Acute SSRI administration affects the processing of social cues in healthy volunteers

Short- and long-term functional consequences of fluoxetine exposure during adolescence in male rats

BACKGROUND

Fluoxetine (FLX), a selective serotonin reuptake inhibitor, is prescribed for the treatment of major depressive disorder in young populations. Here, we explore the short- and long-term consequences of adolescent exposure to FLX on behavioral reactivity to emotion-eliciting stimuli.

METHODS

Adolescent male rats received FLX (10 mg/kg) twice daily for 15 consecutive days (postnatal days 35-49). The influence of FLX on behavioral reactivity to rewarding and aversive stimuli was assessed 24 hours (short-term) or 3 weeks after FLX treatment (long-term). A separate group of adult rats was also treated with FLX (postnatal days 65-79) and responsiveness to forced swimming was assessed at identical time intervals as with the adolescents.

RESULTS

Fluoxetine exposure during adolescence resulted in long-lasting decreases in behavioral reactivity to forced swimming stress and enhanced sensitivity to sucrose and to anxiety-eliciting situations in adulthood. The FLX-induced anxiety-like behavior was alleviated by re-exposure to FLX in adulthood. Fluoxetine treatment during adolescence also impaired sexual copulatory behaviors in adulthood. Fluoxetine-treated adult rats did not show changes in behavioral reactivity to forced swim stress as observed in those treated during adolescence and tested in adulthood.

CONCLUSIONS

Treating adolescent rats with FLX results in long-lived complex outputs regulated by the emotional valence of the stimulus, the environment in which it is experienced, and the brain circuitry likely being engaged by it. Our findings highlight the need for further research to improve our understanding of the alterations that psychotropic exposure may induce on the developing nervous system and the potential enduring effects resulting from such treatments.

Erythropoietin modulates neural and cognitive processing of emotional information in biomarker models of antidepressant drug action in depressed patients

OBJECTIVE

Erythropoietin (Epo) has neuroprotective and neurotrophic effects, and may be a novel therapeutic agent in the treatment of psychiatric disorders. We have demonstrated antidepressant-like effects of Epo on the neural and cognitive processing of facial expressions in healthy volunteers. The current study investigates the effects of Epo on the neural and cognitive response to emotional facial expressions in depressed patients.

METHOD

Nineteen acutely depressed patients were randomized to receive Epo (40,000 IU) or saline intravenously in a double-blind, parallel-group design. On day 3, we assessed neuronal responses to fearful and happy faces using functional magnetic resonance imaging and measured facial expression recognition after the scan.

RESULTS

Epo reduced neural response to fearful vs. happy faces in the amygdala and hippocampus, and to fearful faces vs. baseline in superior temporal and occipitoparietal regions 3 days after administration in acutely depressed patients. This was accompanied by a specific reduction in the recognition of fear in Epo-treated patients after the scan similar to the effects on face recognition seen with antidepressant drug treatment.

CONCLUSIONS

The present findings are similar to the effects of conventional antidepressants in acutely depressed patients and opposite to hypervigilance to negative facial expressions in depression. This highlights a potential antidepressant mechanism and warrants further investigation of Epo as a new candidate compound for treatment of depression.

Decreased recognition of negative affect after selective serotonin reuptake inhibition is dependent on genotype

Selective serotonin reuptake inhibitors (SSRIs) are known to influence the information processing of emotional material in depressed patients and healthy controls. The functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) has been shown to interact with the effectiveness of serotonin reuptake inhibitors. It is not known whether 5-HTTLPR has an influence on emotional processing in healthy controls. We report first data with long-term SSRI administration after genetic characterization of 5-HTTLPR in a randomized, double-blind, placebo-controlled, crossover design. In 30 healthy controls, 15 homozygous for the long and 15 for the short allele of 5-HTTLPR, emotionally valent images were used to elicit positive or negative emotions. We found a diminished perception of sad and fearful information under SSRI which was significant in the long allele group. These findings emphasize the importance of genetic variance in emotion processing research.

Escitalopram attenuates posterior cingulate activity during self-evaluation in healthy volunteers

Medial cortex is critically involved in self-referential processing. Little is known about how selective serotonin reuptake inhibitors (SSRIs) affect medial cortical activity during self-assessment. We hypothesized that a 3-week oral course of escitalopram,10 mg/day, would alter activity related to self-referential processing in medial cortex. Fifteen healthy females performed a self-assessment task during functional magnetic resonance imaging on two occasions--once after 3 weeks of placebo and once at the end of 3 weeks of escitalopram. Task conditions involved responding "yes" or "no" to whether various positive and negative adjectives described the subject (i.e., "self" evaluation trials) or the subject's best friend (i.e., "other" evaluation trials), whereas the comparison condition involved responding whether the valence of various adjectives was positive or negative (i.e., "word" evaluation trials). Behaviorally after escitalopram, subjects less frequently endorsed that negative adjectives described themselves. Three main neuroimaging results were observed: (1) increased activation in medial prefrontal cortex and posterior cingulate related to self minus word evaluation trials, (2) increased activation in posterior cingulate related to escitalopram minus placebo for self and word evaluation trials, and (3) drug by task interactions in the insula, cerebellum and prefrontal cortex. These results show that SSRIs change medial cortical activity and may alter self-evaluation.

Escitalopram prolonged fear induced by simulated public speaking and released hypothalamic-pituitary-adrenal axis activation

Simulated public speaking (SPS) test is sensitive to drugs that interfere with serotonin-mediated neurotransmission and is supposed to recruit neural systems involved in panic disorder. The study was aimed at evaluating the effects of escitalopram, the most selective serotonin-selective reuptake inhibitor available, in SPS. Healthy males received, in a double-blind, randomized design, placebo (n = 12), 10 (n = 17) or 20 (n = 14) mg of escitalopram 2 hours before the test. Behavioural, autonomic and neuroendocrine measures were assessed. Both doses of escitalopram did not produce any effect before or during the speech but prolonged the fear induced by SPS. The test itself did not significantly change cortisol and prolactin levels but under the higher dose of escitalopram, cortisol and prolactin increased immediately after SPS. This fear-enhancing effect of escitalopram agrees with previously reported results with less selective serotonin reuptake inhibitors and the receptor antagonist ritanserin, indicating that serotonin inhibits the fear of speaking in public.

