105865
Not all people with PCS have abnormalities on imaging , however , and abnormalities found in studies such as fMRI , PET , and SPECT could result from other comorbid conditions such as depression , chronic pain , or posttraumatic stress disorder ( PTSD ) .
 posttraumatic stress disorder
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 posttraumatic stress disorder