Visual clue to schizophrenia pathology

By Eleanor McDermid, Senior medwireNews Reporter

Researchers say that retinal imaging could be a useful tool for studying some of the pathologic processes associated with schizophrenia.

A team led by Terrie Moffitt (Duke University, Durham, North Carolina, USA) studied retinal photographs taken for 922 participants in the Dunedin Multidisciplinary Health and Development Study at the age of 38 years.

They found that patients with schizophrenia had significantly wider average venular caliber than people without the condition.

“It is unclear whether venular caliber plays a causal role in the development of schizophrenia or whether it might represent an associated epiphenomenon,” the researchers write in the American Journal of Psychiatry.

But they note: “Wider venules are thought to reflect cumulative structural damage to the microvasculature and may indicate problems with the oxygen supply to the brain.”

The 27 patients with schizophrenia had significantly wider venular caliber than the cohort average after accounting for confounders. Their average caliber was also wider than that of subgroups with persistent depression or diabetes. It was increased to a similar degree to that seen among the 110 people who had hypertension, but unlike this group, schizophrenia patients did not have increased arteriole caliber.

The majority of the schizophrenia group – 70% – had a venular caliber that was above the cohort average, indicating that the group difference was not due to a few outliers.

Moffitt et al note that their findings are consistent with mounting evidence for a vascular element to schizophrenia.

Their findings also suggest that the involvement of microvasculature is not restricted to overt psychosis, as venular caliber was significantly increased among people who reported having psychotic symptoms in adulthood but did not have schizophrenia.

Furthermore, increased venular caliber was found among participants who had reported psychotic symptoms at the age of 11 years, suggesting that the association between vascular abnormalities and schizophrenia is present from an early age.

“Overall, evidence of vascular involvement in schizophrenia is accumulating, and the longstanding hypothesis of vascular pathology in schizophrenia… highlights the need for an innovative method to assess the microvasculature in living schizophrenia patients,” say the researchers.

“The noninvasive nature of retinal imaging, its relative cost-effectiveness, and the availability of the technology in primary care, optometry, and ophthalmology centers all suggest the value of retinal imaging analysis as an exciting tool for schizophrenia research.”

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