This systematic review synthesizes how the life cycles and circadian rhythms of central immune (glial) cells affect functions like phagocytosis, immune clearance, neurogenesis, neurotransmitter recycling, and how these rhythmic processes relate to neuropsychiatric and neurodegenerative diseases…

It highlights glial circadian regulation of neuroinflammation, oxidative stress, and sleep-related processes that are relevant to Parkinson's therapeutic timing and glia-targeted strategies, but remains a broad review with limited direct, actionable targets for immediate drug discovery.

The central resident immune system, commonly known as the glial system, comprises various glial cells that play a critical role in neuropsychiatric disorders. However, a systematic review exploring the relationships between the life cycles and daily rhythms of these immune cells and the pathological features of neuropsychiatric disorders is lacking. These immune cells exhibit unique developmental origins and circadian characteristics, resulting in rhythmic variations in functions such as phagocytosis, immune clearance, neurogenesis, and neurotransmitter recycling. These properties are crucial for understanding the pathological mechanisms underlying developmental disorders like major depressive disorder, autism spectrum disorder, and schizophrenia, as well as age-related conditions such as Alzheimer's and Parkinson's diseases. The daily rhythms of these immune cells correlate with diurnal variations in emotion, cognition, and motor function, involving shared processes like oxidative stress and neuroinflammation. This article systematically reviews the composition, life cycle changes, and circadian characteristics of central immune cells, highlighting their roles in neuropsychiatric diseases.