Infections, Inflammation, and Psychiatric Illness: Review of Postmortem Evidence

Area of Science:

• Neuroscience
• Immunology
• Psychiatry

Background:

• Epidemiological studies suggest infectious agents are linked to severe mental illnesses.
• Postmortem brain studies have not found increased microbial nucleic acid or proteins in individuals with mental illness.
• Abnormal immune and inflammatory markers are consistently observed in the postmortem brains of schizophrenia and mood disorder patients.

Purpose of the Study:

• To explore the potential role of early-life infections in the etiology and neuropathology of severe mental illnesses.
• To investigate the link between immune marker dysregulation, viral infections, and the blood-brain barrier in schizophrenia.

Main Methods:

• Review of epidemiological evidence linking infectious agents to mental illness.
• Analysis of postmortem brain studies on microbial presence and immune markers.
• Examination of immune markers implicated in schizophrenia and their potential connection to viral infections and the blood-brain barrier.

Main Results:

• No direct detection of increased microbial nucleic acid or proteins in the brains of individuals with mental illness.
• Consistent finding of abnormally expressed immune and inflammatory markers in postmortem brains of schizophrenia and mood disorder patients.
• Upregulated immune markers in schizophrenia suggest a potential role for viral infection and blood-brain barrier dysfunction.

Conclusions:

• Early-life infections may impact the developing immune system and brain neurons, contributing to severe mental illnesses.
• Immune dysregulation and potential viral involvement, alongside blood-brain barrier issues, are implicated in the neuropathology of schizophrenia.