Resting heart rate associations with violence exposure and posttraumatic stress symptoms: sex differences in children.

BACKGROUND: Traumatic events experienced in childhood can lead to increased risk of cardiovascular disorders in adulthood. Black Americans are disproportionately affected, as they are at increased risk for experiencing childhood trauma and cardiovascular diseases in adulthood. One of the hypothesized mechanisms of this association is through long-lasting dysregulation of the autonomic nervous system, a hallmark physiological biomarker of posttraumatic stress disorder (PTSD), which is twice as prevalent in women compared to men. METHODS: Ninety-one, majority Black American children, aged 9 were recruited to be a part of our longitudinal study of child development at research centers in Atlanta, GA and Detroit, MI. Resting HR was measured through a electrocardiogram (ECG) recording using the Biopac MP150. Self-report measures of violence exposure and PTSD symptoms were administered by research staff. RESULTS: Children with more violence exposure reported increased PTSS as well as lower resting HR. Regression analysis showed evidence of sex modifying this relationship, (B = -0.64, p < 0.05), such that the association between resting HR and PTSS was stronger in girls than in boys. In our exploratory analysis with standard clinical cutoffs of resting HR, the normative HR group was found to significantly moderate the relationship between violence exposure and PTSS in boys, (B = -2.14, p < 0.01), but not girls (B = -0.94, p = 0.27). CONCLUSION: In our sample of primarily Black urban children, we found that violence exposure was associated with slower, more adult-like HR, that girls showed greater PTSS associated with slower HR while boys did not, and that girls with lower than normative HR showed significantly higher PTSS compared to girls with normative HR. Our sample's demonstration of psychological consequences in addition to the physiological implications could provide new information about a psychobiological sequelae of violence exposure.

Experiencing traumatic events in childhood can lead to increased risk of heart disease in adulthood. One of the ways this might happen is through long-lasting changes of the autonomic nervous system. This system is dysregulated in posttraumatic stress disorder (PTSD), which is twice as common in women compared to men. We explored whether resting heart rate (HR), a measure of autonomic functioning was associated with violence exposure in children, and whether this relationship was different in boys and girls. We also explored whether categorizing our sample into resting HR groups based off standardized norms for HR predicted differing relationships between violence exposure and posttraumatic stress symptoms (PTSS). Because childhood trauma and heart disease impact Black Americans at greater rates, we recruited our sample of 92 nine-year-old children from research centers in Atlanta, GA and Detroit, MI. We measured their resting HR, exposure to violence, and PTSS. We found that violence exposure was associated with lower HR overall, that girls showed greater PTSS associated with lower HR when compared to boys, and that boys with lower than normative HR showed a stronger association between violence exposure and PTSS compared to boys with normative HR. Future studies should examine potential mechanisms underlying this sex difference to best understand the long-term cardiovascular consequences for sex-related health disparities. Specifically, longitudinal studies may be able to help researchers understand how reduced HR during adolescents might lead to future cardiovascular disease and psychopathology.

Associations between children's trauma-related sequelae and skin conductance captured through mobile technology.

Although many children experience trauma, few receive diagnoses and subsequent care despite experiencing trauma-related sequelae. At age nine (M = 9.11), children (N = 62; female = 46.4%) who predominantly identified as Black (78.7%) were enrolled in this first study examining how skin conductance as captured by mobile technology, eSense, related to children's traumatic experiences and trauma-related symptoms. Skin conductance measures were associated with degree of trauma exposure and PTSD hyperarousal symptoms. These findings suggest that physiological responses in addition to self-report measures may be easily used to assess children's trauma exposure and symptoms. Given eSense's ease-of-use, this technology could assist clinics and research institutions assess children's trauma-related needs.

Emotion dysregulation and dissociation contribute to decreased heart rate variability to an acute psychosocial stressor in trauma-exposed Black women.

