Archives of general psychiatry
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Arch. Gen. Psychiatry · Feb 2008
Randomized Controlled TrialGlutamate and the neural basis of the subjective effects of ketamine: a pharmaco-magnetic resonance imaging study.
Ketamine evokes psychosislike symptoms, and its primary action is to impair N-methyl-D-aspartate glutamate receptor neurotransmission, but it also induces secondary increases in glutamate release. ⋯ These 2 changes may underpin 2 fundamental processes of psychosis: abnormal perceptual experiences and impaired cognitive-emotional evaluation of their significance. The results are compatible with the theory that the neural and subjective effects of ketamine involve increased glutamate release.
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Arch. Gen. Psychiatry · Feb 2008
Controlled Clinical TrialPlacebo and nocebo effects are defined by opposite opioid and dopaminergic responses.
Placebo and nocebo effects, the therapeutic and adverse effects, respectively, of inert substances or sham procedures, represent serious confounds in the evaluation of therapeutic interventions. They are also an example of cognitive processes, particularly expectations, capable of influencing physiology. ⋯ Placebo and nocebo effects are associated with opposite responses of DA and endogenous opioid neurotransmission in a distributed network of regions. The brain areas involved in these phenomena form part of the circuit typically implicated in reward responses and motivated behavior.