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21-06-2010 | Mental health | Article

Ethnic differences found in schizophrenia brain structure

Abstract

Free abstract

MedWire News: Black patients with schizophrenia show reduced global gray matter volume compared with ethnically-matched mentally healthy controls, report UK researchers who found no such deficits in White patients.

The findings may shed light on the increased rate of psychosis in the Black community in the UK, which has been variously reported to be 2–18 times higher than in the White population.

“The reasons underlying the increased rate… are poorly understood although some have suggested that black patients are frequently misdiagnosed due to a failure of UK psychiatrists to take cultural factors into consideration,” Kevin Morgan (University of Westminster) and colleagues comment in the journal Psychological Medicine.

If this were the case one would expect more extensive structural brain abnormalities in first-episode psychosis patients who are White than in those who are Black, the researchers note.

To investigate, Morgan et al recruited 34 White British patients and 33 ethnically-matched mentally healthy controls alongside 41 African-Caribbean and Black African patients and 35 matched controls.

They scanned all patients using high-resolution magnetic resonance imaging and voxel-based morphometry image analysis.

Both White patients and Black patients with schizophrenia showed ventricular enlargement and increased lenticular nucleus volume compared with their respective ethnic controls.

Morgan et al note that increased ventricular volume is one of the most frequently found structural brain abnormalities in studies of schizophrenia.

Meanwhile, the lenticular nucleus is part of the striatum, and striatal enlargement has been reported in the early stages of psychosis following antipsychotic exposure, they add.

Contrary to their predictions, however, the researchers found that Black patients also showed reduced global gray matter and increased lingual gyrus gray-matter volume relative to the mentally healthy ethnically matched controls.

The White patients had no regional or global gray-matter loss compared with their controls, but showed increased gray matter in the left superior temporal lobe and right parahippocampal gyrus.

Explaining their findings, Morgan et al comment: “It has been suggested, for example, that stress arising from social adversity and racial discrimination may play an important role in the development and onset of psychosis in individuals with an existing biological or genetic vulnerability.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Andrew Czyzewski

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