Impaired working memory (WM) functioning is a common finding in schizophrenic patients.
Healthy relatives of affected patients also show WM deficits when compared to control
subjects without family history of schizophrenia. Thus, a strong genetic influence
can be assumed, and WM functioning is considered as an endophenotype of the disease.
In the present study, we investigated the effect of genetic loading on WM performance
in schizophrenic patients. Patients were divided into two groups, one group consisting
of patients with at least one more affected family member, and the other group without
any affected relatives. Both patients and healthy control subjects performed a battery
of 4 different WM-tasks and were compared with regard to their performance. Results: In the verbal WM-task which was performed by using verbal rehearsal, patients with
family history of schizophrenia performed significantly worse compared to both control
subjects and patients without family history. Similar results were found for another
verbal and two visuo-spatial WM-tasks, though the differences between the patient
groups did not reach the level of significance. Discussion: In spite of the low sample size (n=8 in each group) we found a significant influence
of familial loading on working memory performance in schizophrenic patients. Especially
the verbal rehearsal mechanism seems to be under strong genetic influence as it differentiates
between patients with and without family history.