NK1 receptor antagonism and emotional processing in healthy volunteers

The neurokinin-1 (NK(1)) receptor antagonist, aprepitant, showed activity in several animal models of depression; however, its efficacy in clinical trials was disappointing. There is little knowledge of the role of NK(1) receptors in human emotional behaviour to help explain this discrepancy. The aim of the current study was to assess the effects of a single oral dose of aprepitant (125 mg) on models of emotional processing sensitive to conventional antidepressant drug administration in 38 healthy volunteers, randomly allocated to receive aprepitant or placebo in a between groups double blind design. Performance on measures of facial expression recognition, emotional categorisation, memory and attentional visual-probe were assessed following the drug absorption. Relative to placebo, aprepitant improved recognition of happy facial expressions and increased vigilance to emotional information in the unmasked condition of the visual probe task. In contrast, aprepitant impaired emotional memory and slowed responses in the facial expression recognition task suggesting possible deleterious effects on cognition. These results suggest that while antagonism of NK(1) receptors does affect emotional processing in humans, its effects are more restricted and less consistent across tasks than those of conventional antidepressants. Human models of emotional processing may provide a useful means of assessing the likely therapeutic potential of new treatments for depression.

Investigating vulnerability to eating disorders: biases in emotional processing

BACKGROUND

Biases in emotional processing and cognitions about the self are thought to play a role in the maintenance of eating disorders (EDs). However, little is known about whether these difficulties exist pre-morbidly and how they might contribute to risk.

METHOD

Female dieters (n=82) completed a battery of tasks designed to assess the processing of social cues (facial emotion recognition), cognitions about the self [Self-Schema Processing Task (SSPT)] and ED-specific cognitions about eating, weight and shape (emotional Stroop). The 26-item Eating Attitudes Test (EAT-26; Garner et al. 1982) was used to assess subclinical ED symptoms; this was used as an index of vulnerability within this at-risk group.

RESULTS

Regression analyses showed that biases in the processing of both neutral and angry faces were predictive of our measure of vulnerability (EAT-26). In the self-schema task, biases in the processing of negative self descriptors previously found to be common in EDs predicted vulnerability. Biases in the processing of shape-related words on the Stroop task were also predictive; however, these biases were more important in dieters who also displayed biases in the self-schema task. We were also able to demonstrate that these biases are specific and separable from more general negative biases that could be attributed to depressive symptoms.

CONCLUSIONS

These results suggest that specific biases in the processing of social cues, cognitions about the self, and also about eating, weight and shape information, may be important in understanding risk and preventing relapse in EDs.

Risperidone versus haloperidol for facial affect recognition in schizophrenia: findings from a randomised study

Patients with schizophrenia consistently fail to perform facial affect recognition tasks as accurately as healthy controls. So far, the effects of different antipsychotic drugs on this deficit, as well as the mechanisms through which these drugs may exert their influence on face processing models, remain poorly understood. Twenty-five hospitalised acute schizophrenic patients were randomised to either haloperidol or risperidone following their admission. Patients performed a facial affect discrimination task. In order to differentiate drug effects on perceptive versus semantic processing of faces, the evaluation also included two facial identity discrimination tasks (inverted and upright faces). All evaluations were performed before treatment initiation, after 2 weeks and after 4 weeks of treatment. Compared with patients receiving haloperidol, patients receiving risperidone showed better discrimination of facial affect and inverted faces, but not of upright faces. Differential drug effects were most prominent 2 weeks after treatment initiation. Performance on inverted faces accounted for only 1% of the variance in affect discrimination. Additionally, there was an inverse relationship between negative symptoms and performance on upright-face identification and affect discrimination, with the strongest and most significant correlation being for affect discrimination. Our findings suggest that the preferential effect of risperidone on affect discrimination is unlikely to be due to global effects on general face processing. Moreover, although risperidone appears to enhance the processing of individual salient facial features, this effect cannot explain the improvement in affect recognition. We conclude that risperidone may specifically act on the processing of emotion-laden information.

Oxytocin and Major Depressive Disorder: Experimental and Clinical Evidence for Links to Aetiology and Possible Treatment

Affective disorders represent the most common psychiatric diseases, with substantial co-morbidity existing between major depressive disorders (MDD) and anxiety disorders. The lack of truly novel acting compounds has led to non-monoaminergic based research and hypotheses in recent years. The large number of brain neuropeptides, characterized by discrete synthesis sites and multiple receptors, represent likely research candidates for novel therapeutic targets. The present review summarises the available preclinical and human evidence regarding the neuropeptide, oxytocin, and its implications in the aetiology and treatment of MDD. While the evidence is not conclusive at present additional studies are warranted to determine whether OXT may be of therapeutic benefit in subsets of MDD patients such as those with comorbid anxiety symptoms and low levels of social attachment.

Effect of escitalopram on the processing of emotional faces

Serotonin has been implicated in the neurobiology of depressive and anxiety disorders, but little is known about its role in the modulation of basic emotional processing. The aim of this study was to determine the effect of the selective serotonin reuptake inhibitor, escitalopram, on the perception of facial emotional expressions. Twelve healthy male volunteers completed two experimental sessions each, in a randomized, balanced order, double-blind design. A single oral dose of escitalopram (10 mg) or placebo was administered 3 h before the task. Participants were presented to a task composed of six basic emotions (anger, disgust, fear, happiness, sadness, and surprise) that were morphed between neutral and each standard emotion in 10% steps. Escitalopram facilitated the recognition of sadness and inhibited the recognition of happiness in male, but not female faces. No drug effect on subjective measures was detected. These results confirm that serotonin modulates the recognition of emotional faces, and suggest that the gender of the face can have a role in this modulation. Further studies including female volunteers are needed.

Effects of paroxetine on emotional functioning and treatment awareness: a 4-week randomized placebo-controlled study in healthy clinicians

OBJECTIVE

The objective of our study was to evaluate the effects of paroxetine on emotional functioning in three arms: double-blind paroxetine (DBPX), single-blind paroxetine (SBPX), and double-blind placebo (DBPO). Healthy psychologists and psychiatrists were elected for their ability to analyze with correct sensibility changes in their emotions.

METHOD

Thirty nonanxious, nondepressed participants working as psychiatrists (N = 18) or psychologists (N = 12) were randomly assigned to receive an ambulatory treatment with paroxetine (DBPX N = 10, SBPX N = 10) or placebo (DBPO N = 10). Paroxetine was administered for 4 weeks at 20 mg/day. Emotional functioning was evaluated with the Emotional State Questionnaire (ESQ), a self-questionnaire designed to assess four emotional dimensions: "recognition," "expression," "internal emotional experience," and "social context." Changes in emotional measures from baseline to D0, D7, D14, D28, and D42 were compared between treatment groups.

RESULTS

Analyses of ESQ showed in DBPX a significant decrease from baseline to D28 in internal emotional experience as compared to SBPX and DBPO groups. A different influence of gender between treatment groups on emotional recognition was observed.

CONCLUSIONS

This is the first study assessing the impact of a 4-week paroxetine treatment on emotional functioning in healthy psychiatrists and psychologists. The DBPX group was distinguishable from both SBPX and DBPO groups by a decrease in internal emotional experience, suggesting that two factors could be involved in the clinical response to paroxetine: a decrease in emotional feeling and treatment awareness.

