Alcohol use and mismatch negativity in young patients with psychotic disorder.
ABSTRACT Mismatch negativity (MMN) is a neurophysiological indicator of the brain's ability to extract relevant information from an irrelevant background. MMN has been described as a reliable biomarker of schizophrenia and more recently it has found to be impaired in the early stages of psychosis. In addition, drugs (including alcohol) that block glutamate's N-methyl-D-aspartate receptor have been shown to reduce MMN. This study aims to determine whether risky alcohol consumption in young patients with psychotic disorder further impacts or changes their MMN response. Patients with high-alcohol use were found to show reduced temporal MMN amplitudes compared with patients with low-alcohol use and controls. In contrast, early psychosis patients with low-alcohol use showed reduced fronto-central MMN amplitudes compared with controls; whereas patients with high-alcohol use showed an intermediate response at these sites. Correlational analysis revealed distinct patterns of association between MMN and alcohol use in patients with early psychosis compared with controls. This study shows that early psychosis outpatients who engaged in risky drinking have decreased temporal MMN amplitudes, compared with their peers. This may reflect an additive effect of N-methyl-D-aspartate receptor hypofunction and high-alcohol consumption.
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ABSTRACT: Impaired mismatch negativity (MMN) is a robust finding in schizophrenia and, more recently, similar impairments have been reported in other psychotic- and affective-disorders (including at early stages of illness). Although cross-sectional studies have been numerous, there are few longitudinal studies that have explored the predictive value of this event-related potential in relation to clinical/functional outcomes. This study assessed changes in MMN (and the concomitant P3a) amplitude over time and aimed to determine the longitudinal relationship between MMN/P3a and functional outcomes in patients recruited during the early stage of a schizophrenia- or affective-spectrum disorder.Progress in Neuro-Psychopharmacology and Biological Psychiatry 07/2013; 46:161-169. DOI:10.1016/j.pnpbp.2013.07.002 · 4.03 Impact Factor
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ABSTRACT: Cannabis use is prevalent among the early psychosis (EP) population. The event-related potentials, mismatch negativity (MMN) and P3a are reduced in EP. Cannabinoids have been shown to modulate N-methyl-D-aspartate receptors which are involved in MMN generation. This study is the first to investigate the effects of cannabis use on MMN/P3a in EP. EP was defined as a history of psychosis or psychotic symptoms with no progression to date to chronic schizophrenia. Twenty-two EP patients with cannabis use (EP + CANN), 22 non-cannabis-using EP patients (EP-CANN) and 21 healthy controls participated in this study. MMN/P3a was elicited using a two-tone, auditory paradigm with 8% duration deviants. As expected, EP-CANN showed marked reductions in MMN/P3a amplitudes compared to controls. However, EP + CANN showed evidence of a different pattern of neurophysiological expression of MMN/P3a compared to non-using patients, most notably in terms of delayed frontal MMN/P3a latencies. This study provides further evidence that MMN/P3a deficits are present during early psychosis and suggests that this biomarker may have utility in differentiating substance- from non-substance-related psychoses.Psychopharmacology 03/2012; 222(3):507-18. DOI:10.1007/s00213-012-2676-2 · 3.99 Impact Factor
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ABSTRACT: BACKGROUND: After 30 years of consensus-derived diagnostic categories in mental health, it is time to head in new directions. Those categories placed great emphasis on enhanced reliability and the capacity to identify them via standardized checklists. Although this enhanced epidemiology and health services planning, it failed to link broad diagnostic groupings to underlying pathophysiology or specific treatment response. DISCUSSION: It is time to adopt new goals that prioritize the validation of clinical entities and foster alternative strategies to support those goals. The value of new dimensions (notably clinical staging), that are both clinically relevant and directly related to emerging developmental and neurobiological research, is proposed. A strong emphasis on 'reverse translation' (that is, working back from the clinic to the laboratory) underpins these novel approaches. However, it relies on using diagnostic groupings that already have strong evidence of links to specific risk factors or patterns of treatment response. SUMMARY: The strategies described abandon the historical divides between clinical neurology, psychiatry and psychology and adopt the promotion of pathways to illness models.BMC Medicine 01/2013; 11(1):125. DOI:10.1186/1741-7015-11-125 · 7.28 Impact Factor