Review ARTICLE

Front. Hum. Neurosci., 01 September 2009 | doi: 10.3389/neuro.09.021.2009

Does abnormal sleep impair memory consolidation in schizophrenia?

1
Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA, USA
2
Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA
3
Harvard Medical School, Boston, MA, USA
4
Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
Although disturbed sleep is a prominent feature of schizophrenia, its relation to the pathophysiology, signs, and symptoms of schizophrenia remains poorly understood. Sleep disturbances are well known to impair cognition in healthy individuals. Yet, in spite of its ubiquity in schizophrenia, abnormal sleep has generally been overlooked as a potential contributor to cognitive deficits. Amelioration of cognitive deficits is a current priority of the schizophrenia research community, but most efforts to define, characterize, and quantify cognitive deficits focus on cross-sectional measures. While this approach provides a valid snapshot of function, there is now overwhelming evidence that critical aspects of learning and memory consolidation happen offline, both over time and with sleep. Initial memory encoding is followed by a prolonged period of consolidation, integration, and reorganization, that continues over days or even years. Much of this evolution of memories is mediated by sleep. This article briefly reviews (i) what is known about abnormal sleep in schizophrenia, (ii) sleep-dependent memory consolidation in healthy individuals, (iii) recent findings of impaired sleep-dependent memory consolidation in schizophrenia, and (iv) implications of impaired sleep-dependent memory consolidation in schizophrenia. This literature suggests that abnormal sleep in schizophrenia disrupts attention and impairs sleep-dependent memory consolidation and task automation. We conclude that these sleep-dependent impairments may contribute substantially to generalized cognitive deficits in schizophrenia. Understanding this contribution may open new avenues to ameliorating cognitive dysfunction and thereby improve outcome in schizophrenia.
Keywords:
sleep, schizophrenia, procedural learning, motor skill, memory consolidation, cognition, slow wave sleep, sleep spindles
Citation:
Manoach DS and Stickgold R (2009). Does abnormal sleep impair memory consolidation in schizophrenia? Front. Hum. Neurosci. 3:21. doi: 10.3389/neuro.09.021.2009
Received:
30 June 2009;
 Paper pending published:
06 August 2009;
Accepted:
12 August 2009;
 Published online:
01 September 2009.

Edited by:

Kenneth Hugdahl, University of Bergen, Norway

Reviewed by:

Janne Grønli, University of Bergen, Norway
Kenneth Hugdahl, University of Bergen, Norway
Copyright:
© 2009 Manoach and Stickgold. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited.
*Correspondence:
Dara S. Manoach, Psychiatric Neuroimaging, Massachusetts General Hospital, Charlestown Navy Yard, 149 13th Street, Room 2608, Charlestown, MA 02129, USA. e-mail: dara@nmr.mgh.harvard.edu
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