Abstract
BackgroundCognitive deficits are considered core symptoms of the schizophrenia. Cognitive function has been found to be a better predictor of functional outcome than symptom levels. Changed mismatch negativity (MMN) reflects abnormalities of early auditory processing in schizophrenia. Up to now, no studies for the effects of aripiprazole on MMN in schizophrenia have been reported.Methodology/Principal FindingsSubjects included 26 patients with schizophrenia, and 26 controls. Psychopathology was rated in patients with the Positive and Negative Syndrome Scale (PANSS) at baseline, after 4- and 8-week treatments with aripiprazole. Auditory stimuli for ERP consisted of 100 millisecond/1000 Hz standards, intermixed with 100 millisecond/1500 Hz frequency deviants and 250 millisecond/1000 Hz duration deviants. EEG was recorded at Fz. BESA 5.1.8 was used to perform data analysis. MMN waveforms were obtained by subtracting waveforms elicited by standards from waveforms elicited by frequency- or duration-deviant stimuli. Aripiprazole decreased all PANSS. Patients showed smaller mean amplitudes of frequency and duration MMN at baseline than did controls. A repeated measure ANOVA with sessions (i.e., baseline, 4- and 8-week treatments) and MMN type (frequency vs. duration) as within-subject factors revealed no significant MMN type or MMN type × session main effect for MMN amplitudes. Session main effect was significant. LSD tests demonstrated significant differences between MMN amplitudes at 8 weeks and those at both baseline and 4 weeks. There was significant negative correlation between changes in amplitudes of frequency and duration MMN and changes in PANSS total scores at baseline and follow-up periods.ConclusionsAripiprazole improved the amplitudes of MMN. MMN offers objective evidence that treatment with the aripiprazole may ameliorate preattentive deficits in schizophrenia.
Highlights
Cognitive deficits in many domains have been consistently replicated in patients with schizophrenia
Strong dopamine D2 blockade and activity at the serotonin receptors as well as at postsynaptic D2 receptors might be responsible for its efficacy in reducing positive and somewhat negative symptoms, respectively; D2-receptor occupancy may be negatively correlated with certain types of learning, and aripiprazole’ s partial-agonist activity may have implications for its effect on learning compared with typical antipsychotics [7]
There was significant negative correlation between changes in amplitudes of frequency and duration MMN and changes in Positive and Negative Syndrome Scale (PANSS) total scores at baseline and follow-up periods(r = 20.39, 20.42, P = 0.012, 0.016 respectively).There was no significant correlation between changes in latencies of frequency and duration MMN and changes in PANSS total scores at baseline and follow-up periods. (Table 2)
Summary
Cognitive deficits in many domains have been consistently replicated in patients with schizophrenia. These domains include the executive functions, perceptual and motor processing, attentional skills, vigilance, verbal learning and memory, spatial working memory, and verbal fluency [1,2]. These deficits are considered core symptoms of the schizophrenia. Most studies that link cognitive deficits to functional outcome in schizophrenia support the notion that neurocognitive function predicts social and occupational function. Aripiprazole is a dopamine partial agonist approved for use in adults for short- and long-term treatment of schizophrenia and bipolar disorder. No studies for the effects of aripiprazole on MMN in schizophrenia have been reported
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