Methods for preventing and/or treating symptoms of Post-Traumatic Stress Disorder (PTSD) are provided. The preferred method comprises administration of an effective amount of insulin to the upper one-third of a mammal's, preferably a human, nasal cavity, thereby enabling the administered at least one effective amount of insulin to bypass the patient's blood-brain barrier and be directly delivered to the patient's CNS. Another embodiment comprises utilizing vasoconstrictors to enhance targeting of an effective amount of insulin to the CNS while reducing non-target exposure.