Serotonergic and noradrenergic modulation of emotion processing by single dose antidepressants

Serotonergic and noradrenergic pathways are the main targets of antidepressants. Their differential effects on emotion processing-related brain activation are, however, to be further characterized. We aimed at elucidating the neural sites of action of an acute differential serotonergic and noradrenergic influence on an emotion-processing task, which was earlier shown to be associated with depressiveness. In a single-blind pseudo-randomized crossover study, 21 healthy subjects (16 subjects finally included in the analysis) participated to ingest a single dose at three time points of either 40 mg citalopram, a selective serotonin-reuptake inhibitor, 8 mg reboxetine, a selective noradrenaline-reuptake inhibitor, or placebo 2-3 h before functional magnetic resonance imaging (fMRI). During fMRI, subjects performed a task comprising the anticipation and perception of pictures of either 'known' (positive, negative, neutral) or 'unknown' valence (randomly 50% positive or negative). In direct comparison with citalopram and with placebo, reboxetine increased brain activity in the medial thalamus. Citalopram modulated certain prefrontal and insular areas more prominently. Other frontal and parieto-occipital areas were modulated by both drugs. In conclusion, the functional network involved in emotional information processing could be modulated by the acute application of selective noradrenergic and serotonergic drugs revealing a noradrenergic effect in thalamic and frontal areas, and a prefrontal and insular focus of serotonergic modulation. These findings could have implications for future selection criteria concerning personalized antidepressant medication in depression.

The effect of serotonergic and noradrenergic antidepressants on face emotion processing in depressed patients

BACKGROUND

In healthy volunteers, exposure to antidepressants increases the recognition of positive face emotions and decreases recognition of negative emotions. It has been proposed that this may underlie therapeutic effects of antidepressants, but to date this has not been tested in clinical populations.

METHOD

Recognition of facial emotions was measured at baseline (N=108) and after 2 (N=59) and 6 weeks (N=69) of treatment in depressed primary care patients who had been randomised to treatment with either citalopram (SSRI) or reboxetine (NaRI) in an open-label study. Changes in emotional processing were compared to clinical outcome after 6 weeks of treatment.

RESULTS

Significant increases in recognition accuracy of disgust, happiness and surprise occurred by two-weeks of treatment with both antidepressants, and did not further change at 6 weeks. There was a significant correlation between the increased accuracy in recognition of happy faces over the first two-weeks of treatment and the clinical improvement after six-weeks of treatment.

LIMITATIONS

There was no control group and changes over time may be due to practice effects.

CONCLUSIONS

Antidepressants altered emotional processing in depressed patients with some similarities to the effects seen in healthy volunteers. The largest effect seen was increased recognition of disgust that may be specific to depressed patients. The correlation between increased accurate recognition of happy faces at two-weeks of treatment and clinical outcome at six-weeks of treatment suggests that early changes in emotional processing may underlie clinical response to antidepressants.

Effects of erythropoietin on emotional processing biases in patients with major depression: an exploratory fMRI study

INTRODUCTION

Erythropoietin (Epo) has neurotrophic effects and may be a novel therapeutic agent in the treatment of depression. We have found antidepressant-like effects of Epo on emotional processing and mood in healthy volunteers.

OBJECTIVE

The current study aimed to explore the effects of Epo on the neural processing of emotional information in depressed patients.

MATERIALS AND METHODS

Seventeen patients with acute major depressive disorder were randomised to receive Epo (40,000 IU) or saline iv in a double-blind, parallel-group design. On day 3, we assessed neural responses to positive, negative and neutral pictures during fMRI followed by picture recall after the scan. Mood and blood parameters were assessed at baseline and on day 3.

RESULTS

Epo reduced neural response to negative vs. positive pictures 3 days post-administration in a network of areas including the hippocampus, ventromedial prefrontal and parietal cortex. After the scan, Epo-treated patients showed improved memory compared with those that were given placebo. The effects occurred in the absence of changes in mood or haematological parameters, suggesting that they originated from direct neurobiological actions of Epo.

CONCLUSIONS

These findings are similar to the effects of conventional antidepressants and opposite to the negative biases in depression. The central effects of Epo therefore deserve further investigation as a potential antidepressant mechanism.

The role of serotonin in nonnormative risky choice: the effects of tryptophan supplements on the "reflection effect" in healthy adult volunteers

Risky decision-making involves weighing good and bad outcomes against their probabilities in order to determine the relative values of candidate actions. Although human decision-making sometimes conforms to rational models of how this weighting is achieved, irrational (or nonnormative) patterns of risky choice, including shifts between risk-averse and risk-seeking choices involving equivalent-value gambles (the "reflection effect"), are frequently observed. In the present experiment, we investigated the role of serotonin in decision-making under conditions of uncertainty. Fifteen healthy adult volunteers received a treatment of 3 g per day of the serotonin precursor, tryptophan, in the form of dietary supplements over a 14-day period, whereas 15 age- and IQ-matched control volunteers received a matched placebo substance. At test, all participants completed a risky decision-making task involving a series of choices between two simultaneously presented gambles, differing in the magnitude of their possible gains, the magnitude of their possible losses, and the probabilities with which these outcomes were delivered. Tryptophan supplements were associated with alterations in the weighting of gains and small losses perhaps reflecting reduced loss-aversion, and a marked and significant diminution of the reflection effect. We conclude that serotonin activity plays a significant role in nonnormative risky decision-making under conditions of uncertainty.

NK1 receptor antagonism and the neural processing of emotional information in healthy volunteers

The neuropeptide substance P and its receptor NK1 have been implicated in emotion, anxiety and stress in preclinical studies. However, the role of NK1 receptors in human brain function is less clear and there have been inconsistent reports of the value of NK1 receptor antagonists in the treatment of clinical depression. The present study therefore aimed to investigate effects of NK1 antagonism on the neural processing of emotional information in healthy volunteers. Twenty-four participants were randomized to receive a single dose of aprepitant (125 mg) or placebo. Approximately 4 h later, neural responses during facial expression processing and an emotional counting Stroop word task were assessed using fMRI. Mood and subjective experience were also measured using self-report scales. As expected a single dose of aprepitant did not affect mood and subjective state in the healthy volunteers. However, NK1 antagonism increased responses specifically during the presentation of happy facial expressions in both the rostral anterior cingulate and the right amygdala. In the emotional counting Stroop task the aprepitant group had increased activation in both the medial orbitofrontal cortex and the precuneus cortex to positive vs. neutral words. These results suggest consistent effects of NK1 antagonism on neural responses to positive affective information in two different paradigms. Such findings confirm animal studies which support a role for NK1 receptors in emotion. Such an approach may be useful in understanding the effects of novel drug treatments prior to full-scale clinical trials.

