TY - JOUR
T1 - Β-Amyloid Burden is Not Associated with Cognitive Impairment in Schizophrenia
T2 - A Systematic Review
AU - Chung, Jun Ku
AU - Nakajima, Shinichiro
AU - Plitman, Eric
AU - Iwata, Yusuke
AU - Uy, Danielle
AU - Gerretsen, Philip
AU - Caravaggio, Fernando
AU - Chakravarty, M. Mallar
AU - Graff-Guerrero, Ariel
N1 - Funding Information:
Mr. Chung received a Frederick Banting and Charles Best Canada Graduate Scholarships Master's Award (the Canadian Institutes of Health Research [CIHR]). Dr. Nakajima has received fellowship grants from the CIHR , the Japan Society for the Promotion of Science (grant 12J00172 ), and the Nakatomi Foundation and manuscript fees from Dainippon Sumitomo Pharma and Kyowa Hakko Kirin . Dr. Iwata has received manuscript fees from Dainippon Sumitomo Pharma and Wiley Japan within the past 3 years. Mr. Plitman received a Master's Award: Frederick Banting and Charles Best Canada Graduate Scholarships (CIHR) and an Ontario Gradudate Scholarship. Dr. Graff-Guerrero has received CIHR grant MOP-97946 and U.S. National Institutes of Health grant RO1MH084886 . These grant agencies did not influence study design, data acquisition and analysis, or journal selection for submission. All other authors report no disclosures.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - Current literature suggests that the pathology of schizophrenia (SCZ) has developmental origins. However, the neurodevelopmental theory of SCZ cannot solely explain progressive neurodegenerative processes in the illness. There is evidence of accelerated cognitive decline and increased risk of dementia in elderly patients with SCZ. Investigating β-amyloid (Aβ), we conducted a systematic review focusing on Aβ in patients with SCZ. An OVID literature search using PsychINFO, Medline, and Embase databases was conducted, looking for studies that compared Aβ levels between patients with SCZ and either elderly control subjects, patients with Alzheimer disease (AD), or patients with other psychiatric illnesses. Among 14 identified studies, 11 compared Aβ between SCZ and elderly control subjects, 7 between SCZ and AD, and 3 between SCZ and other psychiatric illnesses. As a result, no evidence was found suggesting that Aβ levels differ in patients with SCZ from elderly control subjects or patients with other psychiatric illnesses. All seven studies reported lower cortical Aβ in patients with SCZ than patients with AD. Furthermore, three of the four studies, which investigated the relationship between Aβ and cognitive impairment in SCZ, observed no association between two factors. The limitations of the included studies are small sample sizes, the inclusion of cerebrospinal fluid Aβ or postmortem plaques rather than cortical Aβ assessment in vivo, and the investigation of different brain regions. In conclusion, Aβ deposition is not associated with cognitive decline in late-life SCZ. Future studies should investigate other neurodegenerative indicators in SCZ to better understand the pathophysiologic mechanisms underlying this illness.
AB - Current literature suggests that the pathology of schizophrenia (SCZ) has developmental origins. However, the neurodevelopmental theory of SCZ cannot solely explain progressive neurodegenerative processes in the illness. There is evidence of accelerated cognitive decline and increased risk of dementia in elderly patients with SCZ. Investigating β-amyloid (Aβ), we conducted a systematic review focusing on Aβ in patients with SCZ. An OVID literature search using PsychINFO, Medline, and Embase databases was conducted, looking for studies that compared Aβ levels between patients with SCZ and either elderly control subjects, patients with Alzheimer disease (AD), or patients with other psychiatric illnesses. Among 14 identified studies, 11 compared Aβ between SCZ and elderly control subjects, 7 between SCZ and AD, and 3 between SCZ and other psychiatric illnesses. As a result, no evidence was found suggesting that Aβ levels differ in patients with SCZ from elderly control subjects or patients with other psychiatric illnesses. All seven studies reported lower cortical Aβ in patients with SCZ than patients with AD. Furthermore, three of the four studies, which investigated the relationship between Aβ and cognitive impairment in SCZ, observed no association between two factors. The limitations of the included studies are small sample sizes, the inclusion of cerebrospinal fluid Aβ or postmortem plaques rather than cortical Aβ assessment in vivo, and the investigation of different brain regions. In conclusion, Aβ deposition is not associated with cognitive decline in late-life SCZ. Future studies should investigate other neurodegenerative indicators in SCZ to better understand the pathophysiologic mechanisms underlying this illness.
KW - Alzheimer disease
KW - cognitive decline
KW - neurodegeneration
KW - schizophrenia
KW - β-Amyloid
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U2 - 10.1016/j.jagp.2016.03.013
DO - 10.1016/j.jagp.2016.03.013
M3 - Review article
C2 - 27526990
AN - SCOPUS:84994908881
VL - 24
SP - 923
EP - 939
JO - American Journal of Geriatric Psychiatry
JF - American Journal of Geriatric Psychiatry
SN - 1064-7481
IS - 10
ER -