Psychopharmacology
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Administration of an opiate antagonist following acute morphine exposure elevates the startle response in rodents, a phenomenon that may reflect the anxiogenic effects of withdrawal. Previous acute dependence studies have demonstrated escalated withdrawal severity following multiple withdrawal episodes. ⋯ These data demonstrate that repeated withdrawals from acute morphine exacerbate the severity of potentiated startle and hyperalgesia. These paradigms may be useful in examining the neural plasticity underlying the development of opiate dependence.
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Although reports of caffeine withdrawal in the medical literature date back more than 170 years, the most rigorous experimental investigations of the phenomenon have been conducted only recently. ⋯ The caffeine-withdrawal syndrome has been well characterized and there is sufficient empirical evidence to warrant inclusion of caffeine withdrawal as a disorder in the DSM and revision of diagnostic criteria in the ICD.
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Clinical Trial
Occupancy of dopamine D2 receptors by the atypical antipsychotic drugs risperidone and olanzapine: theoretical implications.
To examine the D2 occupancy of two commonly used antipsychotic medications and relate this to the D2 occupancy by endogenous dopamine in schizophrenia. ⋯ These data indicate that the dosage of these medications, found to be effective in the treatment of schizophrenia, reduces DA stimulation of D2 receptors to levels slightly lower than those found in unmedicated healthy subjects.
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Comparative Study
Attentional biases for alcohol cues in heavy and light social drinkers: the roles of initial orienting and maintained attention.
There has been considerable theoretical interest in attentional biases for drug-related cues. However, there is little research on the component processes of such attentional biases. ⋯ These results suggest that biases in visual orienting to alcohol-related cues in heavy social drinkers operate mainly in the processes involved in the maintenance of attention.
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Quetiapine, an atypical neuroleptic, has beneficial antipsychotic effects in schizophrenic patients, but with a lower incidence of extrapyramidal symptoms (EPS) compared with typical antipsychotics. While typical antipsychotics are often switched to atypical agents when adverse effects become limiting, there is little preclinical information to support this strategy, both in terms of efficacy and side effects. ⋯ The present study demonstrated that the combined administration of quetiapine with haloperidol did not aggravate EPS, possibly because of its affinity for 5-HT1A receptors. This finding may have the clinical implication that quetiapine could provide a successful regimen in switching from typical antipsychotic agents in the symptom management of schizophrenia, or even in adjunctive therapy with other antipsychotic agents.