PTSD Emotional Numbing Impacts Intensity of Neutral to Negative State Shifts

Nachshon Korem, PhD

Credit: Yale School of Medicine

People suffering from PTSD experience abrupt transitions between neutral and negative emotional states, with the magnitude of this shift escalating depending on the severity of the emotional numbing symptoms, a new study found.¹

“These preliminary results provide valuable insights into the complex association between emotional processing and PTSD symptoms,” wrote investigators, led by Nachshon Korem, PhD, from the department of psychiatry at Yale University School of Medicine.

PTSD is characterized as experiencing contrasting symptoms of hyperemotional reactivity (neutral state) and emotional numbing (negative state). Although emotional numbing is considered to restrict positive emotions, it is also suggested to limit negative emotions, too.² Alongside emotional numbing, many symptoms of PTSD are associated with hyperactivity to emotional stimuli.

In their cross-sectional study, investigators sought to explore whether individuals grappling with PTSD encountered a significant shift from neutral to negative emotional states and how the emotional numbing severity influences the transition.¹

From January 17 to March 8, 2023, the team recruited trauma-exposed individuals who either witnessed or experienced a life-threatening incident, violent assault, or someone being killed. Participants completed the PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM-5). They were considered to have PTSD if they had a PCL-5 score of ≥ 33 and had ≥ 1 intrusion symptom, 1 avoidance symptom, 2 negative alterations in cognition and mood symptoms, and 2 alterations in arousal and reactivity symptoms.

The study included 1440 trauma-exposed individuals who either were probable PTSD (n = 445) or trauma-exposed controls. The PTSD group leaned younger with a mean age of 36.1 years than the controls with a mean age of 41.5 years (P < .001).

The sample was made up of mostly White participants (75.3%, followed by African American or Black (7.4%), Multiracial (5.5%), Asian (4.6%), other race (1.6%), preferred not to say (0.7%), and American Indian or Alaska Native (0.6 %). The study included 47.6% of females, and the groups had similar sex distributions, with 230 women in the PTSD group and 427 in the control group (P = .67).

Investigators analyzed PTSD emotions using hierarchical Bayesian modeling in the logistic regression to analyze the valence ratings of 40 images. The images included stimuli, featuring faces, people, and animals. The team aimed to compare the curve’s slope between groups and explore the association between the slope and the severity of emotional numbing symptoms.

The primary outcome was the slope parameter derived from the logistic curve fitted to the valence rating. The slope parameter represented the rate at which emotional response intensity alters with stimulus valence, indicating the transition speed between neutral and negative valence states.

Overall, the PTSD group demonstrated a steeper slope than the controls (mean slope difference, -0.255; 89% highest posterior density [HPD], -0.340 to -0.171), indicating a sharper transition. Investigators observed a strong association between the slope and emotional numbing severity (mean additive value, 0.100; 89% HPD, 0.051 – 0.15). After controlling for age, emotional numbing was still associated with transition sharpness (additive value, 0.108; 89% HPD, 0.056 – 0.159) without an age-related association (additive value, 0.031; 89% HPD, -0.022 to 0.083).

The team outlined several limitations including potential data manipulation of lower data quality due to using online studies, the age differences between the 2 groups, not collecting data on index trauma, trauma load, childhood trauma, and time since trauma, and using non-trauma-specific images.

“This study advances our understanding of emotional processing in PTSD by focusing on the transitional dynamics between neutral and negative emotional states, a facet often overlooked in traditional research,” investigators concluded. “These transitional dynamics’ robust association with the severity of emotional numbing symptoms extends the prevailing understanding of emotional experiences in PTSD beyond intensity metrics. The steeper slope in emotional transitions holds notable clinical implications, directing attention toward developing targeted interventions that focus on emotion regulation.”

References

Korem, N, Duek, O, Spiller, T. Emotional State Transitions in Trauma-Exposed Individuals With and Without Posttraumatic Stress Disorder. JAMA Network Open. 2024;7(4):e246813. doi:10.1001/jamanetworkopen.2024.6813 (Reprinted)

Emotional Numbness in PTSD & C-PTSD. PTSDUK. https://www.ptsduk.org/emotional-numbness/. Accessed April 16, 2024.