Recollection shows endophenotype potential in schizophrenia
MedWire News: Schizophrenia patients show memory deficits in both familiarity and recollection whereas their parents have deficits only in recollection, the results of a Canadian study indicate.
Episodic memory deficits have been demonstrated in both schizophrenia patients and their unaffected relatives and are considered to be an indicator of genetic vulnerability to the disorder. However, the relative contribution of familiarity and recollection has not been examined.
Andrée-Anne Lefèbvre, from Centre de Recherche Université Laval Robert-Giffard, in Québec, and colleagues therefore studied 26 schizophrenia patients and 35 of their unaffected parents, comparing them with 26 healthy controls and 35 of their healthy parents.
In order to separate the contribution of familiarity and recollection processes to episodic memory deficits, the team administered an item-spatial context association task and an item-item association task.
Compared with their controls, patients performed significantly worse on the item-spatial context task. Interestingly, the reduced performance was not due to a specific memory task, but rather an overall reduced performance.
While unaffected parents did not perform worse overall than their controls on the item-spatial context task, they did perform significantly worse on the location aspect of the task, but not on the item or relocation parts.
On the item-item association task, patients performed significantly worse than their controls; again, this was due to worse overall performance, rather than on one specific measure, the team notes in the journal Psychiatry Research.
Unaffected parents also performed significantly worse overall than their controls on the item-item association task, which was due to significantly worse performance on the correct rejection of rearranged pairs, reflecting a recollection process. Parents also had difficulty distinguishing between old and rearranged pairs versus new pairs on the task.
"Given that the recollection deﬁcit is associated with schizophrenia and is more prevalent in unaffected family members than in the general population, this selective deﬁcit could be a candidate for genetic studies," the researchers conclude.
"The item-item association task allowed us to adequately distinguish patients and their unaffected parents from healthy controls."
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By Liam Davenport