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Objectives: We aimed to set up a robust multi-centre clinical fMRI and neuropsychological platform to investigate the neuropharmacology of brain processes relevant to addiction - reward, impulsivity and emotional reactivity. Here we provide an overview of the fMRI battery, carried out across three centres, characterizing neuronal response to the tasks, along with exploring inter-centre differences in healthy participants.Experimental Design: Three fMRI tasks were used: monetary incentive delay to probe reward sensitivity, go/no-go to probe impulsivity and an evocative images task to probe emotional reactivity. A coordinate-based activation likelihood estimation (ALE) meta-analysis was carried out for the reward and impulsivity tasks to help establish region of interest (ROI) placement. A group of healthy participants was recruited from across three centres (total n=43) to investigate inter-centre differences. Principle observations: The pattern of response observed for each of the three tasks was consistent with previous studies using similar paradigms. At the whole brain level, significant differences were not observed between centres for any task.Conclusions: In developing this platform we successfully integrated neuroimaging data from three centres, adapted validated tasks and applied whole brain and ROI approaches to explore and demonstrate their consistency across centres. [ABSTRACT FROM AUTHOR]

The present double-blind, placebo-controlled study evaluates the effects of agomelatine and the selective serotonin reuptake inhibitor escitalopram on sexual dysfunction in healthy men and women.Methods: A total of 133 healthy volunteers (67 men, 66 women) were randomly assigned to agomelatine (25 or 50 mg) or escitalopram (20 mg) or placebo for nine weeks. Sexual acceptability was evaluated by using the psychotropic-related sexual dysfunction questionnaire 5-items total score and sexual dysfunction relative to each sub-score (in 110 volunteers with sexual activity). Sexual dysfunction was evaluated at baseline and after two, five and eight weeks of treatment and one week after drug discontinuation.Results: The psychotropic-related sexual dysfunction questionnaire 5-items total score was significantly lower in both agomelatine groups versus escitalopram at all visits (p < 0.01 to p < 0.0001) with no difference between agomelatine and placebo nor between both agomelatine doses. Similar results were observed after drug discontinuation. The total score was significantly higher in the escitalopram group than in the placebo group at each post-baseline visit (p < 0.01 to p < 0.001). Similar results were observed regardless of volunteers' gender. Compared to placebo, only escitalopram significantly impaired dysfunction relative to "delayed orgasm or ejaculation" (p < 0.01) and "absence of orgasm or ejaculation" (p < 0.05 to p < 0.01). The percentage of participants with a sexual dysfunction was higher in the escitalopram group than in agomelatine groups (p < 0.01 to p < 0.05) and placebo (p < 0.01).Conclusion: The study confirms the better sexual acceptability profile of agomelatine (25 or 50 mg) in healthy men and women, compared to escitalopram.Trial Registration Name: Evaluation of the effect of agomelatine and escitalopram on emotions and motivation in healthy male and female volunteers.Trial Registration Number: ISRCTN75872983. [ABSTRACT FROM AUTHOR]

The glutamate hyperfunction hypothesis of schizophrenia has been proposed largely on the basis of studies in post-mortem brain and the lack of efficacy of glutamate agonists as antipsychotic drugs. Recent reports have also suggested that the addition of lamotrigine, a glutamate excess release inhibitor, can cause a dramatic improvement in clozapine treatment-resistant patients, as well as attenuate the neuropsychiatric effects of ketamine in healthy volunteers. To explore the glutamate hyperfunction hypothesis, patients with schizophrenia who were treatment-resistant to current antipsychotic medications were augmented with either lamotrigine (n = 17) or topiramate (a glutamate kainate/alpha-amino-3-hydroxy-5-methyl-4-isoxazolaproprionate antagonist that potentiates GABA function) (n = 9) for 24 weeks. Patients receiving lamotrigine augmentation of clozapine had a significant decrease in Brief Psychiatric Rating Scale score after 2 weeks of treatment. There was no significant improvement when lamotrigine was added to risperidone, haloperidol, olanzapine or fluphenthixol. There was also no significant improvement observed with topiramate augmentation of clozapine, olanzapine, haloperidol and fluphenthixol. These preliminary data support previous evidence that lamotrigine is an effective augmentation agent for clozapine. Although limited by sample size, the findings also suggest glutamate hyperfunction in schizophrenia may have a presynaptic basis and that atypicals with low dopamine receptor occupancy may have antagonistic actions on glutamate function which confer additional antipsychotic activity. [ABSTRACT FROM AUTHOR]

A revision of the British Association for Psychopharmacology guidelines for treating depressive disorders with antidepressants was undertaken in order to specify the scope and target of the guidelines and to update the recommendations based explicitly on the available evidence. A consensus meeting, involving experts in depressive disorders and their treatment, reviewed key areas and considered the strength of evidence and clinical implications. The guidelines were drawn up after extensive feedback from participants and interested parties. A literature review is given which identifies the quality of evidence followed by recommendations, the strength of which are based on the level of evidence. The guidelines cover the nature and detection of depressive disorders, acute treatment with antidepressant drugs, choice of drug versus alternative treatment, practical issues in prescribing, management when initial treatment fails, continuation treatment, maintenance treatment to prevent recurrence and stopping treatment. [ABSTRACT FROM AUTHOR]

