Childhood maltreatment and its role in the development of pain and psychopathology

Abstract

Childhood maltreatment represents a form of trauma capable of altering fundamental neurobiological properties and negatively impacting neurodevelopmental processes. An outcome of childhood maltreatment is the emergence of psychopathology, which might become evident during childhood or adolescence, but might also project into adulthood. In this Review, we propose a biobehavioural framework in which childhood maltreatment and the associated aberrant neurobiological mechanisms and behavioural processes additionally lead to the onset of altered pain processing and, ultimately, the existence of pain syndromes. Considering that subpopulations of maltreated children show preserved function and minimal psychiatric or pain symptoms, compensatory mechanisms-perhaps instilled by robust psychosocial support systems-are also discussed. We present validated tools and experimental methods that could facilitate better comprehension of the interactions between childhood maltreatment, psychopathology, and pain. Such tools and approaches can in parallel be implemented to monitor abnormal pain-related processes and potentially guide early intervention strategies in cases of childhood maltreatment.

Figure 1.. Childhood Maltreatment and its Effect on Biobehavioral Systems Implicated in Pain and Psychiatry Disorders.

During the development, distinct neurological systems mature at different rates. Neurodevelopmental mechanisms occurring at the molecular or cellular level also occur. Throughout the neurodevelopmental trajectory, and as a result of ongoing CNS maturation processes, children are arguably more vulnerable to the unfortunate and negative impact of childhood maltreatment. In the developing CNS, maltreatment is hypothesized to especially interfere with systems that regulate threat detection, fear processing, reward/anti-reward mechanisms, and other fundamental neurological properties (i.e., white matter integrity). Over time, impediment of normal neurodevelopmental process stemming from childhood maltreatment may commonly facilitate abnormal pain and somatosensory processing, psychiatric symptoms and illnesses, and complex co-morbid states. BPD: Borderline Personality Disorder; CRPS: Complex Regional Pain Syndrome; IBS: Irritable Bowel Syndrome; PTSD: Post-Traumatic Stress Disorder; SZ: Schizophrenia

Figure 2.. Altered CNS Networks Stemming from Childhood Maltreatment.

In individuals without a history of childhood maltreatment, top-down regulation within threat detection and fear processing remains intact as does normal afferent drive from the amygdala-hippocampal complex to striatal regions (A.). During or following childhood maltreatment, top-down control is compromised, while engagement of the BNST also occurs (B.). Dysregulation of reward/anti-reward circuitry caused by various forms of childhood maltreatment may also occur (C-D.). Within the proposed reward/anti-reward circuity, top-down regulation is also affected by childhood maltreatment alongside strengthened afferent signaling within mesocorticolimbic and nigrostriatal pathways. (E-F.) Abnormalities within somatosensory or pain pathways may also arise, where descending regulation of structures such as the PAG by the PFC may be disrupted. In parallel, heightened connectivity with ascending sensory and pain pathways, such as regulation of the SSC by the thalamus, is likely and may contribute to amplified pain responses or reactivity. Altered sensitivity or reactivity to other sensory modalities (e.g., visual or auditory) may implicate similar CNS networks. ACC: Anterior Cingulate Cortex; Amy: Amygdala; AI: Anterior Insula; BNST; bed nucleus of the stria terminalis; CaPu: Caudate Putamen; DH: Dorsal Horn; Hipp: Hippocampus; LC: locus coeruleus; MCC: Mid Cingulate Cortex; MI: Middle Insula; NAc: Nucleus Accumbens; OFC: Orbital Frontal Cortex; PAG: Periaqueductal Gray; PFC: Prefrontal Cortex; RVM: Rostral Ventral Medulla; SN: Substantia Nigra; SSC: Somatosensory Cortex; Thal: Thalamus; VTA: Ventral Tegmental Area.

Figure 3.. Development of Pain and Psychiatric Phenotypes.

Subsequent to or during childhood maltreatment exposure, maladaptive coping mechanisms and other risk factors (e.g., substance use, limited access to healthcare, or life adversities) may facilitate a number of CNS changes, eventually leading to pain as well as psychopathology. Conversely, exposure to maltreatment, but in the presence of resilience and other protective factors (e.g., sleep, exercise, emotion regulation interventions, social support, or access to healthcare) may mitigate the effects of childhood maltreatment. Depending on maltreatment type, duration, and developmental status of the patient, a range of the clinical phenotypes may emerge, with isolated pain or psychiatric symptoms on one end and more severe pain syndromes and psychiatric illnesses at the other end of the spectrum. While genetic predispositions on their own may yield symptoms and illnesses, a combination of genetic variants as well as epigenetic modifications, along with exposure to childhood maltreatment may, for example, increase vulnerability for the onset of pain and psychiatric disorders.