**7. Summary of differential features**

Differential features of biomarkers specific to PTSD


Differential features of biomarkers specific to mTBI


*Biomarkers for PTSD comorbid with mTBI.* It should be apparent from the lack of conclusive biomarkers for PTSD and mTBI when occurring in isolation that there

### *Current Understanding of Biomarkers in Post Traumatic Stress Disorder and Mild Traumatic… DOI: http://dx.doi.org/10.5772/intechopen.102766*

is currently little prospect for a single biomarker that will be able to diagnose PTSD concurrent with mTBI versus detecting the presence of each condition in isolation. Part of this difficulty directly stems from the current method of diagnoses for each of these conditions. As previously discussed, although mTBI is most certainly a neurological event, it is diagnosed in a manner consistent with a psychiatric condition—based on the collection of symptoms reported. With the overlap of symptoms between both mTBI and PTSD, many of the identified biomarker candidates would be expected to be present in both PTSD and mTBI, ultimately hindering a differential diagnosis. In essence, the same conditions that necessitate the identification of a biomarker of these conditions also prevents its discovery. In addition to the necessity for larger and better designed studies, it is clear that examining the potential of any biomarker in isolation is ultimately a futile event. What may be possible in the near future is the union of several different biomarkers that are selected based on their specificity and replicability in differentially identifying PTSD and mTBI. This will require larger scale studies that collect a wide range of neuropsychological and biological samples, as well as neuroimaging, and combine them to truly accomplish these goals. In recent years there has been some progress in this regard [168, 169], at least signifying that within the field there is a recognized need and attempt to combine biomarkers not only from separate conditions, but indeed separate disciplines to discover ways to diagnose PTSD concurrent with mTBI in a more rigorous and efficient manner. This use of a collective intelligence approach, common in other fields such as finance [170], would allow for domain area expertise to identify successful candidates from what is a current, and continually growing, set of candidate biomarkers.

In summary, posttraumatic stress disorder and mTBI are both significant problems that lead to reduced quality of life for a wide range of people. Due to the nature of symptoms, diagnosis and treatment is inefficient and often delayed, resulting in additional complications in patient outcomes. Determining consistent and accurate biomarkers to improve diagnostic measures of both PTSD and mTBI as well as to differentiate between the two would improve outcomes for both disorders. In the near future, the combination of a selection of the individual biomarkers discussed could be used to design a comprehensive screening tool for individuals following a traumatic event. Additionally, identification of biomarkers involved in the transition postinjury to long-term post-concussive symptoms could allow for early intervention and prevent development of PTSD following trauma. Further, the monitoring and classification of individual responses to screening arrays could dictate the best treatment options, and inform recommendations of medication, therapies, neuromodulation techniques and various combinations from those currently available. Ultimately, this could allow patients and physicians to better direct treatment and response measures based on the individual's biological makeup.
