.05. Statistical significance were found to depression rates in students with TMD (16% on T1 and 26% on T2, p = 0.001) as well as in general sample (12% on T1 and 22% on T2, p = 0.009), anxiety and TMD symptoms presented constant rates in both periods. Increased risk of having TMD were found in participants with anxiety (OR 2.6 in T2 and 5.6 in T1) and depression (2.0 in T2 and 3.3 in T1), but only anxiety reach statistical significance in both periods. Conclusions: TMD symptoms were a fluctuating variable that exchange between some individuals of this study. Independently of the TMD, depression rates significant increased in the evaluated period. Finally, anxiety was the psychological symptom related to the increased risk of having TMD.