In anxiety disorders, approach-avoidance behavior is typically biased towards excessive, maladaptive avoidance despite costs and impairments (i.e., costly avoidance). Yet, little is known about the underlying decision dynamics that may contribute to such imbalanced behavior. The current study tested for altered temporal decision dynamics in patients with anxiety disorders compared to matched healthy controls in a task where avoiding an aversive stimulus conflicted with obtaining rewards. Participants chose repeatedly between a fixed safe/low reward and a threat/high reward option with varying threat (probability of an aversive stimulus presentation) and reward information (reward magnitude). Structured computer mouse movements required for choosing between options were tracked to capture the temporal dynamics of the decision process (i.e., when and how strongly threat and reward information influenced decision preference). The current study replicated elevated costly threat avoidance in patients with anxiety disorders compared to matched controls. Importantly, time-continuous multiple regression of mouse movements revealed altered temporal dynamics: patients showed a faster (but not stronger) impact of threat and a weaker impact of competing rewards. These findings highlight that not only biases in threat processes but also competing rewards may guide excessive avoidance and could be important treatment targets in anxiety disorders. Future research may support the external validity of these findings in real-life decisions and try to identify therapeutic strategies that allow to specifically target the attenuated impact of rewards and the accelerated impact of threat in patients.