Psychoneuroimmunology (PNI) in psychiatry is a dynamic interdisciplinary field concerned with the vital connections among psychological, neurological, and immune systems. This research emphasizes how psychological stress and mental disorders can significantly impact immune functions and brain processes that influence depression, anxiety, and schizophrenia. At the Psychiatry and Addiction World Conference (PAWC 2025), experts will provide PNI updates and discuss their effects on innovative therapeutic approaches to addiction and mental health. Recognition of the interaction between the immune system, brain function, and mental health paves the way for the development of novel treatments aimed at tackling the root causes of various psychiatric and addictive disorders.