Biological psychiatry
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Biological psychiatry · Aug 2007
Hippocampal volume and mood disorders after traumatic brain injury.
Recent evidence from clinical studies and animal models of traumatic brain injury (TBI) suggest that neuronal and glial loss might progress after the initial insult in selectively vulnerable regions of the brain such as the hippocampus. There is also evidence that hippocampal dysfunction plays a role in the pathogenesis of mood disorders. We examined the relationship between hippocampal damage and mood disorders after TBI and the effect of hippocampal atrophy on the outcome of TBI patients. ⋯ Our findings are consistent with a "double-hit" mechanism by which neural and glial elements already affected by trauma are further compromised by the functional changes associated with mood disorders (e.g., the neurotoxic effects of increased levels of cortisol or excitotoxic damage resulting from overactivation of glutaminergic pathways). Finally, patients with greater hippocampal damage were less likely to return to a productive life 1 year after trauma.
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Biological psychiatry · Aug 2007
Risperidone exerts potent anti-aggressive effects in a developmentally immature animal model of escalated aggression.
Risperidone has been shown to be clinically effective for the treatment of aggressive behavior in children, yet no information is available regarding whether risperidone exhibits aggression-specific suppression in preclinical studies that use validated developmentally immature animal models of escalated aggression. Previously, we have shown that exposure to low doses of the psychostimulant cocaine-hydrochloride (.5 mg/kg intraperitoneally) during the majority of pubertal development (postnatal days [P]27-57) generates animals that exhibit a high level of offensive aggression. This study examined whether risperidone exerts selective aggression-suppressing effects by using this pharmacologic animal model of highly escalated offensive aggression. ⋯ These studies provide evidence that risperidone exerts specific aggression-suppressing effects in a developmentally immature animal model of escalated aggression.