**4. Current methods of diagnosis and treatment options**

As stated previously, due to the overlap of symptoms in both PTSD and mTBI (**Table 1**), it is more difficult to both diagnose and treat PTSD when comorbid with mTBI. For example, in a recent study of 630,000+ veterans diagnosed with PTSD,


#### **Table 1.**

*Symptomologies of PTSD and mTBI.*

only 30% had PTSD alone, with most suffering from concurrent psychiatric conditions, of which mTBI was a prominent co-condition [69].

Diagnosis of PTSD usually consists of a combination of self-report measures and structured and/or semi-structured interview procedures. These procedures are often based on soliciting the information required to determine whether DSM-5 criteria [34] (or alternatives such as the ICD-10 [70]) have been met and include components of the trauma, symptoms/symptom clusters, and subtypes of the disorder. Common structured interviews, such as the Clinician-Administered PTSD Scale (CAPS), are considered both reliable and valid, however, they are time intensive [71]. Furthermore, due to upwards of 93% of PTSD cases co-reporting another psychiatric disorder, it can become difficult to differentiate between disorders with overlapping symptoms [6].

Unlike the diagnosis of TBI, where CT and MRI structural images readily demonstrate contusions or bleeds verifying their presence, there is a lack of interdisciplinary consensus as to what constitutes an mTBI. Although some criteria have been generally accepted (such as those described within the introduction of this chapter), there are diagnostic criteria available from the American Congress of Rehabilitation Medicine (ACRM), the US Centers for Disease Control and Prevention (CDC), and the World

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

Health Organization (WHO) [72]. Therefore, the utility of a consistent and universally accepted measure of mTBI presence would be of great benefit when diagnosing a mTBI in isolation, and especially when attempting to diagnose in the presence of the overlapping symptoms commonly reported in PTSD.

As should be apparent from this cursory examination, the current process of diagnosing both PTSD and mTBI is largely reliant on often erroneous self-report techniques and arduous clinical interviews that have an inherent lack of consensus, necessitating improvements in both speed of diagnosis and consistency to best offer care and interventions to patients with PTSD and mTBI. One such avenue of providing this information may be found through the discovery of diagnostic biomarkers, which will be the primary focus of discussion for the remainder of this chapter. Before such a discussion takes place, it is important to further highlight the need for improved methods of diagnosing comorbid mTBI and PTSD by examining the implications such discoveries may have on treatment of each condition.

Although there are recognized "gold-standard" treatments for PTSD, there is still much room for improvement. For PTSD, Cognitive Behavioral Therapy (CBT) [73] and psychopharmacological treatment with selective serotonin reuptake inhibitors (SSRIs) and/or serotonin noradrenaline reuptake inhibitors (SNRIs) are often used for treatment. Similarly, both psychological and pharmacological treatments are recommended for the treatment of mTBI, such as CBT [74] in conjunction with pharmacological treatment of the sequalae associated with mTBI [75]. However, in a recent study of the evaluations of 41 guidelines related to the treatment of mTBI, only three were founded in what was determined to be an evidenced-based fashion [76], highlighting the need for more rigorous and evidence-based treatment regimens. There is even less evidence-based guidance when it comes to the treatment of comorbid mTBI and PTSD, making research on how to best identify multimorbidity in PTSD patients critical to developing effective treatment strategies.
