We first replicate a study by Vautier and Pohl (2009), who used the State–Trait Anxiety Inventory (STAI) to reexamine the structure of anxiety. Using two large samples (N = 4,138 and 1,824), we also find that state and trait anxiety measure continua that range from high calmness to high anxiety. We then significantly extend previous findings and make the clinical importance of this topic more explicit by characterizing the (linear or nonlinear) form of the relationship between the calmness–anxiety continuum and other psychiatric variables for the first time. This form is critical to understanding anxiety problems, as discontinuities in relationships with other psychological conditions could be used to define a natural boundary of problematic anxiety. Baseline levels on the calmness–anxiety continuum are found to have a near linear relationship with changes in depression, aggression, and substance misuse over time. Taken together, these results indicate the joint importance and usefulness of treating anxiety problems and promoting calmness, as doing so may promote resilience from developing other psychiatric conditions. Psychiatric and psychological interventions that are grounded in this continuum conceptualization would logically be stopped when an individual reports experiencing high levels of calmness. Our results point to the usefulness of early intervention and prevention (when people begin to move away from high calmness) and instilling resilience (by providing interventions to move people toward high calmness).