A new ethics of psychiatry: neuroethics, neuroscience, and technology

Neuroethics is a new subset of bioethics that addresses ethical issues pertaining to the brain, primarily in the fields of neuroscience, cognitive science, and neuroradiology. Research in brain science is progressing at a phenomenal rate and, as a result, the acquisition and application of knowledge and technology raises ethical questions of a practical and philosophical nature. While neuroethics is developing as a distinct field of study, one area that should be addressed in greater depth is the relevance and potential impact of neurotechnology in psychiatry. New knowledge in the mind-brain conundrum and increasingly sophisticated techniques for imaging and intervening in human cognition, emotion, and behavior pose ethical issues at the intersection of technology and psychiatry. This article presents a broad survey of the new directions in neuroethics, neuroscience, and technology and considers the implications of technological advances for the practice of psychiatry in the new millennium. (Journal of Psychiatric Practice 2009;15:391-401).

Omega-3 fatty acids (fish-oil) and depression-related cognition in healthy volunteers

Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation may be beneficial in the treatment of several psychiatric disorders, including depression. A small number of studies have suggested that there may also be cognitive and mood effects in healthy samples. The purpose of the present study was to investigate the effects of n-3 PUFA on depression-relevant cognitive functioning in healthy individuals. Fifty-four healthy university students were randomized to receive either n-3 PUFA supplements or placebo for 4 weeks in a double-blind design. The test battery included measures of cognitive reactivity, attention, response inhibition, facial emotion recognition, memory and risky decision-making. Results showed few effects of n-3 PUFAs on cognition and mood states. The n-3 PUFA group made fewer risk-averse decisions than the placebo group. This difference appeared only in non-normative trials of the decision-making test, and was not accompanied by increased impulsiveness. N-3 PUFAs improved scores on the control/perfectionism scale of the cognitive reactivity measure. No effects were found on the other cognitive tasks and no consistent effects on mood were observed. The present findings indicate that n-3 PUFA supplementation may have a selective effect on risky decision making in healthy volunteers, which is unrelated to impulsiveness.

Emotional processing in women with anorexia nervosa and in healthy volunteers

Emotional processing was investigated in patients with anorexia nervosa (AN) and in healthy volunteers (HVs) using self report questionnaires and information processing tasks. Compared to the HVs, patients with AN had lower levels of self reported emotional awareness and expression. They also responded more slowly to, correctly identified fewer emotions and misclassified more emotions in a facial recognition task, and responded more slowly to, and recalled fewer, self-referent emotion words. There were no key differences between the two groups on non-emotional control tasks, suggesting that their deficits are specific to emotional information and not a general feature of the illness. Analysis indicated that some, but not all, of the differences found remained when depressive symptoms were taken into account. Exploratory analysis of sub-groups (medicated vs. unmedicated patients) indicated that those who were on medication may perform very differently from those who were not on medication, including when level of depression is controlled, although it is important to emphasise that these findings are preliminary. The implications of a deficit in emotional processing in those with AN, including discussion of the specific differences found between medicated and unmedicated, are discussed in relation to previous findings in the area. A number of implications for future research, theory and therapy with those with AN are discussed.

Why do antidepressants take so long to work? A cognitive neuropsychological model of antidepressant drug action

BACKGROUND

The neuropharmacological actions of antidepressants are well characterised but our understanding of how these changes translate into improved mood are still emerging.

AIMS

To investigate whether actions of antidepressant drugs on emotional processing are a mediating factor in the effects of these drugs in depression.

METHOD

We examined key published findings that explored the effects of antidepressants on behavioural and functional magnetic resonance imaging (fMRI) measures of emotional processing.

RESULTS

Negative emotional bias has been reliably associated with depression. Converging results suggest that antidepressants modulate emotional processing and increase positive emotional processing much earlier than effects on mood. These changes in emotional processing are associated with neural modulation in limbic and prefrontal circuitry.

CONCLUSIONS

Antidepressants may work in a manner consistent with cognitive theories of depression. Antidepressants do not act as direct mood enhancers but rather change the relative balance of positive to negative emotional processing, providing a platform for subsequent cognitive and psychological reconsolidation.

Erythropoietin induction by electroconvulsive seizure, gene regulation, and antidepressant-like behavioral effects

BACKGROUND

The neuroprotective and trophic actions of erythropoietin (EPO) have been tested in several animal models of insult, injury, and neurodegeneration. Recent studies in human volunteers demonstrated that EPO improves cognition and also elicits antidepressant effects. It is believed that the behavioral effects are mediated by EPO's trophic effect on neuronal systems. We therefore tested whether EPO is able to alter behavior and brain gene expression in rats.

METHODS

The expression of EPO and EPO receptor (EPOR) in multiple brain regions was examined by quantitative polymerase chain reaction, in situ hybridization, and immunohistochemistry. The regulation of EPO and the transcription factor hypoxia-induced factor-alpha (HIF1alpha) after electroconvulsive seizure (ECS) was investigated. Behavioral effects of EPO were tested in the rodent forced swimming and novelty-induced hypophagia (NIH) models. EPO gene profiles were obtained by microarray analysis of the hippocampus after intracerebroventricular infusion.

RESULTS

EPO and EPOR were widely expressed in the brain albeit at low levels. Highest level of EPO and EPOR were in the choroid plexus and striatum, respectively. Peripheral administration of EPO was sufficient to produce a robust antidepressant-like effect in the forced swim and NIH tests. Gene expression profiles revealed that EPO induces the expression of neurotrophic genes such as brain-derived neurotrophic factor, VGF (nonacronymic), and neuritin.

CONCLUSIONS

EPO is induced by ECS and independently exhibits antidepressant-like efficacy in the forced swim and NIH tests. EPO regulates the expression of genes implicated in antidepressant action and appears to be a candidate molecule for further testing in neuropsychiatry.

Impaired identification of fearful faces in Generalised Social Phobia

BACKGROUND

Cognitive models and interventions for anxiety assume that socially anxious individuals interpret ambiguous social information in a threatening manner. However, experimental evidence for this hypothesised cognitive bias is mixed. The present study is novel in using a signal detection approach to clarify whether Generalised Social Phobia (GSP) is associated with biased identification of emotionally ambiguous facial expressions.

METHODS

16 patients with GSP and 17 non-anxious volunteers classified ambiguous emotional facial expressions, with each face reflecting a blend of two emotions: angry-happy, fearful-happy and fearful-angry. Discrimination accuracy and response criterion were assessed.

RESULTS

Patients with GSP showed significantly poorer discrimination of ambiguous emotional facial expressions that contained an element of fear (i.e., fearful-happy and fearful-angry expressions), compared to non-anxious controls. The groups did not significantly differ in discrimination of faces which lacked fear content (i.e., angry-happy blend), or on measures of response criterion.

