Endocannabinoid function and affective touch perception in trauma and non-trauma-exposed humans

Abstract

Touch serves an important role in social interactions, as well as regulating our stress response. In particular, C-tactile CT afferent nerve fibres facilitate the pleasant characteristics of touch and are thus thought to serve an important function as a stress buffer. However, individuals with trauma may respond differently to touch. Emerging evidence suggests that the endocannabinoid (eCB) system is involved in both stress processing and social functioning. Thus, the eCB system may influence touch processing. In study one, we looked at preferences for affective touch in individuals with documented childhood trauma (N=52) or no trauma history (N=49). We also assessed variations of the endocannabinoid ligand anandamide (AEA). In a separate study with healthy participants (N=46), we examined whether pharmacological enhancement of AEA had an impact on affective touch processing. In study one, trauma exposure was associated with marginally higher AEA levels. However, we found no significant interactions between affective touch preference and the trauma group. We observed an interaction between affective touch and AEA such that decreased preference for CT-touch was associated with higher levels of AEA. In study two, we similarly found an interaction between preference for CT-optimal touch and AEA, where the high AEA group displayed less preference for affective touch. These findings suggest that both AEA and affective touch may play a role in stress buffering. Further studies using clinical populations or conducted during stress could be informative going forward.