Integrated neuroimmune processing of threat, injury, and illness: An ecological framework mapping social alienation onto lifetime health vulnerability.

Social alienation is a pre-eminent ecological threat for humans. In clinical and social care settings its impact is acknowledged in conditions as diverse as severe mood disturbance, chronic pain, and metabolic non-communicable diseases. An integrated psychoneuroimmune perspective shows how threat, injury, healing, and recovery follow through as a continuous process, but accepted cultural and clinical paradigms separating mental from physical illness provide little common ground on which to analyse and apply this continuum in practice. By reviewing the ecological relationships between emotional threat, tissue dyshomeostasis and injury, infection, pain, and mood this article explores not only how primeval somatic responses underpin the evolutionary foundations of depression and somatisation, but also links them to escalating physical non-communicable disease through archived socioeconomic adversity (allostatic load). Social alienation (in the absence of trauma) may prime and activate this ancient repertoire in which sensitised responses lay the foundation for persistent maladaptive states of aversive sensory misinterpretation, behavioural avoidance, anhedonia, and neuroinflammation presenting as widespread non-nociceptive pain, non-pain somatisation, and severe depression. The ecological perspective illuminates perverse clinical presentations, shows how some approaches to care may facilitate self-reinforcement in maladaptive syndromes, and offers pointers for inclusive rehabilitative clinical and social care.