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SHORT REPORTS |
Sheffield Cognition and Neuroimaging Laboratory (SCANLab), Academic Clinical Psychiatry, University of Sheffield, UK
Correspondence: Dr Tom F. D. Farrow, SCANLab, Academic Clinical Psychiatry, University of Sheffield, The Longley Centre, Northern General Hospital, Norwood Grange Drive, Sheffield S5 7JT, UK. Email: t.f.farrow{at}sheffield.ac.uk
Declaration of interest This study was funded by a grant awarded to S.A.S. by Cephalon UK, the manufacturers of modafinil. The sponsor was involved in the study design, but had no role in data collection, analysis, the writing of the reportor the decision to submit the paper for publication.
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ABSTRACT |
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INTRODUCTION |
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In this study we recorded the spontaneous, unconstrained motor behaviour of people with schizophrenia in order to determine whether such behaviour might be influenced by modafinil, a novel wakefulness-promoting agent currently licensed in the USA and the UK for the treatment of narcolepsy (Cephalon, 1999). Congruent with its wakefulness-promoting properties, in animal models modafinil increases activity in the anterior hypothalamus and anterior cingulate structures implicated in arousal (Lin et al, 1996). Of particular relevance to modafinils application in schizophrenia is its activity with respect to the human dopaminergic system. Animal models have differentiated modafinils pharmacological properties from those of amphetamines (Lin et al, 1996), and there is evidence that its wakefulness-promoting effects are not antagonised by haloperidol (Mignot et al, 1994). In humans, peak modafinil plasma levels occur 24 h following oral dosing (Cephalon, 1999). As well as its use in the treatment of narcolepsy, modafinil has been investigated in a range of psychiatric disorders that have fatigue or anergia as a central feature, such as depression (DeBattista et al, 2004). There have been preliminary reports of its general use in schizophrenia to ameliorate negative symptoms (e.g. Rosenthal & Bryant, 2003; given at a dosage of 100200 mg per day).
In order to investigate whether the lower dosage of modafinil might be of use in the remediation of avolition in schizophrenia we conducted a trial of its acute effects, including an objective measure of volume of movement.
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METHOD |
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Patients wore an Actiwatch (Cambridge Neurotechnology Ltd, Cambridge, UK) to measure their cumulative activity over a 20 h period. The Actiwatch is a wrist-worn device containing a miniature uniaxial accelerometer, which produces a digital integration of the amount and duration of all movement over 0.05 g (equivalent to an acceleration of approximately 0.5 m/s2). As an indicator of normal daytime activity, a study of 107 young people aged 1619 years recorded mean Actiwatch readings of 162 565 (s.d.=68 620), a dimensionless measure, over a 24 h period (Nancy Butte, personal communication, 2005). All participants gave written informed consent, and the study was approved by the North Sheffield Research Ethics Committee.
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RESULTS |
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DISCUSSION |
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Using the Actiwatch to augment ratings obtained using the SANS facilitates a more objective, scalar measure of bodily movement and severity of avolition. This additional quantification is simple to acquire, unobtrusive to patients and may be particularly useful where change is anticipated (as with putative behavioural or pharmacological interventions).
Our study findings are potentially limited, however, in two respects. First, we studied patients within the confines of a psychiatric ward and therefore must remain circumspect in drawing inferences about ambulatory, community-based activity. Second, although we have a sum of the total activity undertaken by our participants, we are limited in the extent to which we may infer purpose (i.e. goal direction) in such activity. Nevertheless, our data suggest that administration of modafinil is associated with an increase in unconstrained motor activity in chronic schizophrenia and this may have implications for future strategies aimed at increasing volitional behaviour in those affected by negative symptoms. In the light of recent reports of modafinils cognitive-enhancing effects in chronic schizophrenia (Turner et al, 2004), and with further understanding of the brain systems through which it acts (Spence et al, 2005; Hunter et al, 2006), the clinical potential for its use remains promising, although further work is required.
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ACKNOWLEDGMENTS |
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REFERENCES |
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Received for publication September 20, 2005. Revision received February 10, 2006. Accepted for publication April 3, 2006.
This article has been cited by other articles:
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S. Morein-Zamir, D. C. Turner, and B. J. Sahakian A Review of the Effects of Modafinil on Cognition in Schizophrenia Schizophr Bull, November 1, 2007; 33(6): 1298 - 1306. [Abstract] [Full Text] [PDF] |
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