Biological psychiatry
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Biological psychiatry · May 2009
Comparative StudyAmino acid neurotransmitters assessed by proton magnetic resonance spectroscopy: relationship to treatment resistance in major depressive disorder.
Significant alterations in gamma-aminobutyric acid (GABA) and glutamate levels have been previously reported in major depressive disorder (MDD); however, no studies to date have investigated associations between these amino acid neurotransmitters and treatment resistance. ⋯ Our findings corroborate previous reports of decreased GABA in MDD and provide initial evidence for a distinct neuronal amino acid profile in patients who have failed to respond to several standard antidepressants, possibly indicative of abnormal glutamate/glutamine/GABA cycling. Given interest in novel antidepressant mechanisms in TRD that selectively target amino acid neurotransmitter function, the translational relevance of these findings awaits further study.
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Biological psychiatry · Jan 2009
Randomized Controlled Trial Comparative StudyFamily history of alcohol dependence and initial antidepressant response to an N-methyl-D-aspartate antagonist.
A high rate of comorbidity exists between mood disorders and alcohol dependence. Furthermore, both ketamine, a dissociative anesthetic with a recently described rapid-onset antidepressant effect, and ethanol are N-methyl-D-aspartate (NMDA) receptor antagonists. Previous investigations of healthy individuals with a family history of alcohol dependence have found that these individuals have an attenuated response to ketamine's perceptual disturbance and dysphoric effects similar to that found in individuals with a self-reported history of alcohol dependence. This study investigated whether a family history of alcohol dependence influences ketamine's initial antidepressant effect. ⋯ A family history of alcohol dependence appears to predict a rapid initial antidepressant response to an NMDA receptor antagonist.
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Biological psychiatry · Jan 2009
Absence of embodied empathy during pain observation in Asperger syndrome.
Asperger syndrome (AS) is a neurodevelopmental condition within the autism spectrum conditions (ASC) characterized by specific difficulties in communication, social interaction, and empathy that is essential for sharing and understanding others' feelings and emotions. Although reduced empathy is considered a core feature of ASC, neurophysiological evidence of empathic deficits before and below mentalizing and perspective taking is lacking. We explored whether people with AS differ from neurotypical control participants in their empathic corticospinal response to the observation of others' pain and the modulatory role played by phenomenal experience of observed pain and personality traits. ⋯ Finding no embodiment of others' pain provides neurophysiological evidence for reduced empathic resonance in people with AS and indicates that their empathic difficulties involve not only cognitive dimensions but also sensorimotor resonance with others. We suggest that absence of embodied empathy may be linked to changes at very basic levels of neural processing.