TY - JOUR
T1 - Dissociable mechanisms for memory impairment in bipolar disorder and schizophrenia
AU - Glahn, David C.
AU - Barrett, Jennifer
AU - Bearden, Carrie E.
AU - Mintz, Jim
AU - Green, Michael F.
AU - Serap Monkul, E.
AU - Najt, Pablo
AU - Soares, Jair C.
AU - Velligan, Dawn I.
PY - 2006/8
Y1 - 2006/8
N2 - Background. Although memory deficits are consistently reported in schizophrenia and bipolar disorder, the mechanisms underlying these impairments are poorly understood. Clarifying the nature and degree of overlap in memory deficits between the two illnesses could help to distinguish brain systems disrupted in these illnesses, and indicate cognitive remediation strategies to improve patient outcomes. Method. We examined performance on a non-verbal memory task in clinically stable out-patients with bipolar disorder (n=40), schizophrenia (n=40), and healthy comparison subjects (n=40). This task includes conditions in which distinct mnemonic strategies - namely, using context to organize familiar stimuli or using holistic representation of novel stimuli - facilitate performance. Result. When compared to a reference condition, bipolar patients had deficits consistent with organizational dysfunction and poor detection of novel information. Although patients with schizophrenia performed worse than the other groups, they were only differentially impaired when organizational demands were significant. Task performance was not correlated with severity of clinical symptomatology. Conclusions. This pattern of distinct memory impairments implies disturbances in partially overlapping neural systems in bipolar disorder and schizophrenia. Evidence of impairment in detection of novel stimuli that is unique to bipolar disorder suggests that, while the absolute level of cognitive dysfunction is less severe in bipolar disorder as compared to schizophrenia, subtle disruptions in memory are present. These findings can be used to plan targeted cognitive remediation programs by helping patients to capitalize on intact functions and to learn new strategies that they do not employ without training.
AB - Background. Although memory deficits are consistently reported in schizophrenia and bipolar disorder, the mechanisms underlying these impairments are poorly understood. Clarifying the nature and degree of overlap in memory deficits between the two illnesses could help to distinguish brain systems disrupted in these illnesses, and indicate cognitive remediation strategies to improve patient outcomes. Method. We examined performance on a non-verbal memory task in clinically stable out-patients with bipolar disorder (n=40), schizophrenia (n=40), and healthy comparison subjects (n=40). This task includes conditions in which distinct mnemonic strategies - namely, using context to organize familiar stimuli or using holistic representation of novel stimuli - facilitate performance. Result. When compared to a reference condition, bipolar patients had deficits consistent with organizational dysfunction and poor detection of novel information. Although patients with schizophrenia performed worse than the other groups, they were only differentially impaired when organizational demands were significant. Task performance was not correlated with severity of clinical symptomatology. Conclusions. This pattern of distinct memory impairments implies disturbances in partially overlapping neural systems in bipolar disorder and schizophrenia. Evidence of impairment in detection of novel stimuli that is unique to bipolar disorder suggests that, while the absolute level of cognitive dysfunction is less severe in bipolar disorder as compared to schizophrenia, subtle disruptions in memory are present. These findings can be used to plan targeted cognitive remediation programs by helping patients to capitalize on intact functions and to learn new strategies that they do not employ without training.
UR - http://www.scopus.com/inward/record.url?scp=33746144043&partnerID=8YFLogxK
U2 - 10.1017/S0033291706007902
DO - 10.1017/S0033291706007902
M3 - Article
C2 - 16734948
AN - SCOPUS:33746144043
SN - 0033-2917
VL - 36
SP - 1085
EP - 1095
JO - Psychological Medicine
JF - Psychological Medicine
IS - 8
ER -