Diagnosis-specific effect of familial loading on verbal working memory in schizophrenia.
BACKGROUND
Working memory disturbances are a frequently replicated finding in schizophrenia and less consistent also in schizoaffective disorder. Working memory dysfunctions have been shown to be heritable and have been proposed to represent a promising endophenotype of schizophrenic psychoses.


METHODS
In the present study, we investigated the effects of familial loading on performance rates in circuit-specific verbal and visuospatial working memory tasks in matched samples of schizophrenic patients (from multiply affected or uniaffected families), schizoaffective patients (from multiply affected or uniaffected families), and healthy subjects.


RESULTS
We found a significant interaction effect between familial loading and diagnosis in terms of a diagnosis-specific detrimental effect of familial loading on the performance of schizophrenic (but not schizoaffective) patients in the articulatory rehearsal task.


CONCLUSIONS
This finding of a circuit-specific verbal working memory deficit in schizophrenic patients with additional familial loading is consistent with prior studies, which provided evidence for the existence of specific subgroups of schizophrenic patients with selective working memory impairments and for diagnosis-specific dysfunctions of the articulatory rehearsal mechanism in schizophrenic, but not in schizoaffective patients. Together, these findings suggest that the genetic risk for (a subtype of) schizophrenia may be associated with dysfunctions of the brain system, which underlies the articulatory rehearsal mechanism, the probably phylogenetically youngest part of human working memory.
Zilles
David
D
Department of Psychiatry and Psychotherapy, Georg August University, 37075 Göttingen, Germany.
Burke
Sarah
S
Schneider-Axmann
Thomas
T
Falkai
Peter
P
Gruber
Oliver
O
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D005192:Family Health; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology / Q000235:genetics; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000150:complications; D012559:Schizophrenia / Q000150:complications* / Q000235:genetics*; D013028:Space Perception / Q000502:physiology; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult