The present invention provides for methods of measuring levels of micro RNAs for the diagnosis, treatment and/or monitoring the progression of post-traumatic stress disorder (PTSD) or traumatic brain injury (TBI) in a subject having or suspected of having PTSD and/or TBI. The methods, in general comprise measuring levels of at least one of miR-142-5p, miR-19b, miR-1928, miR-223-3p, miR-322*, miR-324, miR-421-3p, miR-463* and miR-674* is a sample from a subject suffering from or suspected of having PTSD and/or TBI.