LIMITATIONS

Small sample size, coexisting depressive symptoms.

CONCLUSIONS

Findings indicate a selective impairment in fear identification in GSP. Results are discussed with reference to neurocognitive models of anxiety, and research on serotonergic modulation of emotional face processing.

Effect of a single dose of citalopram on amygdala response to emotional faces

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are typically thought to have a delay of several weeks in the onset of their clinical effects. However, recent reports suggest they may have a much earlier therapeutic onset. A reduction in amygdala responsivity has been implicated in the therapeutic action of SSRIs.

AIMS

To investigate the effect of a single dose of an SSRI on the amygdala response to emotional faces.

METHOD

Twenty-six healthy volunteers were randomised to receive a single oral dose of citalopram (20 mg) or placebo. Effects on the processing of facial expressions were assessed 3 h later using functional magnetic resonance imaging.

RESULTS

Volunteers treated with citalopram displayed a significantly reduced amygdala response to fearful facial expressions compared with placebo.

CONCLUSIONS

Such an immediate effect of an SSRI on amygdala responses to threat supports the idea that antidepressants have an earlier onset of therapeutically relevant effects than conventionally thought.

Early effects of mirtazapine on emotional processing

BACKGROUND

Acute administration of selective serotonin and noradrenaline re-uptake blockers to healthy volunteers affects the processing of emotional information but it is not known if similar effects occur with antidepressants acting through other pharmacological mechanisms. Mirtazapine is a clinically established antidepressant with complex actions involving blockade of noradrenaline alpha(2)-adrenoceptors as well as a number of 5-HT receptor subtypes. The aim of the present study was to test whether, like monoamine re-uptake inhibitors, mirtazapine would also produce positive biases in emotional processing.

METHODS

We studied 30 healthy volunteers who received either a single dose of mirtazapine (15 mg) or placebo in a parallel group, double-blind study. Two hours following medication administration, participants completed a battery of tasks testing various aspects of emotional processing including facial expression recognition, emotion potentiated startle, and emotional categorization and memory.

RESULTS

Compared to placebo, mirtazapine significantly impaired the recognition of fearful facial expressions and reduced eye-blink responses in the emotion potentiated startle task. Participants receiving mirtazapine were also significantly quicker to respond to emotional self-relevant information in the categorization task and showed a positive bias in memory recall compared to those receiving placebo.

CONCLUSIONS

Our findings indicate that mirtazapine reduces fear processing in healthy volunteers, an effect similar to that produced by repeated administration of selective serotonin re-uptake inhibitors. In addition, mirtazapine increased memory for likeable versus dislikeable self-relevant information suggesting an induction of positive bias in emotional memory. Such effects may be important for our understanding of the neuropsychological mechanisms of antidepressant action in both anxiety and depressive disorders.

Oxytocin enhances processing of positive versus negative emotional information in healthy male volunteers

Animal studies have shown the role of oxytocin in affiliation and attachment, and recent evidence suggests that oxytocin is also involved in human models of approach behaviour, possibly by modulating the processing of emotionally valenced stimuli. Although oxytocin administration has been reported to decrease neural responses to facial emotional information, the effects on a wider range of behavioural measures of emotional processing shown to be sensitive to antidepressant manipulation have not been examined. The aim of this study was to investigate whether intranasally administered oxytocin affects the processing of positive and negative affective information in healthy male volunteers across tasks measuring attention, perception and memory. Twenty-nine male healthy volunteers were randomly allocated to receive a single dose of oxytocin nasal spray (24 UI) or placebo. 50 min later, participants completed a battery of psychological tests measuring emotional processing. A single dose of intranasally administered oxytocin slowed reaction time to correctly identify fearful facial expressions and reduced the misclassification of positive emotions as negative ones. These effects occurred in the absence of significant differences in subjective ratings of mood and anxiety. These results suggest that oxytocin modulates emotion processing in healthy male volunteers. This action may contribute to the emerging role of the neuropeptide in promoting affiliative and approach behaviours by reducing the salience of potentially ambiguous and threatening social stimuli.

Putting pain assessment into practice: why is it so painful?

OBJECTIVE

To explore some of the reasons for poor compliance with the use of standardized pain assessment tools in clinical practice, despite numerous guidelines and standards mandating their use.

METHODS

First, a review of research and clinical audit literature on the effects of standardized pain assessment tools on patient or process outcomes was conducted, and findings were critiqued. Second, a synthesis of recent literature on the biopsychosocial mechanisms of human detection and recognition of pain in others was presented. Third, the implications for pain assessment in pediatric clinical settings were discussed.

RESULTS

There is a lack of good-quality evidence for the efficacy, effectiveness or cost-benefit of standardized pain assessment tools in relation to pediatric patient or process outcomes. Research suggests that there may be greater variability than previously appreciated in the ability and motivation of humans when assessing pain in others. It remains unknown whether pain detection skills or motivation to relieve pain in others can be improved or overcome by standardized methods of pain assessment.

DISCUSSION

Further research is needed to understand the intra- and interpersonal dynamics in clinical assessment of pain in children and to test alternative means of achieving diagnosis and treatment of pain. Until this evidence is available, guidelines recommending standardized pain assessment must be clearly labelled as being based on principles or evidence from other fields of practice, and avoid implying that they are 'evidence based'.

Evidence for modulation of facial emotional processing bias during emotional expression decoding by serotonergic and noradrenergic antidepressants: an event-related potential (ERP) study

RATIONALE

Serotonergic (SSRI) and noradrenergic (NRI) antidepressants modulate biases in emotional processing such that perceptual bias is shifted away from negative and towards positive emotional material. However, the effects of serotonergic and noradrenergic modulation on the temporal course (occurring in milliseconds) of emotional processing, and in particular, the rapid physiological changes associated with the different stages of emotional processing, are unknown.

OBJECTIVE

The current study assessed the effects of acute serotonergic (i.e. with citalopram) and noradrenergic (i.e. with reboxetine) augmentation on event-related potential (ERP) measures associated with 'structural encoding' (N170) and emotion expression decoding (N250 and late positive potential [LPP]) for positive (happy) and negative (sad) facial stimuli relative to neutral facial stimuli.

MATERIALS AND METHODS

This study employed a double-blind, placebo-controlled, cross-over design in which 12 healthy male participants completed a facial expression recognition task tested under three acute conditions: (a) placebo, (b) citalopram (20 mg) and (c) reboxetine (4 mg).

RESULTS

Both citalopram and reboxetine had no effect on the N170 ERP component associated with structural encoding, but potentiated the N250 associated with happy (relative to neutral) emotional facial expression decoding. Both drugs had no valence effects on later ERP measures of emotion expression decoding (LPP).

