Biological psychiatry
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Biological psychiatry · May 2007
Altered central micro-opioid receptor binding after psychological trauma.
Functional neuroimaging studies have detected abnormal limbic and paralimbic activation to emotional probes in posttraumatic stress disorder (PTSD), but few studies have examined neurochemical mechanisms that underlie functional alterations in regional cerebral blood flow. The mu-opioid neurotransmitter system, implicated in responses to stress and suppression of pain, is distributed in and is thought to regulate the function of brain regions that are implicated in affective processing. ⋯ These findings differentiate the general response of the micro-opioid system to trauma from more specific changes associated with PTSD.
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Biological psychiatry · Feb 2007
The prevalence and correlates of eating disorders in the National Comorbidity Survey Replication.
Little population-based data exist on the prevalence or correlates of eating disorders. ⋯ Eating disorders, although relatively uncommon, represent a public health concern because they are frequently associated with other psychopathology and role impairment, and are frequently under-treated.
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Biological psychiatry · Jan 2007
Randomized Controlled Trial Comparative Study Clinical TrialCatechol-O-methyltransferase (COMT) gene variants predict response to bupropion therapy for tobacco dependence.
Although bupropion is efficacious for smoking cessation, only a minority of smokers are able to quit. Pharmacogenetic research may improve treatment outcomes through discovery of DNA sequences predictive of successful pharmacotherapy for subgroups of smokers. We investigated variants in the catechol-O-methyltransferase (COMT) gene in a smoking cessation trial of bupropion. ⋯ COMT haplotypes at rs737865 and rs165599 may predict a favorable outcome for bupropion treatment for smoking cessation. European-American smokers with a G allele at both SNPs may not benefit from bupropion treatment. Small numbers of some COMT haplotypes limit interpretation of response. If study findings are confirmed in additional large studies, COMT genotyping could be applied to identify likely responders to bupropion treatment for smoking cessation.
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Biological psychiatry · Dec 2006
Neonatal ventral hippocampal lesions potentiate amphetamine-induced increments in dopamine efflux in the core, but not the shell, of the nucleus accumbens.
In rats, neonatal ventral hippocampal lesions (NVHLs) result in the postpubertal emergence of alterations reminiscent of several features of schizophrenia, including increased responsivity to the behavioral effects of amphetamine (AMPH). The precise nature of presynaptic aspects of accumbal dopamine (DA) function in these alterations is however uncertain: previous studies have found that the exacerbated responses to AMPH of NVHL rats are associated with either decreased or unchanged DA efflux in the nucleus accumbens (NAc) as compared with shams. Because these studies investigated DA output in the whole NAc, it was considered of interest to examine the impact of NVHLs on DA transmission in NAc subregions involved in distinct aspects of goal-directed behavior. ⋯ The functional alterations in the NAc core induced by NVHLs provide a link between the hippocampal damage and striatal DA hyperactivity in schizophrenia.
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Biological psychiatry · Oct 2006
Context conditioning and behavioral avoidance in a virtual reality environment: effect of predictability.
Sustained anxiety can be modeled using context conditioning, which can be studied in a virtual reality environment. Unpredictable stressors increase context conditioning in animals. This study examined context conditioning to predictable and unpredictable shocks in humans using behavioral avoidance, potentiated startle, and subjective reports of anxiety. ⋯ Consistent with animal data, context conditioning is increased by unpredictability. These data support virtual reality as a tool to extend research on physiological and behavioral signs of fear and anxiety in humans.