Journal of psychopharmacology
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J. Psychopharmacol. (Oxford) · Oct 2012
Δ⁹Tetrahydrocannabinol impairs visuo-spatial associative learning and spatial working memory in rhesus macaques.
Cannabis remains the most commonly abused illicit drug and is rapidly expanding in quasi-licit use in some jurisdictions under medical marijuana laws. Effects of the psychoactive constituent Δ⁹tetrahydrocannabinol (Δ⁹THC) on cognitive function remain of pressing concern. Prior studies in monkeys have not shown consistent evidence of memory-specific effects of Δ⁹THC on recognition tasks, and it remains unclear to what extent Δ⁹THC causes sedative versus specific cognitive effects. ⋯ It is concluded that Δ⁹THC disrupts cognition in a way that is consistent with a direct effect on memory. There was evidence for interference with spatial working memory, visuo-spatial associative memory and incremental learning in the latter task. These results and the lack of specific effect of Δ⁹THC in prior visual recognition studies imply a sensitivity of spatial memory processing and/or working memory to endocannabinoid perturbation.
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J. Psychopharmacol. (Oxford) · Aug 2012
Involvement of the cholinergic system of CA1 on harmane-induced amnesia in the step-down passive avoidance test.
β-carboline alkaloids such as harmane (HA) are naturally present in the human food chain. They are derived from the plant Peganum harmala and have many cognitive effects. In the present study, effects of the nicotinic system of the dorsal hippocampus (CA1) on HA-induced amnesia and exploratory behaviors were examined. ⋯ On the other hand, pre-test intra-CA1 injection of ineffective doses of nicotine (0.1 and 0.25 µg/mouse) fully reversed HA-induced impairment of memory after pre-training injection of HA (15 mg/kg, i.p.) which did not alter exploratory behaviors. Furthermore, pre-testing administration of mecamylamine (0.5, 1 and 2 µg/mouse, intra-CA1) did not alter memory retrieval but fully reversed HA-induced impairment of memory after pre-training injection of HA (15 mg/kg, i.p.) which had no effect on exploratory behaviors. In conclusion, the present findings suggest the involvement of the nicotinic cholinergic system in the HA-induced impairment of memory formation.
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J. Psychopharmacol. (Oxford) · Jun 2012
ReviewSystematic review of national and international guidelines on attention-deficit hyperactivity disorder.
During the last few years several clinical guidelines on attention-deficit hyperactivity disorder (ADHD) have been published by national and international medical societies. To systematically review and compare recommendations of selected ADHD guidelines, we performed a systematic search in online guideline databases and PubMed in order to retrieve guideline texts. Guidelines meeting inclusion criteria were reviewed and recommendations on assessment and treatment extracted. ⋯ They reflect similarities and differences of healthcare systems. Diagnosis throughout the lifespan is based on a detailed clinical history. There is greater agreement on evidence-based pharmacological treatment than on psychosocial interventions, reflecting the strength of evidence.
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J. Psychopharmacol. (Oxford) · Apr 2012
Randomized Controlled TrialSwitching from long-term benzodiazepine therapy to pregabalin in patients with generalized anxiety disorder: a double-blind, placebo-controlled trial.
To evaluate the efficacy of pregabalin in facilitating taper off chronic benzodiazepines, outpatients (N = 106) with a lifetime diagnosis of generalized anxiety disorder (current diagnosis could be subthreshold) who had been treated with a benzodiazepine for 8-52 weeks were stabilized for 2-4 weeks on alprazolam in the range of 1-4 mg/day. Patients were then randomized to 12 weeks of double-blind treatment with either pregabalin 300-600 mg/day or placebo while undergoing a gradual benzodiazepine taper at a rate of 25% per week, followed by a 6-week benzodiazepine-free phase during which they continued double-blind study treatment. Outcome measures included ability to remain benzodiazepine-free (primary) as well as changes in Hamilton Anxiety Rating Scale (HAM)-A and Physician Withdrawal Checklist (PWC). ⋯ Treatment with pregabalin was associated with significantly greater endpoint reduction in the HAM-A total score versus placebo (-2.5 vs +1.3; p < 0.001), and lower endpoint mean PWC scores (6.5 vs 10.3; p = 0.012). Thirty patients (53%) in the pregabalin group and 19 patients (37%) in the placebo group completed the study, reducing the power to detect a significant difference on the primary outcome. The results on the anxiety and withdrawal severity measures suggest that switching to pregabalin may be a safe and effective method for discontinuing long-term benzodiazepine therapy.
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J. Psychopharmacol. (Oxford) · Apr 2012
D1 and D2 dopaminergic systems in the rat basolateral amygdala are involved in anxiogenic-like effects induced by histamine.
Involvement of the dopamine receptors in the basolateral amygdala (BLA) in the effects of histamine on anxiety-like behaviors of the elevated plus maze in male Wistar rats was investigated. The results showed that bilateral intra-BLA injections of histamine (2.5, 5 and 7.5 µg/rat) induced an anxiogenic-like effect, revealed by decreases in percentage of open arm time (%OAT) and open arm entries (%OAE). Intra-BLA administration of dopamine D1 receptor agonist, SKF38393 (0.25 µg/rat), and dopamine D2 receptor agonist, quinpirole (0.03 and 0.05 µg/rat), decreased %OAT but not %OAE. ⋯ On the other hand, intra-BLA pretreatment with a silent dose of SCH23390 (0.25 µg/rat) or sulpiride (0.1 µg/rat) prevented the anxiogenic-like effect of higher doses of histamine (5 and 7.5 µg/rat). No significant change was observed in total closed arm entries, as an index for motor activity of the animals. It can be concluded that the dopamine D1 and D2 receptors in the BLA may be involved in the anxiogenic-like effects induced by histamine.