CONCLUSIONS

Citalopram and reboxetine have selective effects on the temporal course of emotional processing with evidence to suggest specific effects on emotion expression decoding of positive (happy) emotional facial stimuli as evidenced by changes in the attention-modulated N250 but not structural encoding. These findings provide physiological evidence that antidepressants may shift perceptual biases in emotional processing away from negative and towards positive stimuli.

Two-week treatment with the selective serotonin reuptake inhibitor citalopram reduces contextual anxiety but not cued fear in healthy volunteers: a fear-potentiated startle study

Chronic treatment with selective serotonin reuptake inhibitors (SSRIs) alleviates both anxiety symptoms and associated physiologic disturbances in anxious patients. However, limited research considers the degree to which chronic SSRI treatment influences anxiety in healthy individuals. This study examined the effect of 2-week citalopram treatment on two threat responses: short- and long-duration-potentiated startle. Prior work suggests that these two responses provide neurally and functionally distinct models of fear and anxiety, respectively, in rodents. Healthy volunteers (n=53) received either placebo or citalopram (20 mg per day) for 2 weeks under double-blind conditions. They were each tested twice, before and after treatment. Participants were exposed to three conditions, including one in which predictable aversive shocks were signaled by a cue, a second in which unpredictable shocks were anticipated, and a third in which no shocks were administered. Aversive states were indexed by acoustic startle. Phasic fear-potentiated startle to the threat cue, as well as sustained startle potentiation to the experimental context in the predictable and unpredictable conditions, were investigated. Citalopram affected neither baseline startle nor short-duration fear-potentiated startle to discrete threat cues. However, citalopram reduced long-duration startle potentiation in the predictable conditions. These results are consistent with the hypothesis that short- and long-duration aversive states are mediated by distinct neural systems. They suggest that citalopram alleviates symptoms of anticipatory anxiety, not fear, by acting on mechanisms underlying long-duration aversive states.

Short-term serotonergic but not noradrenergic antidepressant administration reduces attentional vigilance to threat in healthy volunteers

Anxiety is associated with threat-related biases in information processing such as heightened attentional vigilance to potential threat. Such biases are an important focus of psychological treatments for anxiety disorders. Selective serotonin reuptake inhibitors (SSRIs) are effective in the treatment of a range of anxiety disorders. The aim of this study was to assess the effect of an SSRI on the processing of threat in healthy volunteers. A selective noradrenergic reuptake inhibitor (SNRI), which is not generally used in the treatment of anxiety, was used as a contrast to assess the specificity of SSRI effects on threat processing. Forty-two healthy volunteers were randomly assigned to 7 d double-blind intervention with the SSRI citalopram (20 mg/d), the SNRI reboxetine (8 mg/d), or placebo. On the final day, attentional and interpretative bias to threat was assessed using the attentional probe and the homograph primed lexical decision tasks. Citalopram reduced attentional vigilance towards fearful faces but did not affect the interpretation of ambiguous homographs as threatening. Reboxetine had no significant effect on either of these measures. Citalopram reduces attentional orienting to threatening stimuli, which is potentially relevant to its clinical use in the treatment of anxiety disorders. This finding supports a growing literature suggesting that an important mechanism through which pharmacological agents may exert their effects on mood is by reversing the cognitive biases that characterize the disorders that they treat. Future studies are needed to clarify the neural mechanisms through which these effects on threat processing are mediated.

The pharmacologic treatment of patients with generalized anxiety disorder: where are we now and where are we going?

Evidence-based guidelines for the pharmacologic management of patients with generalized anxiety disorder (GAD) recommend initial treatment with either a selective serotonin reuptake inhibitor (SSRI) or a serotonin-norepinephrine reuptake inhibitor (SNRI). However, response rates to initial treatment with an SSRI or SNRI can be disappointing, and it remains impossible to predict reliably which patients will respond positively or negatively to treatment. Due to the dearth of longitudinal studies of outcome in GAD and the relatively small number of placebo-controlled relapse prevention studies, the optimal duration of treatment after a satisfactory response to acute treatment is still uncertain. Furthermore, there have been few studies on the management of patients who do not respond to initial treatment. Also, there is a clear need for further randomized controlled trials of augmentation treatment in patients who do not respond to SSRI, SNRI, or other initial pharmacologic approaches. Future guidelines will be influenced by emerging data with both established and novel drug treatments, and through better identification of patient groups that are likely to respond preferentially to particular interventions.

Recent advances in understanding and treating social anxiety disorder

The common occurrence and high level of morbidity and burden associated with social anxiety disorder (SAD) are gaining widespread recognition. Interest in understanding and treating the disorder has also grown in response to large-scale investigations that have demonstrated high levels of efficacy with both pharmacologic and nonpharmacologic treatments. Such trials indicate that many patients with generalized SAD (roughly 40% to 60%) respond (eg, Clinical Global Impressions-Improvement rating 1 or 2) after an adequate treatment trial, despite having suffered with disabling symptoms for most of their adult lives. First-line therapy options include the selective serotonin reuptake inhibitors and the dual-acting serotonin-norepinephrine reuptake inhibitor venlafaxine. Second-line options consist of anticonvulsants (gabapentin, pregabalin, valproic acid) and benzodiazepines (clonazepam). Reversible and irreversible monoamine oxidase inhibitors (moclobemide and phenelzine, respectively), while effective, are not widely used. Nonpharmacologic approaches, such as cognitive-behavioral therapy (CBT), are also effective for SAD. Newer treatment strategies such as levetiracetam, atypical antipsychotics, or D-cycloserine in combination with CBT appear promising but require further investigation. Finding a well-tolerated, safe, and effective treatment for each individual patient is crucial as most will require ongoing treatment in order to maintain benefits, prevent SAD relapse, and to experience optimal outcomes in the long term.

Risk for depression and neural responses to fearful facial expressions of emotion

BACKGROUND

Depression is associated with neural abnormalities in emotional processing.

AIMS

This study explored whether these abnormalities underlie risk for depression.

METHOD

We compared the neural responses of volunteers who were at high and low-risk for the development of depression (by virtue of high and low neuroticism scores; high-N group and low-N group respectively) during the presentation of fearful and happy faces using functional magnetic resonance imaging (fMRI).

RESULTS

The high-N group demonstrated linear increases in response in the right fusiform gyrus and left middle temporal gyrus to expressions of increasing fear, whereas the low-N group demonstrated the opposite effect. The high-N group also displayed greater responses in the right amygdala, cerebellum, left middle frontal and bilateral parietal gyri to medium levels of fearful v. happy expressions.

CONCLUSIONS

Risk for depression is associated with enhanced neural responses to fearful facial expressions similar to those observed in acute depression.

