Brain Scans Find Shared Network Changes in Schizophrenia and Bipolar Disorder

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A new brain imaging study adds to evidence that schizophrenia and bipolar disorder overlap biologically, even though they remain distinct diagnoses. Researchers compared resting-state MRI scans from 89 people with schizophrenia, 57 people with bipolar I disorder, and 45 healthy controls. Instead of asking participants to perform a task, the researchers measured how activity in different brain regions rose and fell together while they rested. Both conditions showed lower overall synchronization between widely separated brain regions than the control group, suggesting altered coordination across brain networks. The changes were more widespread in schizophrenia, including differences involving systems linked with sensation, movement, sound, language, and face recognition. Both groups also showed altered relationships among networks involved in memory, emotion, attention, vision, and sensory processing. Importantly, functional connectivity is a measure of coordinated activity, not a picture of literal physical wiring, and the findings do not prove that these brain patterns cause either disorder. The study also cannot currently be used to diagnose an individual person. Its relatively small sample, one-time scans, different illness stages, and possible effects of medication all limit what can be concluded. Larger and longer-term studies will be needed to determine whether these patterns remain stable, change with illness, or could eventually help guide diagnosis or treatment. The broader picture is that psychiatric conditions may share some underlying biology while still producing different clinical experiences.