Defensive responses that anticipate threats have evolved as a means to ensure survival in an ever-changing world. While these responses are inherently adaptable, excessive and abnormal expression of defensive behaviors in response to potential threats can lead to pathological anxiety. This form of anxiety is not only prevalent but also debilitating, often resulting in negative outcomes. Extensive research in translational neuroscience has shown that normal defensive responses are organized based on the imminence of the threat. As such, distinct response patterns are observed in each phase of a threat encounter, orchestrated by partially conserved neural circuitry.
Anxiety symptoms, including excessive worry, physiological arousal, and avoidance behaviors, may derive from aberrant expression of these otherwise normal defensive responses. Consequently, these symptoms follow the same imminence-based organization. This review examines empirical evidence linking the specific aberrant expression of defensive responses, dependent on the imminence of the threat, to distinct anxiety symptoms. Plausible neural circuitry that contributes to these responses is also highlighted. By drawing from translational and clinical research, this proposed framework enhances our understanding of pathological anxiety. It grounds anxiety symptoms in conserved psychobiological mechanisms, allowing for a better comprehension of this complex condition.
