Psychopharmacology
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Randomized Controlled Trial Comparative Study
The effects of intranasal esketamine (84 mg) and oral mirtazapine (30 mg) on on-road driving performance: a double-blind, placebo-controlled study.
The purpose of this study is to evaluate the single dose effect of intranasal esketamine (84 mg) compared to placebo on on-road driving performance. Mirtazapine (oral, 30 mg) was used as a positive control, as this antidepressant drug is known to negatively affect driving performance. ⋯ No significant difference in driving performance was observed 8 h after administering intranasal esketamine (84 mg) or placebo. In contrast, oral mirtazapine (30 mg) significantly impaired on road driving performance.
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Randomized Controlled Trial
Acute and chronic effects of cannabinoids on effort-related decision-making and reward learning: an evaluation of the cannabis 'amotivational' hypotheses.
Anecdotally, both acute and chronic cannabis use have been associated with apathy, amotivation, and other reward processing deficits. To date, empirical support for these effects is limited, and no previous studies have assessed both acute effects of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), as well as associations with cannabis dependence. ⋯ Cannabis acutely induced a transient amotivational state and CBD influenced the effects of THC on expected value. In contrast, cannabis dependence was associated with preserved motivation alongside impaired reward learning, although confounding factors, including depression, cannot be disregarded. This is the first well powered, fully controlled study to objectively demonstrate the acute amotivational effects of THC.
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Randomized Controlled Trial
On-the-road driving performance after use of the antihistamines mequitazine and l-mequitazine, alone and with alcohol.
Previous studies demonstrated that mequitazine produces mild sedation after single doses. Its enantiomer, l-mequitazine, has a stronger potency for the H1 receptor. The aim of the current study was to assess the effects of l-mequitazine and mequitazine, alone and with alcohol, on driving. ⋯ L-mequitazine can be considered safe to drive in dosages of 2.5 and 5.0 mg. L-mequitazine 10 mg led to mild driving impairment. Alcohol impaired all performance measures and added to the effects of l-mequitazine and mequitazine.
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Randomized Controlled Trial
Levodopa impairs probabilistic reversal learning in healthy young adults.
Dopaminergic therapy improves some cognitive functions and worsens others in patients with Parkinson's disease (PD). These paradoxical effects are explained by the dopamine overdose hypothesis, which proposes that effects of dopaminergic therapy on a cognitive function is determined by the baseline dopamine levels in brain regions mediating that function. ⋯ Exogenous dopamine impairs stimulus-reward learning, independent of PD pathology and prior to sensitization through repeated exposure, in healthy adults with normal cognition and baseline dopamine function. Our findings support the dopamine overdose hypothesis and caution clinicians about detrimental effects of levodopa in all clinical populations (e.g., early PD, restless leg syndrome) regardless of baseline cognitive and dopaminergic system function.
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Randomized Controlled Trial Multicenter Study
Efficacy and safety of quetiapine extended release monotherapy in bipolar depression: a multi-center, randomized, double-blind, placebo-controlled trial.
Quetiapine extended release (XR) has been used to treat various psychiatric disorders, including depressive episodes associated with bipolar I and II disorders. Quetiapine XR is the first approved drug in China for the treatment of bipolar disorder. ⋯ This study, which is the first to evaluate 300 mg/day quetiapine XR monotherapy for depression in Chinese patients with bipolar disorders, found that this drug was superior to the placebo. Quetiapine XR was generally safe and well tolerated (ClinicalTrials.gov number, NCT01256177).