The atrophy and laterality of the hippocampal subfields in parents with or without posttraumatic stress disorder who lost their only child in China

Abstract

Investigating hippocampal subfields may provide new and important insights into the pathophysiology of posttraumatic stress disorder (PTSD). However, no study has examined the hippocampal subfield volume changes in parents with or without PTSD who had lost their only child and could no longer conceive in China. Fifty-seven parents with PTSD (PTSD+), 11 trauma-exposed parents without PTSD (PTSD-), and 39 non-traumatized controls were recruited to examine the hippocampal subfield volumes using magnetic resonance imaging. Correlations of the volumes with the time since trauma and Clinician-Administered PTSD Scale (CAPS) scores were investigated in the PTSD+ group. The volumes of the bilateral cornu ammonis (CA) 2-3, CA4-dentate gyrus (DG), and left subiculum were significantly smaller in the PTSD+ and PTSD- groups than in the controls, but there were no significant differences between the PTSD+ and PTSD- groups. Additionally, the left CA2-3 and CA4-DG volumes reduced more than those on the right side in the PTSD+ and PTSD- groups. The subfield volumes were not related to the time since trauma and the CAPS scores in the PTSD+ group. In conclusion, hippocampal subfield volumes decreased in parents who lost their only child with or without PTSD, and the volumetric reduction may be independent of PTSD and trauma-related. Moreover, the hippocampal volume deficits showed laterality that the left side was affected more than the right, and the hippocampal subfields may show differential vulnerabilities to trauma/PTSD, with the CA2-3 and CA4-DG subfields more sensitive than others.

Alterations in hippocampal subfield and amygdala subregion volumes in posttraumatic subjects with and without posttraumatic stress disorder

“…Our results supported the notion that a smaller hippocampus is more likely to be caused by traumatic events than by PTSD itself, and a smaller hippocampus does not appear to be a preexisting risk factor for developing PTSD due to the following reasons: (a) although the volume of the hippocampus is smaller in PTSD patients when compared with HCs, this pattern was also observed in TCs, suggesting trauma contributes to volume reduction; (b) even in the hippocampal body and presubiculum, the only subfields where PTSD‐specific abnormalities were observed, the volumes of these subfields were larger in the PTSD group when compared with TCs (see discussion below: PTSD‐specific Alterations). This result is in line with some previous studies that compared recent‐onset PTSD patients with TCs (Luo et al, 2017; Winter & Irle, 2004), but not all of them (Gilbertson et al, 2002; Zhang et al, 2011). The sample size and heterogeneity of stressors could account for these discrepancies.…”

“…One study reported smaller CA1 in PTSD veterans than in TCs. Only one study recruited PTSD, TC, and healthy control (HC) subjects at the same time and compared hippocampal subfield volumes among them (Luo et al, 2017). In that study, no significant differences between patients with PTSD and TCs were found (Luo et al, 2017).…”

“…Only one study recruited PTSD, TC, and healthy control (HC) subjects at the same time and compared hippocampal subfield volumes among them (Luo et al, 2017). In that study, no significant differences between patients with PTSD and TCs were found (Luo et al, 2017). As for subregional‐level volumetric analysis of the amygdala, one recent study reported smaller lateral and paralaminar nuclei but larger central, medial and cortical nuclei in military veterans with PTSD than in veterans without PTSD (Morey et al, 2020).…”

Approach‐oriented coping strategy level may be related to volume of the whole hippocampus in the elderly

“…For instance, cross‐sectional studies have shown that PTSD is related to reductions in hippocampal volume . Additionally, individuals with psychosocial trauma showed reduced hippocampal volume . One longitudinal study showed that stressful life events reduced the volume of gray matter in the hippocampus in as little as 3 months .…”

Hippocampal subfield volumes are uniquely affected in PTSD and depression: International analysis of 31 cohorts from the PGC-ENIGMA PTSD Working Group

“…Increasing evidence suggests that the effects of stress vary across subdivisions of the hippocampus due to their unique functional and cytoarchitectural properties (35). Indeed, previous studies reported smaller volumes in subregions of the cornu ammonis (CA), CA1 (36) and CA3 (37,38), dentate gyrus (DG) (26,37), subiculum (37), and hippocampal-amygdalatransition-area (HATA) (39,40) of PTSD patients compared to controls. Hence, hippocampal volume differences in PTSD may be driven by effects in specific subregions that inform the signature of traumatic stress in the hippocampus and corresponding clinical symptoms.…”