May 22, 2018
4 min read
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Proposed ICD-11 criteria may lead to fewer PTSD diagnoses

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Proposed changes to PTSD diagnostic criteria in the upcoming International Classification of Diseases-11 could result in significantly fewer PTSD diagnoses, study data indicated.

Perspective from Nils C. Westfall, MD

“The update from the 10th edition of the ICD to the upcoming 11th edition offers a particularly radical alteration,” Anna C. Barbano, research associate in the department of psychiatry, New York University School of Medicine, and colleagues wrote in Psychological Medicine.

“While the ICD-10 takes a fairly broad diagnostic approach and includes 13 symptoms in its diagnostic template, the ICD-11 proposes to remove the symptoms common to PTSD and other disorders (eg, sleep disturbances, irritability) toward increasing the specificity of the diagnosis,” they continued. “The proposed ICD-11 template comprises, therefore, six disorder-defining criteria: dissociative flashbacks, nightmares, hypervigilance, exaggerated startle response, avoidance of external reminders and avoidance of thoughts and feelings associated with the traumatic event.”

Barbano and colleagues examined differences in rates, severity and overlap of diagnoses using ICD-10 and ICD-11 PTSD diagnostic criteria made at different time intervals after trauma exposure. They compared the prevalence of PTSD according to ICD-10 and ICD-11 criteria, the overlap between samples, the severity of cases identified, differences in age and gender, presence of comorbid mood and anxiety disorders and the stability of both diagnostic groups over time for each time interval.

Using data from 11 longitudinal studies of early PTSD comprising 3,863 survivors of traumatic events, they obtained ICD-10 and ICD-11 diagnoses at two intervals after the traumatic event: 0 to 60 days (representing the early postexposure period) and 4 months to 15 months (representing persistent PTSD symptoms). Furthermore, these intervals were divided into a 22-day to 60-day period (representing an initial assessment time interval), a 4-month to 9-month period (representing an expected further recovery) and a 9-month to 15-month period (representing more chronic, stable PTSD).

Analysis revealed the ICD-11 criteria identified fewer cases compared with the ICD-10 across assessment intervals (range 47.09% to 57.14%). The prevalence was 24.89% for ICD-10 PTSD and 12.94% for ICD-11 PTSD during the 0 to 60 days interval, and participants with ICD-11 PTSD experienced higher average symptom severity score than those with ICD-10 PTSD (P < .0001). During the 4-month to 15-month interval, the prevalence was 14.1% for ICD-10 PTSD and 6.88% for ICD-11 PTSD, with the mean symptom severity scores of participants with ICD-11 PTSD again higher than that of those with ICD-10 PTSD (P < .0001). More than 97% of ICD-11 PTSD cases met concurrent ICD-10 PTSD criteria when assessed at both time intervals.

In addition, ICD-11 was linked to similar or higher rates of comorbid mood and anxiety disorders. ICD-11 cases were at higher risk for a comorbid depressive disorder than ICD-10-only cases during the 0 to 60 days interval (OR = 1.59; 95% CI, 1.14–2.22; P = .007). ICD-11 cases were also at higher risk for comorbid depressive (OR = 2.34; 95% CI, 1.16–4.76) or anxiety (OR = 2.48; 95% CI, 1.23–5.09) disorders in the 4-month to 15-month interval.

“Changes in diagnostic criteria can have significant effects on the prevalence, overlap and clinical characteristics of those identified as having a mental disorder; understanding the nature and extent of these effects is crucial for future health care provision as well as clinical and epidemiological research,” Barbano told Healio Psychiatry.

“Our data suggest that if the ICD-11 criteria are used to strictly sanction treatment coverage, fewer individuals, especially those with moderate symptoms, may have access to certain health care services,” she continued. “We suggest that clinicians be aware of the ICD-11’s tendency to identify individuals with more severe symptomology and draw from their clinical experience when treating patients post-trauma.” – by Savannah Demko

Disclosures: The authors report no relevant financial disclosures.