In the nearly a quarter of a century since the addition of the clinically significant distress/impairment criterion to the definition of PTSD in DSM-IV, little research has been done to examine the association of this criterion with symptom group criteria and with the numbing subgroup specifically. This study was conducted to examine these relationships in a large database of disaster survivors consistently studied across 12 different incidents of the full range of disaster typology.

Analysis was conducted on a merged database representing 1187 trauma-exposed survivors of 12 different disasters studied systematically. DSM-IV-TR criteria for disaster-related PTSD were assessed with the Diagnostic Interview Schedule.

PTSD Group C (avoidance/numbing) and numbing specifically were less common and more associated than other symptom groups with criterion F (distress/impairment). Consistently in multivariable models, group C and numbing were independently associated with criterion F. Group D (hyperarousal) was less strongly associated with criterion F. Neither group B (intrusion) nor avoidance were associated with criterion F.

In this and other studies, group C and numbing specifically have been shown to be associated with criterion F, which is consistent with the demonstration that group C and the numbing component specifically are central to the psychopathology of PTSD. The addition of the distress/impairment requirement broadly across the psychiatric diagnoses in DSM-IV added little value to PTSD symptom criteria. Future revisions of diagnostic criteria may benefit by carefully considering these findings to possibly re-include a prominent numbing symptom section.

Cognitive processing therapy (CPT) is an effective treatment for posttraumatic stress disorder (PTSD), including for veterans with military sexual trauma (MST)-related PTSD. Most CPT research to date has focused on pre- to post-treatment change in total PTSD symptoms; however, PTSD symptom criteria may not change equivalently over the course of treatment. For example, changes in re-experiencing symptoms have been shown to precede changes in other PTSD criteria during other PTSD treatments (i.e. virtual reality exposure therapy, venlafaxine ER). An improved understanding of the mechanism of change in PTSD symptoms during CPT may assist in optimizing treatment.

The purpose of this study was to identify the pattern and temporal precedence of change in PTSD symptom criteria during and after CPT using cross-lagged panel analyses.

Data from veterans (n = 32) enrolled in a randomized clinical trial investigating the effectiveness of CPT for MST-related PTSD were utilized for this secondary analysis. Using hierarchical linear modelling, each symptom criterion was entered as a predictor of subsequent change in the other PTSD symptom criteria.

All symptom criteria followed a logarithmic pattern of change. Hyperarousal symptoms were found to both predict and temporally precede change in avoidance symptoms, but not re-experiencing symptoms. Re-experiencing and avoidance symptoms did not predict change in other PTSD symptom criteria.

These findings provide initial support that targeting and reducing hyperarousal symptoms may be a key component of PTSD intervention with CPT. Additional research is needed to identify factors that predict change in PTSD-related re-experiencing symptoms.

Previous research in post-traumatic stress disorder (PTSD) has identified disrupted ventromedial prefrontal cortex (vmPFC) function in those with v. without PTSD. It is unclear whether this brain region is uniformly affected in all individuals with PTSD, or whether vmPFC dysfunction is related to individual differences in discrete features of this heterogeneous disorder.

In a sample of 51 male veterans of Operation Enduring Freedom/Operation Iraqi Freedom, we collected functional magnetic resonance imaging data during a novel threat anticipation task with crossed factors of threat condition and temporal unpredictability. Voxelwise regression analyses related anticipatory brain activation to individual differences in overall PTSD symptom severity, as well as individual differences in discrete symptom subscales (re-experiencing, emotional numbing/avoidance, and hyperarousal).

The vmPFC showed greater anticipatory responses for safety relative to threat, driven primarily by deactivation during threat anticipation. During unpredictable threat anticipation, increased PTSD symptoms were associated with relatively greater activation for threat v. safety. However, simultaneous regression on individual symptom subscales demonstrated that this effect was driven specifically by individual differences in hyperarousal symptoms. Furthermore, this analysis revealed an additional, anatomically distinct region of the vmPFC in which re-experiencing symptoms were associated with greater activation during threat anticipation.

Increased anticipatory responses to unpredictable threat in distinct vmPFC subregions were uniquely associated with elevated hyperarousal and re-experiencing symptoms in combat veterans. These results underscore the disruptive impact of uncertainty for veterans, and suggest that investigating individual differences in discrete aspects of PTSD may advance our understanding of underlying neurobiological mechanisms.