The effects of buspirone, fluvoxamine and diazepam were investigated, using healthy volunteers, in an aversive conditioning paradigm, a putative model for conditioned anxiety. The main prediction was that buspirone, an anxiolytic agent which reduces activity in serotonin (5-hydroxytryptophan, 5-HT) neurones, would attenuate aversively conditioned skin conductance responses. Skin conductance responses were recorded to 10 neutral tones (habituation phase). Tone 11 was immediately followed by a 1-s 90-dB aversive white noise (unconditioned stimulus). The conditioning trial reinstated responding to a second presentation of the tones (extinction phase). Skin conductance response amplitude, inter-response level and spontaneous fluctuations were recorded. There were five treatment groups comprising five men and five women. One control group took placebo, another control group received nothing; there was no effect of placebo on any measure. Diazepam (2 mg, p.o.), a positive comparator, markedly reduced the amplitude of skin conductance responses at all phases of the experiment, but only in women. Buspirone (5 mg, p.o.) had the predicted effect of accelerating extinction but also of unexpectedly accelerated habituation of skin conductance responses. There was a trend to reduce spontaneous fluctuations and no effect on skin conductance level. The effects of buspirone were thus specific to responses to stimuli. Fluvoxamine (25 mg, p.o.) had similar effects to buspirone and diazepam in women. An action common to buspirone, fluvoxamine and diazepam, which may account for their shared effect on conditioned autonomic responses, is the suppression of neural activity in the dorsal raphe nucleus. It is argued that enhanced habituation must involve a different mechanism, such as enhanced 5-HT1A function in the terminal fields of the median raphe nucleus. [ABSTRACT FROM AUTHOR]

The article offers information on Great Britain-based medical program Sequenced Treatment Alternatives to Relieve Depression. As reported, in this program a clinical trial of 35 million dollars was carried out in which commonly used antidepressants were compared. It was seen that there was no significant differences between drugs in each step in the primary outcome measure. The core findings revealed the differences in response, remission and side effects.

Previous research has demonstrated that drug cues are able to capture attentional resources in addicted populations. However, few studies have controlled for the possibility that drug users find all motivationally significant (i.e., affective) stimuli particularly salient. We examined this issue in opiate addiction, by exploring the impact of drug-related and affective stimuli on central attentional processes. Sixteen male heroin addicts (seven on opiate pharmacotherapy and nine recently detoxified subjects) and 12 matched controls were studied. Subjects were fitted with a 32-channel electrode cap and were instructed to passively view a series of neutral, affective and opiate-related images. The P300 elicited by drug-related stimuli was significantly larger than that elicited by affective and neutral stimuli in opiate users but not controls. Baseline ratings of craving were also found to predict the degree of P300 facilitation to the drug-related stimuli in the addicted group. Further, the opiate group demonstrated an absence of the typical enhancement of ERP responses to non-drug affective stimuli. These results suggest that opiate addicts demonstrate greater cortical processing of drug cues than other types of affective stimuli. Further research is required to assess whether addiction is specifically associated with reduced sensitivity to natural rewards, aversive stimuli or affective cues in general. [ABSTRACT FROM AUTHOR]

Acute dietary tyrosine depletion has previously been shown to reduce dopamine neurotransmission in both animals and humans. In this study, we investigated the effects of brain dopamine depletion, through acute tyrosine and phenylalanine depletion, on plasma prolactin, mood and neuropsychological function in 12 normal subjects. In a randomized, double-blind, cross-over design, subjects received two amino-acid drinks separated by a week, a nutritionally balanced mixture (Bal) and on the other occasion a tyrosine and phenylalanine deficient mixture (TP-). The plasma ratio of tyrosine and phenylalanine to the other large neutral amino acids decreased significantly on the TP- occasion (-78.7%, p < 0.0001) and there was an increase in plasma prolactin concentration relative to the balanced drink in the seven subjects for whom results were available for both occasions (p < 0.02). Acute tyrosine depletion did not alter mood as measured by visual analogue scale ratings, and measures of memory, attention and behavioural inhibition were also unaffected. Our results are consistent with acute dietary tyrosine depletion causing a reduction in brain dopamine neurotransmission but raise questions about how robust or consistent the effects are on psychological function. [ABSTRACT FROM AUTHOR]

