Stage- and context-dependent modulation of fear memory by oxytocin: Neurobiological mechanisms and implications for PTSD.

Post-traumatic stress disorder (PTSD) is a multifactorial psychiatric condition characterized by re-experiencing, avoidance, hyperarousal, negative alterations in cognition and mood, and disturbances in social and emotional functioning. Within this broader clinical syndrome, persistent traumatic memories and excessive fear generalization represent important mechanistic and therapeutic domains. Despite substantial advances in understanding its neurobiological basis, current treatments remain suboptimal, with limited efficacy and high dropout rates. The neuropeptide oxytocin (OXT), a key modulator of social behavior, stress regulation, and memory, has been investigated as a potential therapeutic target. Accumulating evidence indicates that severe trauma profoundly disrupts endogenous OXTergic signaling, whereas pharmacological studies suggest that exogenous OXT can modulate fear-memory processing through region-, dose-, route-, and context-dependent mechanisms. Evidence from fear-conditioning indicates that across acquisition, consolidation, retrieval, reconsolidation, and extinction, the direction of OXT's effects is heterogeneous rather than uniformly anxiolytic and pro-extinction. OXT may influence threat discrimination, fear expression, memory updating, and extinction by modulating specific neural circuits and neurochemical pathways. However, most preclinical models capture selected dimensions of PTSD rather than the full clinical disorder. Human studies further indicate that intranasal OXT can modulate neural, physiological, and social-cognitive processes relevant to PTSD, although evidence for consistent clinical efficacy remains limited and heterogeneous. This review synthesizes current findings on OXT and its synthetic analogs within a stage- and context-dependent framework to better investigate their heterogeneous effects and assess their potential relevance and translational limitations in PTSD.