Reduced heart rate variability (HRV) in response to stress is a biomarker of emotion dysregulation (ED) and is related to posttraumatic stress disorder (PTSD), yet less is known about its role with dissociation in trauma-exposed adults. The goals of the current study were to examine unique patterns of associations between ED, dissociation, and PTSD with HRV at 15, 30, and 45 min (T1, T2, T3) following an acute psychosocial stressor task in a sample of 49 trauma-exposed, urban-dwelling Black women. Associations with baseline psychophysiology measures were also examined. ED and dissociation were assessed using self-report; PTSD was determined using a semi-structured interview. Heart rate (HR) and HRV, indexed with low frequency/high frequency (LF/HF) ratio and respiratory sinus arrhythmia (RSA), were measured with electrocardiogram recordings. ED and dissociation were positively correlated with LF/HF ratio at T3 (p < .05). There were no significant differences between individuals with PTSD versus those without PTSD in HR or HRV following acute stressor; PTSD diagnosis was related to higher HR at baseline. Latent growth modeling revealed that ED was associated with higher LF/HF ratio directly following acute stressor, while dissociation was associated with increase in LF/HF ratio over time. These findings demonstrate that ED is related to higher sympathetic reactivity for a prolonged period of time following stress exposure, while dissociation shows a delayed association with LF/HF ratio, suggesting a distinct impaired parasympathetic activation pattern exists for dissociation.

Puberty drives fear learning during adolescence.

Risk for adverse outcomes, including the onset of mental illness, increases during adolescence. This increase may be linked to both new exposures, such as violence at home or in the community, or to physiological changes driven by puberty. There are significant sex differences in adolescent risk, for instance, anxiety disorders are significantly more prevalent in girls than boys. Fear learning is linked to mental health and may develop during adolescence, but the role of puberty in adolescent-specific change has not yet been systematically evaluated. We conducted a longitudinal study of fear learning that tested fear-potentiated startle (FPS) in 78 children (40 girls) aged 8-16 years. Participants completed two to three visits that included a differential fear conditioning task and self-report of both pubertal status and violence exposure. We tested for effects of sex, pubertal status, and violence exposure on FPS over time with latent growth curve models. We also examined the association between FPS and later anxiety symptoms. We found significant changes in FPS to the threat cue, but not the safety cue, across visits. Higher pubertal status was significantly associated with increased FPS to threat cues at each visit, whereas sex and violence exposure were not. FPS to threat during the baseline visit also predicted later anxiety symptoms. These findings suggest that puberty drives increased fear response to threat cues similarly for girls and boys, and that this effect may not be significantly impacted by individual differences in violence exposure during early adolescence.

Impact of ADCYAP1R1 genotype on longitudinal fear conditioning in children: interaction with trauma and sex.

Dysregulated fear conditioned responses have been associated with PTSD in adults, with increased fear-potentiated startle (FPS) serving as a potential intermediate phenotype for PTSD risk. This phenotype has also been associated with stress-related ADCYAP1R1 gene variants in adult women. However, FPS and genotype have not yet been examined during development. The aim of this study was to examine developmental changes in fear conditioning, and to see whether these changes were impacted by genotype and trauma. Differential fear conditioning using FPS was tested in n = 63 children ages 8-13 at two visits (V1, V2) 1 year apart. Startle response was measured using electromyograph recordings of the eyeblink muscle. The rs2267735 SNP of the ADCYAP1R1 gene was extracted from genome-wide (GWAS) analyses. Trauma exposure was assessed using the Violence Exposure Scale-Revised (VEX-R). We found significant Visit by Genotype interactions, with CC genotype increasing FPS from V1 to V2. At V2 there was a Genotype by Violence interaction, with higher FPS in the CC vs G allele groups among those with higher violence exposure (F = 17.46, p = 0.0002). Females with the CC genotype had higher FPS compared to G allele females (F = 12.09, p = 0.002); there were no effects of genotype in males. This study showed Gene × Environment × Development and Gene × Sex effects of ADCYAP1R1 in a high-risk pediatric population. Those with the CC genotype and high levels of violence exposure, as well as females with the CC genotype, showed the greatest conditioned fear responses in adolescence.