08/12/2025
Several weeks ago, someone told me that diseases like schizophrenia were not real brain diseases because there were no tests for them and the diagnosis was based only on symptoms. She also said that these diseases were simply the result of choices made by individuals experiencing the symptoms.
Here is what the science says:
1. There are measurable brain differences.
Across thousands of studies, people with schizophrenia show consistent neurological findings, including:
• Changes in prefrontal cortex, temporal lobes, and hippocampus
• Differences in synaptic pruning, especially during adolescence
• Abnormalities in dopamine and glutamate signaling
• Reduced grey matter volume in specific networks
• Functional MRI showing disrupted connectivity between brain regions
These are not “symptoms”. They are biological signatures of a brain illness.
2. Schizophrenia is highly associated with genetic and immunologic factors.
• Over 200 genetic loci are linked to schizophrenia risk.
• GRIN2A and several other genes directly affect NMDA receptor function, a core brain signaling system.
• Immune dysregulation, inflammation, and infection during early development are known contributors.
This is consistent with a complex brain disease, not a behavioral choice.
3. Early psychosis programs routinely document measurable neurological changes.
Cognitive impairments, slowed processing speed, impaired working memory, and executive dysfunction are objective findings that cannot be faked and have biological underpinnings.
4. Antipsychotic medications work by acting on brain receptors.
These medications target dopamine, glutamate, and serotonin systems. If schizophrenia were not a brain-based illness, they wouldn’t work.
5. Symptom-based diagnosis is normal for complex brain illnesses.
Schizophrenia is diagnosed based on symptoms because the brain is extraordinarily complex, not because the disease isn’t real.
diagnoses like :
• Parkinson’s disease by tremor + rigidity + gait changes
• Multiple sclerosis by relapses + neurological symptoms
• Migraine by symptom pattern
• Autism by symptoms and behavior
• Major depression by symptoms
• Dementia by cognitive symptoms
No one claims those are “not real diseases.”
Schizophrenia is no different.