Facial emotion recognition impairment in chronic temporal lobe epilepsy

PURPOSE

To evaluate facial emotion recognition (FER) in a cohort of 176 patients with chronic temporal lobe epilepsy (TLE).

METHODS

FER was tested by matching facial expressions with the verbal labels for the following basic emotions: happiness, sadness, fear, disgust, and anger. Emotion recognition performances were analyzed in medial (n = 140) and lateral (n = 36) TLE groups. Fifty healthy subjects served as controls. The clinical and neuroradiologic variables potentially affecting the ability to recognize facial expressions were taken into account.

RESULTS

The medial TLE (MTLE) group showed impaired FER (86% correct recognition) compared to both the lateral TLE patients (FER = 93.5%) and the controls (FER = 96.4%), with 42% of MTLE patients recording rates of FER that were lower [by at least 2 standard deviations (SDs)] than the control mean. The MTLE group was impaired compared to the healthy controls in the recognition of all basic facial expressions except happiness. The patients with bilateral MTLE were the most severely impaired, followed by the right and then the left MTLE patients. FER was not affected by type of lesion, number of antiepileptic drugs (AEDs), aura semiology, or gender. Conversely, the early onset of seizures/epilepsy was related to FER deficits. These deficits were already established in young adulthood, with no evidence of progression in older MTLE patients.

CONCLUSION

These results on a large cohort of TLE patients demonstrate that emotion recognition deficits are common in MTLE patients and widespread across negative emotions. We confirm that early onset seizures with right or bilateral medial temporal dysfunction lead to severe deficits in recognizing facial expressions of emotions.

Improving the prediction of treatment response in depression: integration of clinical, cognitive, psychophysiological, neuroimaging, and genetic measures

Antidepressants are important in the treatment of depression, and selective serotonin reuptake inhibitors are first-line pharmacologic options. However, only 50% to 70% of patients respond to first treatment and <40% remit. Since depression is associated with substantial morbidity, mortality, and family burden, it is unfortunate and demanding on health resources that patients must remain on their prescribed medications for at least 4 weeks without knowing whether the particular antidepressant will be effective. Studies have suggested a number of predictors of treatment response, including clinical, psychophysiological, neuroimaging, and genetics, each with varying degrees of success and nearly all with poor prognostic sensitivity and specificity. Studies are yet to be conducted that use multiple measures from these different domains to determine whether sensitivity and specificity can be improved to predict individual treatment response. It is proposed that a focus on standardized testing methodologies across multiple testing modalities and their integration will be crucial for translation of research findings into clinical practice.

Emotional face processing in women with high and low levels of eating disorder related symptoms

OBJECTIVES

Emotional processing has rarely been investigated in those "at risk" of developing an eating disorder. This study investigated the processing of six basic emotions depicted on faces in an "at risk" group, compared to a control group.

DESIGN

Participants were women with high (N=29) and low (N=23) levels of eating disorder symptoms who were not taking psychotropic medication. A well characterised computerised task (Facial Expression Emotion Task) was administered to all participants.

RESULTS

Women with high levels of eating disorder symptoms, compared to those with low levels, were less accurate at recognising happy and neutral faces, but showed no differences in their accuracy at recognising other emotions. They also showed a trend to be less good at discriminating anger, but better at discriminating surprise from other emotions. Depressive and anxious symptoms did not provide a complete explanation for the findings.

CONCLUSIONS

The findings support the inclusion of emotional processing in models of eating disorders, and suggest that it may have a role in their development. Emotional processing warrants further investigation particularly in those "at risk" but also in those with eating disorders.

Serotonergic modulation of face-emotion recognition

Facial expressions of basic emotions have been widely used to investigate the neural substrates of emotion processing, but little is known about the exact meaning of subjective changes provoked by perceiving facial expressions. Our assumption was that fearful faces would be related to the processing of potential threats, whereas angry faces would be related to the processing of proximal threats. Experimental studies have suggested that serotonin modulates the brain processes underlying defensive responses to environmental threats, facilitating risk assessment behavior elicited by potential threats and inhibiting fight or flight responses to proximal threats. In order to test these predictions about the relationship between fearful and angry faces and defensive behaviors, we carried out a review of the literature about the effects of pharmacological probes that affect 5-HT-mediated neurotransmission on the perception of emotional faces. The hypothesis that angry faces would be processed as a proximal threat and that, as a consequence, their recognition would be impaired by an increase in 5-HT function was not supported by the results reviewed. In contrast, most of the studies that evaluated the behavioral effects of serotonin challenges showed that increased 5-HT neurotransmission facilitates the recognition of fearful faces, whereas its decrease impairs the same performance. These results agree with the hypothesis that fearful faces are processed as potential threats and that 5-HT enhances this brain processing.

Dissociable effects of acute antidepressant drug administration on subjective and emotional processing measures in healthy volunteers

BACKGROUND

We have previously shown that single doses of serotonin-selective and noradrenaline-selective antidepressant agents produce positive biases in measures of emotional processing in healthy volunteers. The aim of the present study was to confirm and extend this finding by studying the effects of a single dose of the selective serotonin and noradrenaline re-uptake inhibitor, duloxetine.

MATERIALS AND METHODS

Healthy volunteers were randomly allocated to double-blind administration of either duloxetine 60 mg orally or placebo. Participants then completed a battery of emotional-processing tasks measuring facial expression recognition, emotional memory and emotion-potentiated startle. Subjective state was measured using visual analogue scales throughout the test period.

RESULTS

Duloxetine enhanced the recognition of both disgusted and happy facial expressions and increased memory intrusions for positive personality characteristics in the free recall test. There were no significant effects on startle responses. However, duloxetine was not well tolerated and was associated with a high level of negative subjective effects.

CONCLUSIONS

Despite the induction of negative subjective effects after duloxetine administration, some positive effects on emotional processing were seen in line with acute administration of serotonin-selective and noradrenaline-selective antidepressant agents. These results confirm the induction of fast changes in emotional processing in healthy volunteer groups and suggest a mechanism by which antidepressants may act in depression. Further studies are required to assess whether positive effects on emotional processing are more selective at a lower dose of duloxetine.

Residual cognitive impairments in remitted depressed patients

Depressive disorders are associated with various cognitive impairments. Studies on whether or not these impairments persist into the euthymic phase have shown conflicting results, due to differences in test versions and in study samples. In this paper, we aimed to compare the cognitive performance of remitted depressed patients with that of age- and gender-matched healthy volunteers across a wide range of cognitive domains. In two studies, we found few differences on neutral as well as emotional information processing tests. The findings indicate that remitted depressed patients who use antidepressant medication still show an increased recognition of facial expression of fear compared to healthy controls. Patients also performed worse on a test of recognition of abstract visual information from long-term memory. No other residual cognitive impairments were found. These results indicate that most of the cognitive impairments associated with depression resolve with recovery through medication, even when recovery is incomplete. Considering the finding that remitted depressed patients have higher levels of cognitive reactivity, future studies may investigate the possibility that these cognitive impairments have not resolved but have become latent, and may therefore easily be triggered by small changes in mood state.

