Transcranial Doppler sonography (TCD) was used to examine the mean speed of blood circulation in 50 patients suffering from post-traumatic stress disorder (PTSD). The sonography was repeated 6 months after successful psychiatric treatment. Doppler sonography of Willis's circle blood vessels and vertebrobasilar flow was performed on healthy controls as well. All of the subjects in both groups were 20 to 43 years old and had not suffered from other diseases. Vasospasm of Willis's circle blood vessels was discovered in 62% of PTSD patients, which decreased to 22% after treatment. In the control group, it occurred in 8% of subjects. TCD examination of vertebrobasilar system blood vessels did not identify significant differences in blood circulation mean speed between controls and PTSD patients, regardless of whether they had or had not been treated. This research proved the value of TCD in discovering Willis's circle blood vessel vasospasm in PTSD patients, which suggests the inclusion of TCD in diagnosing PTSD. The value of TCD was affirmed in controlling treatment success, because after 6 months of psychiatric treatment, there were significantly fewer patients with Willis's circle blood vessel vasospasm.