Résumé
The pain-suicide relationship is one of the most debated in recent literature, but theories and clinical evidence have often reached contrasting conclusions. Through a critical overview of theoretical, meta-analytical and empirical contributions, we aimed at advancing the conversation on the pain-suicide relationship by integrating research on related concepts, specifically inflammation and dissociation, and their effects on interoceptive processes and pain perception.
Ideation-to-action theories consider increased pain tolerance a key risk factor for the transition from suicidal ideation to attempt. However, several meta-analytical findings suggest that suicidal thoughts and behaviors are associated with inflammation-induced pain sensitization. On the one hand, inflammation contributes to the development and maintenance of chronic pain conditions and mood disorders, and is associated with interoceptive hypervigilance and pain hypersensitivity. Moreover, a trait of increased pain tolerance does not seem to distinguish the individuals attempting suicide among those living with suicidal thoughts. On the other, temporary hypoalgesia is often activated by dissociative experiences. Highly dissociative individuals can indeed be exposed to frequent disintegration of interoceptive processes and transitory hyposensitivity to pain. In light of this, two different patterns of responses to stress (i.e. inflammation vs. dissociation) may characterize different kinds of patients at risk of suicide, associated with specific patterns of interoceptive functioning, pain sensitivity and possibly suicidal ideation. This proposition is partially supported by neuroimaging studies on post-traumatic stress disorder and psychodynamic perspectives on neurodevelopment, as well as alternative clustering models of suicidal behavior. Theoretical, meta-analytical and neurobiological evidence highlight two opposite directions in the pain-suicide relationship: hyper- vs. hyposensitivity. Such contrasts may be explained by the existence of two tendencies in stress-response, namely inflammation and dissociation, defining two different subtypes of patients at risk of suicide. We thus propose the existence of a hypersensitive subtype, defined by underlying neuroinflammatory processes, increased vulnerability to chronic pain and mood disorders, interoceptive hypervigilance, pain hypersensitivity and potentially more persistent suicidal ideation. We further hypothesize a dissociative subtype, characterized by greater trait dissociation, vulnerability to depersonalization and derealization, frequent disintegration of interoceptive processes, transient pain hyposensitivity and abrupt peaks in suicidal ideation.