European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology
-
Eur Neuropsychopharmacol · Aug 2008
Randomized Controlled Trial Controlled Clinical TrialEffects of acute oral Delta9-tetrahydrocannabinol and standardized cannabis extract on the auditory P300 event-related potential in healthy volunteers.
Reduced amplitudes of auditory evoked P300 are a robust finding in schizophrenic patients, indicating deficient attentional resource allocation and active working memory. Delta9-Tetrahydrocannabinol (Delta9-THC), the main active constituent of Cannabis sativa, has been known to acutely impair cognitive abilities in several domains, particularly in memory and attention. Given the psychotic-like effects of Delta9-THC, a cannabinoid hypothesis of schizophrenia has been proposed. ⋯ Moreover, there were no correlations between cannabinoid plasma concentrations and P300 parameters. These data suggest that Delta(9)-THC may lead to acute impairment of attentional functioning and working memory. It can be speculated whether the lack of effect of CBD may be due to an insufficient dose used or to an involvement of neurotransmitter systems in P300 generation which are not influenced by CBD.
-
An emerging literature has started to document the neuronal changes associated with the placebo phenomenon. This has altered placebo from being considered a nuisance factor in clinical research to a target of scientific investigation per se. This paper reviews the neuroimaging literature on the placebo effect, and illustrates how imaging tools can improve current understanding of brain mechanisms underlying the placebo response. ⋯ In general, placebo responses seem mediated by "top-down" processes dependent on frontal cortical areas that generate and maintain cognitive expectancies. Dopaminergic reward pathways may underlie these expectancies. Placebo-induced clinical benefits also involve disorder-specific neuronal responses, yielding neurofunctional or neurochemical alterations similar to those produced by pharmacological treatments.
-
Eur Neuropsychopharmacol · Jul 2008
ReviewECNP consensus meeting. Bipolar depression. Nice, March 2007.
DSM-IV, specifically its text revision DSM-IV-TR, remains the preferred diagnostic system. When employed in general population samples, prevalence estimates of bipolar disorder are relatively consistent across studies in Europe and USA. In community studies, first onset of bipolar mood disorder is usually in the mid-teenage years and twenties, and the occurrence of a major depressive episode or hypomania is usually its first manifestation. ⋯ Longer periods of stabilisation are also desirable for up to 3 months: protocol compliance may then be difficult to achieve in practice and so will certainly make studies more difficult and expensive to conduct. The addition of a medicine to other agents during or after the resolution of a depressive or manic episode, and its subsequent investigation as monotherapy against placebo to prevent further relapse (as in the lamotrigine maintenance trials) is clinically informative. Assay sensitivity and patient acceptability are enhanced if the outcome in long-term studies is 'time to intervention for a new episode' for discontinuation designs.
-
Eur Neuropsychopharmacol · Jun 2008
Meta AnalysisEfficacy of pregabalin in depressive symptoms associated with generalized anxiety disorder: a pooled analysis of 6 studies.
Epidemiological evidence supports comorbidity of generalized anxiety disorder (GAD) and major depressive disorder (MDD) or dysthymia, and its association with significant disability. As pregabalin, a new alpha(2)-delta anxiolytic treatment for GAD, unlike most other licensed treatments for GAD has not undergone investigation in patients with MDD, we examined its efficacy in depressive symptoms associated with GAD, through a post-hoc analysis of the existing clinical trial database. ⋯ Even in subjects with more prominent depressive symptoms, pregabalin remained effective for both sub-syndromal depression and GAD symptoms, with pregabalin 300-450 mg/day demonstrating the most beneficial response. In conclusion, pregabalin, an alternative treatment option for GAD with a novel mechanism of action, also demonstrated efficacy in treating depressive symptoms typically encountered in GAD patients.
-
Eur Neuropsychopharmacol · May 2008
Nitric oxide involvement in the antidepressant-like effects of acute lithium administration in the mouse forced swimming test.
In the present study we evaluated the involvement of l-arginine/nitric oxide (NO)/cGMP pathway in the antidepressant-like effects of acute lithium administration in the mouse forced swimming test (FST). Lithium, at 30 and 100 mg/kg, significantly reduced the immobility times of mice in the FST, whereas at lower doses (0.5, 5 and 10 mg/kg) had no effect on the immobility time. The NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), at 10 and 30 mg/kg, and the selective neuronal NOS inhibitor N(omega)-propyl-L-arginine (L-NPA), at 5 and 15 mg/kg, had no significant effects on the FST, whereas they significantly decreased the immobility time at 100 and 30 mg/kg, respectively. ⋯ Non-effective doses of L-arginine (750 mg/kg) or sildenafil (5 mg/kg) significantly reversed the antidepressant-like effect of 30 mg/kg lithium in the FST. Neither of the drugs had effect on the locomotor activity. These data indicate the involvement of L-arginine/NO/cGMP pathway in the antidepressant-like effect of lithium in the mouse FST and also might suggest the concurrent administration of NOS inhibitors and lithium as an appropriate strategy for treatment of depression.