Researchers from the New York University (NYU) School of Medicine said fewer patients would be diagnosed with post-traumatic stress disorder (PTSD) under proposed changes to diagnostic criteria for the disease. The researchers conducted a study of how the guidelines could impact PTSD diagnosis and those findings were published Monday in the journal Psychological Medicine.

The guidelines in question are the International Classification of Diseases (ICD)11, a system of medical coding, created by the World Health Organization (WHO) for documenting diagnoses, diseases, signs and symptoms, and social circumstances.

“There has been a lot of effort to try to understand what the actual implications are for diagnosis of PTSD,” Arieh Shalev, MD, the Barbara Wilson Professor in the Department of Psychiatry at NYU School of Medicine and senior author of the study, told MD+DI. “As you change diagnostic criteria 45% of those who are eligible, lose their diagnosis. There’s only about 55% overlap between samples defined by one template or the other.” The study is an examination of almost 4,000 individuals from six countries around the world and showed that changes in ICD-11 from ICD-10 could lead to a reduction in diagnosis of moderate - and more easily treatable - PTSD by as much as 57%.

The patient cohort in this research were mostly road traffic accident survivors who underwent the Clinically Administered PTSD Scale (CAPS). Researchers then compared these CAPS scores against both the existing diagnostic criteria for PTSD in ICD-10 and the revised criteria in ICD-11. The results showed that while cases of severe PTSD increased under ICD-11 by up to 36%, the number of moderate cases decreased by more than half.

In order to demonstrate the longitudinal impact of the proposed changes in ICD-11, the researchers plotted CAPS scores at different time intervals, from the actual traumatic event that triggered PTSD, up to 15 months post-event. They found that during the 0 to 60 day time interval, the prevalence of moderate PTSD in the study cohort under ICD-10 guidelines was almost 25%, but under ICD-11 guidelines, it dropped to 13%. Concomitantly, at the 122 to 456 day interval, PTSD diagnosis under ICD-10 was 14%, while under ICD-11 guidelines it dropped to 7%. Shalev said it clinicians should not solely be focused on using the guidelines.

“There is a significant effort from all sides to try and find biomarkers from brain imaging or blood tests that would assist in the diagnosis of PTSD,” Shalev said. “As you can see we are not there yet. Everyone is looking for a more subjective way to find PTSD and the body’s reaction to threat.”

Although detection isn't where it needs to be, there have been unique methods to treat PTSD, once its diagnosed. In 2016, Skip Rizzo, a clinical psychologist and associate director for medical virtual reality at the University of Southern California's Institute for Creative Technologies, has researched use of the Oculus Rift virtual reality headset in exposure therapy to help veterans overcome PTSD.