Learning models for PTSD propose that classical conditioning is a key mechanism in both the development and maintenance of symptoms. In this framework, the traumatic experience itself functions as an unconditioned stimulus that naturally elicits an unconditioned response of intense fear. Cues from the environment, as well as cognitive, emotional, and physiological states associated with the trauma, become conditioned stimuli. When an individual later encounters these cues, which act as traumatic reminders, they trigger a conditioned response of fear and anxiety, similar to the reaction during the original event.