Trait anxiety refers to the stable tendency to attend to, experience, and report negative emotions such as fears, worries, and anxiety across many situations. This is part of the personality dimension of neuroticism versus emotional stability. Trait anxiety also manifests by repeated concerns about and reporting of body symptoms. Trait anxiety is characterized by a stable perception of environmental stimuli (events, others’ statements) as threatening. Trait-anxious people often experience and express also state anxiety, in situations in which most people do not experience such responses. This bias is thought to reflect a cognitive-perceptual bias. At the perceptual level, there is an overattentional bias to threatening stimuli. At the cognitive level, there is a distorted negative interpretation of information congruent with and fostering anxious responses. Finally, at the level of memory, there is overrecall of threatening information. These three biases are common in people with a trait-anxious personality type and have important etiological roles in various types of affective disorders (Mathews & Macleod, 2005). Trait anxiety is commonly assessed with the state-trait anxiety inventory – trait version (Spielberger, Gorsuch, & Lushene, 1970), though other instruments exist as well. Trait anxiety is an important predictor and moderator in behavior medicine. For example, trait anxiety predicts functional recovery following spine surgery, risk of posttraumatic stress disorder, as well as adaptation to and risk of death following myocardial infarction (e.g., Szekely et al., 2007). These relationships could occur since trait anxiety is related to various coping strategies and to various neurophysiological responses. For example, high trait-anxious people demonstrate greater activity in the amygdala and reduced activity in the inhibitory dorsal anterior cingulate cortex, during extinction of fear responses (Sehlmeyer et al., 2011). This brain pattern can explain their increased vulnerability for psychological disorders and adaptation problems. As such, this psychological trait deserves attention in research and clinical applications of behavior medicine. The underlying causes, mechanisms for contributing to poor health outcomes, and ways for reducing the consequences of trait anxiety are important avenues of research for the benefit of clinical practice.