Increasing attention is being directed towards the role of the serotonergic system in the neurochemistry of schizophrenia and antipsychotic drug treatment. This review considers the 5-HT1A receptor in this context. In patients with schizophrenia, the majority of post-mortem studies have reported increases in 5-HT1A receptor density in the prefrontal cortex in the approximate range 15-80%. Although the pathophysiological significance of this finding is unclear, given the location of a major proportion of these receptors on pyramidal cells, it may reflect an abnormal glutamatergic network. In terms of drug treatment, 5-HT1A agonists clearly display anticataleptic activity in rats. In addition, 5-HT1A agonists consistently increase dopamine release in the prefrontal cortex in rodents, which is an effect that might be predicted to improve negative symptoms. 5-HT1A agonists augment classical neuroleptics in some rat models of antipsychotic action and may be capable of modulating the glutamatergic network therapeutically. Despite the encouraging preclinical data, there is a paucity of clinical studies of 5-HT1A agonist augmentation of neuroleptics in the treatment of schizophrenia. However, the clinical relevance may be clarified by the atypical antipsychotic drugs clozapine, quetiapine and ziprasidone which combine D2 receptor antagonism and 5-HT1A agonism. In conclusion, given the increased prefrontal 5-HT1A receptor density in the illness, and the anticataleptic activity of 5-HT1A agonists combined with their ability to evoke prefrontal dopamine release, there is now a sufficient rationale to examine thoroughly the role of the 5-HT1A receptor in schizophrenia and antipsychotic drug treatment. [ABSTRACT FROM AUTHOR]

Increasing attention is being directed towards the role of the serotonergic system in the neurochemistry of schizophrenia and antipsychotic drug treatment. This review considers the 5-HT 1A receptor in this context. In patients with schizophrenia, the majority of post-mortem studies have reported increases in 5-HT 1A receptor density in the prefrontal cortex in the approximate range 15--80%. Although the pathophysiological significance of this finding is unclear, given the location of a major proportion of these receptors on pyramidal cells, it may reflect an abnormal glutamatergic network. In terms of drug treatment, 5-HT [sub1A] agonists clearly display anticataleptic activity in rats. In addition, 5-HT [sub1A] agonists consistently increase dopamine release in the prefrontal cortex in rodents, which is an effect that might be predicted to improve negative symptoms. 5-HT [sub1A] agonists augment classical neuroleptics in some rat models of antipsychotic action and may be capable of modulating the glutamatergic network therapeutically. Despite the encouraging preclinical data, there is a paucity of clinical studies of 5-HT[sub1A] agonist augmentation of neuroleptics in the treatment of schizophrenia. However, the clinical relevance may be clarified by the atypical antipsychotic drugs clozapine, quetiapine and ziprasidone which combine D 2 receptor antagonism and 5-HT[sub1A] agonism. In conclusion, given the increased prefrontal 5-HT[sub1A] receptor density in the illness, and the anticataleptic activity of 5-HT[sub1A] agonists combined with their ability to evoke prefrontal dopamine release, there is now a sufficient rationale to examine thoroughly the role of the 5-HT[sub1A] receptor in schizophrenia and antipsychotic drug treatment. [ABSTRACT FROM AUTHOR]

Background Identifying the neural correlates of ketamine treatment may facilitate and expedite the development of novel, robust, and safe rapid-acting antidepressants. Prefrontal cortex (PFC) global brain connectivity with global signal regression (GBCr) was recently identified as a putative biomarker of major depressive disorder. Accumulating evidence have repeatedly shown reduced PFC GBCr in major depressive disorder, an abnormality that appears to normalize following ketamine treatment. Methods Fifty-six unmedicated participants with major depressive disorder were randomized to intravenous placebo (normal saline; n = 18), ketamine (0.5 mg/kg; n = 19), or lanicemine (100 mg; n = 19). PFC GBCr was computed using time series from functional magnetic resonance imaging scans that were completed at baseline, during infusion, and at 24-h posttreatment. Results Compared to placebo, ketamine significantly increased average PFC GBCr during infusion (p = 0.01) and at 24-h posttreatment (p = 0.02). Lanicemine had no significant effects on GBCr during infusion (p = 0.45) and at 24-h posttreatment (p = 0.23) compared to placebo. Average delta PFC GBCr (during minus baseline) showed a pattern of positively predicting depression improvement in participants receiving ketamine (r = 0.44; p = 0.06; d = 1.0) or lanicemine (r = 0.55; p = 0.01; d = 1.3) but not those receiving placebo (r = −0.1; p = 0.69; d = 0.02). Follow-up vertex-wise analyses showed ketamine-induced GBCr increases in the dorsolateral, dorsomedial, and frontomedial PFC during infusion and in the dorsolateral and dorsomedial PFC at 24-h posttreatment (corrected p < 0.05). Exploratory vertex-wise analyses examining the relationship with depression improvement showed positive correlation with GBCr in the dorsal PFC during infusion and at 24-h posttreatment but negative correlation with GBCr in the ventral PFC during infusion (uncorrected p < 0.01). Conclusions In a randomized placebo-controlled approach, the results provide the first evidence in major depressive disorder of ketamine-induced increases in PFC GBCr during infusion and suggest that ketamine's rapid-acting antidepressant properties are related to its acute effects on prefrontal connectivity. Overall, the study findings underscore the similarity and differences between ketamine and another N-methyl-D-aspartate receptor antagonist while proposing a pharmacoimaging paradigm for the optimization of novel rapid-acting antidepressants prior to testing in costly clinical trials. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor in response to an article about the use of acute tryptophan or tyrosine depletion test in assessing behavioral and psychological disorders, published in the "Journal of Psychopharmacology."