TY - JOUR
T1 - Differential working memory impairment in bipolar disorder and schizophrenia
T2 - Effects of lifetime history of psychosis
AU - Glahn, David C.
AU - Bearden, Carrie E.
AU - Cakir, Sibel
AU - Barrett, Jennifer A.
AU - Najt, Pablo
AU - Serap Monkul, E.
AU - Maples, Natalie
AU - Velligan, Dawn I.
AU - Soares, Jair C.
PY - 2006/4
Y1 - 2006/4
N2 - Background: Although bipolar disorder and schizophrenia have long been viewed as distinct illnesses, there is growing evidence that these two complex diseases share some common genes, which may manifest as overlapping neuropsychological impairments. Although working memory dysfunction has been proposed to be central to the pathophysiology of schizophrenia, it has received less attention in studies of bipolar disorder. Method: We applied measures of working memory to patients with schizophrenia (n = 15), patients with schizoaffective disorder (n = 15), patients with psychotic (n = 11) and non-psychotic (n = 15) bipolar disorder, and demographically matched healthy subjects (n = 32), in order to determine the extent to which these groups show common or unique impairments. Results: While patients with bipolar disorder (with and without psychotic features) and those with schizophrenia/schizoaffective disorder were impaired on backward digit span, only patients with a lifetime history of psychotic features, regardless of diagnosis, were impaired on spatial delayed response task. Conclusions: Backward digit span performance is comparable in bipolar disorder and schizophrenia, and may be an appropriate endophenotypic marker that cuts across diagnostic categories. In contrast, spatial working memory performance clearly distinguishes non-psychotic bipolar disorder patients from patients with functional psychosis.
AB - Background: Although bipolar disorder and schizophrenia have long been viewed as distinct illnesses, there is growing evidence that these two complex diseases share some common genes, which may manifest as overlapping neuropsychological impairments. Although working memory dysfunction has been proposed to be central to the pathophysiology of schizophrenia, it has received less attention in studies of bipolar disorder. Method: We applied measures of working memory to patients with schizophrenia (n = 15), patients with schizoaffective disorder (n = 15), patients with psychotic (n = 11) and non-psychotic (n = 15) bipolar disorder, and demographically matched healthy subjects (n = 32), in order to determine the extent to which these groups show common or unique impairments. Results: While patients with bipolar disorder (with and without psychotic features) and those with schizophrenia/schizoaffective disorder were impaired on backward digit span, only patients with a lifetime history of psychotic features, regardless of diagnosis, were impaired on spatial delayed response task. Conclusions: Backward digit span performance is comparable in bipolar disorder and schizophrenia, and may be an appropriate endophenotypic marker that cuts across diagnostic categories. In contrast, spatial working memory performance clearly distinguishes non-psychotic bipolar disorder patients from patients with functional psychosis.
KW - Bipolar disorder
KW - Delayed response task
KW - Digit span
KW - Psychotic features
KW - Schizoaffective disorder
KW - Schizophrenia
KW - Working memory
UR - http://www.scopus.com/inward/record.url?scp=33745843694&partnerID=8YFLogxK
U2 - 10.1111/j.1399-5618.2006.00296.x
DO - 10.1111/j.1399-5618.2006.00296.x
M3 - Article
C2 - 16542181
AN - SCOPUS:33745843694
SN - 1398-5647
VL - 8
SP - 117
EP - 123
JO - Bipolar Disorders
JF - Bipolar Disorders
IS - 2
ER -