An association study of monoamine oxidase A (MAOA) gene polymorphism in methamphetamine psychosis
ABSTRACT Methamphetamine continues to be the most widely abused drug in Japan. Chronic methamphetamine users show psychiatric signs, including methamphetamine psychosis. Monoamine oxidase A (MAOA) is one of the major enzymes responsible for the degradation of neurotransmitters. Abnormalities in MAO levels have been related to a wide range of psychiatric disorders. We examined whether or not the MAOA-u variable-number tandem repeat (VNTR) has a functional polymorphism in methamphetamine psychosis and whether or not such a polymorphism is related to the prolongation of psychosis. As expected, there was a significant difference in the MAOA-u VNTR between males with persistent versus transient methamphetamine psychosis (p=0.018, odds ratio (OR)=2.76, 95% CI: 1.18-6.46). Our results suggest that the high-activity allele class of MAOA-u VNTR in males may be involved in susceptibility to a persistent course of methamphetamine psychosis. We found no differences among females. The sample size of females with methamphetamine psychosis was too small to have significant analysis.
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ABSTRACT: Methamphetamine (meth) abuse is increasingly of public health concern and has been associated with neurocognitive dysfunction. Some previous studies have been hampered by background differences between meth users and comparison subjects, as well as unknown HIV and hepatitis C (HCV) status, which can also affect brain functioning. We compared the neurocognitive functioning of 54 meth dependent (METH+) study participants who had been abstinent for an average of 129 days, to that of 46 demographically comparable control subjects (METH-) with similar level of education and reading ability. All participants were free of HIV and HCV infection. The METH+ group exhibited higher rates of neuropsychological impairment in most areas tested. Among meth users, neuropsychologically normal (n=32) and impaired (n=22) subjects did not differ with respect to self-reported age at first use, total years of use, route of consumption, or length of abstinence. Those with motor impairment had significantly greater meth use in the past year, but impairment in cognitive domains was unrelated to meth exposure. The apparent lack of correspondence between substance use parameters and cognitive impairment suggests the need for further study of individual differences in vulnerability to the neurotoxic effects of methamphetamine.Drug and alcohol dependence 10/2009; 106(2-3):154-63. DOI:10.1016/j.drugalcdep.2009.08.010 · 3.42 Impact Factor
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ABSTRACT: Methamphetamine-associated psychosis (MAP) has been considered a pharmacological or environmental pathogen model of schizophrenia (SCZ) due in part to similarities in clinical presentation (i.e. paranoia, hallucinations, disorganized speech, and negative symptoms), response to treatment (e.g. neuroleptics), and pathologic mechanisms (e.g. central dopaminergic neurotransmission) of both conditions. In this chapter, we will provide an introduction to the typical clinical features and course of MAP as well as a review and discussion of the current putative genetic biomarkers for MAP. We will conclude with a discussion of the future directions and application of the MAP model with specific focus on how it may serve to elucidate further the complex neuromechanisms and discovery of viable biomarkers of SCZ. KeywordsMethamphetamine-Model of psychosis-Genetic-BiomarkersHandbook of Schizophrenia Spectrum Disorders, Volume I, 06/2011: pages 327-343;
Article: Methamphetamine-Associated Psychosis[Show abstract] [Hide abstract]
ABSTRACT: Methamphetamine (METH) is a frequent drug of abuse in U.S. populations and commonly associated with psychosis. This may be a factor in frequent criminal justice referrals and lengthy treatment required by METH users. Persecutory delusions and auditory hallucinations are the most consistent symptoms of METH-associated psychosis (MAP). MAP has largely been studied in Asian populations and risk factors have varied across studies. Duration, frequency and amount of use as well as sexual abuse, family history, other substance use, and co-occurring personality and mood disorders are risk factors for MAP. MAP may be unique with its long duration of psychosis and recurrence without relapse to METH. Seven candidate genes have been identified that may be associated with MAP. Six of these genes are also associated with susceptibility, symptoms, or treatment of schizophrenia and most are linked to glutamatergic neurotransmission. Animal studies of pre-pulse inhibition, attenuation of social interaction, and stereotypy and alterations in locomotion are used to study MAP in rodents. Employing various models, rodent studies have identified neuroanatomical and neurochemical changes associated with METH use. Throughout this review, we identify key gaps in our understanding of MAP and suggest potential directions for future research.Journal of Neuroimmune Pharmacology 07/2011; 7(1):113-39. DOI:10.1007/s11481-011-9288-1 · 4.11 Impact Factor