What does the term 'psycho-neuro-immunology' mean and how does it relate to aromatherapy?

The Meaning of Psychoneuroimmunology

Psychoneuroimmunology (PNI) is an interdisciplinary scientific field that studies the interactions between psychological processes (such as emotions, stress, cognition), the nervous system (including the brain and nerves), and the immune system. It explores how psychological factors influence immune function through neuroendocrine pathways (e.g., the hypothalamic-pituitary-adrenal axis) and vice versa. For example, chronic stress may suppress immune responses and increase susceptibility to illness, while positive emotions may enhance immunity.

Relationship with Aromatherapy

Aromatherapy is closely related to psychoneuroimmunology, primarily through the following mechanisms:

• Action via Neural Pathways: Aromatherapy uses essential oils (such as lavender or citrus oils) to stimulate the brain's limbic system (involved in emotion and memory) through the olfactory system. This activates the hypothalamic-pituitary-adrenal (HPA) axis, thereby regulating stress responses and neuroendocrine signaling.
• Immune Modulation: Within the PNI framework, aromatherapy may indirectly influence immune system function by alleviating psychological stress (such as anxiety or depression). For instance, certain essential oil components (e.g., linalool) have been shown to reduce inflammatory markers (like cytokines) and enhance natural killer cell activity, thereby supporting overall immune health.
• Theoretical Basis: PNI provides a theoretical foundation for the efficacy of aromatherapy, explaining how it achieves mind-body benefits—such as improved sleep or enhanced resilience—through the "mind-neuro-immune axis." However, it should be noted that aromatherapy serves as a complementary therapy and is not a substitute for evidence-based medicine.