The effects of experimentally lowered serotonin function on emotional information processing and memory in remitted depressed patients

It has been well documented that acute tryptophan depletion (ATD) induces symptoms in remitted depressed patients treated with an SSRI. ATD also has effects on cognition, both in patients and in healthy samples. The exact nature of ATD-induced cognitive changes in depression remains unclear. It is also unclear whether cognitive effects can be induced through partial ('low-dose') depletion. The aim of this study is to investigate the differential effects of low-dose and high-dose ATD on emotional information processing and mood in remitted depressed patients. Eighteen remitted depressed patients received high-dose and low-dose ATD in a randomized, double-blind, within-subjects crossover design. Mood was assessed before and after administration of the depletion drink. Five hours after administration, patients conducted tests measuring neutral and emotional information processing. High-dose ATD increased depressive symptoms and induced a temporary depressive 'relapse' in half of the patients. High-dose ATD also decreased the recognition of fear and impaired learning and memory retrieval. The impaired learning occurred only in mood-responders. Low-dose ATD had no effects on mood but speeded the recognition of facial expressions of disgust. Accurate recognition of sad faces at baseline was associated with mood response to ATD. High-dose ATD leads to changes in memory and in the recognition of negative facial expressions in SSRI-treated remitted depressed patients. The effect of low-dose ATD on mood and cognition seems to be quite limited. Emotional information processing at baseline predicts mood-response to ATD.

Serotonin, inhibition, and negative mood

Pavlovian predictions of future aversive outcomes lead to behavioral inhibition, suppression, and withdrawal. There is considerable evidence for the involvement of serotonin in both the learning of these predictions and the inhibitory consequences that ensue, although less for a causal relationship between the two. In the context of a highly simplified model of chains of affectively charged thoughts, we interpret the combined effects of serotonin in terms of pruning a tree of possible decisions, (i.e., eliminating those choices that have low or negative expected outcomes). We show how a drop in behavioral inhibition, putatively resulting from an experimentally or psychiatrically influenced drop in serotonin, could result in unexpectedly large negative prediction errors and a significant aversive shift in reinforcement statistics. We suggest an interpretation of this finding that helps dissolve the apparent contradiction between the fact that inhibition of serotonin reuptake is the first-line treatment of depression, although serotonin itself is most strongly linked with aversive rather than appetitive outcomes and predictions.

Serotonin is an evolutionarily ancient neuromodulator probably best known for its role in psychiatric disorders. However, that role has long appeared contradictory to its role in normal function, and indeed its various roles in normal affective behaviors have been hard to reconcile. Here, we model two predominant functions of normal serotonin function in a highly simplified reinforcement learning model and show how these may explain some of its complex roles in depression and anxiety.

Antidepressive therapy with escitalopram improves mood, cognitive symptoms, and identity memory for angry faces in elderly depressed patients

Depression is a common disorder in the elderly handicapping patients with affective and cognitive symptoms. Because of their good tolerability relative to the older tricyclic compounds, selective serotonin reuptake inhibitors (SSRIs) are increasingly used for the treatment of depression in the elderly. Little is known about their effects on cognition in elderly patients. In the present 4-wk, single-centre, randomized, open-label trial we investigated the antidepressive effects of escitalopram, an SSRI, in 18 elderly depressed patients [mean age (+/-s.e.m.) 76.2+/-1.8 yr] compared to 22 healthy age-matched controls (mean age 76.9+/-1.8 yr). Affective and cognitive symptoms were assessed using the Geriatric Depression Scale (GDS), Mini-Mental State Examination (MMSE), and a face portrait recognition test to assess memory for happy and angry faces. Depressed patients prior to treatment had markedly reduced memory performance. Treatment with escitalopram improved affective and cognitive symptoms significantly. Furthermore, escitalopram treatment improved memory for negative facial stimuli. Control subjects confirmed the well- established memory bias favouring recognition of identities acquired with happy expressions. Importantly, this bias was absent in depressed patients prior to, but also after treatment. In conclusion, escitalopram, even after a relatively short treatment period, was effective in treating depression in the elderly and may help improve cognitive performance for social stimuli.

Increased serotonin and dopamine transporter binding in psychotropic medication-naive patients with generalized social anxiety disorder shown by 123I-beta-(4-iodophenyl)-tropane SPECT

There is circumstantial evidence for the involvement of serotonergic and dopaminergic systems in the pathophysiology of social anxiety disorder. In the present study, using SPECT imaging we examined the (123)I-beta-(4-iodophenyl)-tropane binding potential for the serotonin and dopamine transporters in patients with a generalized social anxiety disorder and in age- and sex-matched healthy controls.

METHODS

Twelve psychotropic medication-naïve patients with social anxiety disorder, generalized type (5 women and 7 men) and 12 sex- and age-matched healthy controls were studied. Volumes of interest were constructed on MRI-coregistered SPECT scans. Binding ratios were compared using the Mann-Whitney U test. Possible correlations between binding patterns and symptomatology were assessed using the Spearman rank correlation coefficient.

RESULTS

Significantly higher binding potentials were found for the serotonin in the left and right thalamus of patients. Patients had also a significantly higher binding potential for the dopamine transporter in the striatum.

CONCLUSION

The present study provided direct evidence for abnormalities in both the dopaminergic and the serotonergic systems in patients with generalized social anxiety disorder.

An examination of acute changes in serotonergic neurotransmission using the loudness dependence measure of auditory cortex evoked activity: effects of citalopram, escitalopram and sertraline

OBJECTIVE

The underlying effect of serotonergic neurotransmission has been implicated in several psychiatric disorders. The inability to routinely and non-invasively determine the integrity of the serotonergic system in vivo has limited our understanding of disorders with a putative serotonergic abnormality. The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as a reliable measure of central serotonin function in humans. While animal studies suggest that the LDAEP is sensitive to changes in central serotonin neurotransmission, evidence in humans has been indirect and inconsistent. The aim of this study was to assess the sensitivity of the LDAEP to acute augmentation in central serotonergic neurotransmission in humans.

METHODS

The study used a double-blind, placebo-controlled cross-over design, in which healthy subjects were tested under four acute treatment conditions, with pharmacologically equivalent single doses of placebo, escitalopram (10 mg), citalopram (20 mg) and sertraline (50 mg) to examine the direct effect of acute enhancement of synaptic serotonin on the LDAEP. Furthermore, the outcome of the serotonergic modulatory effects on the LDAEP was also examined using two methods (dipole source analysis (DSA) vs. scalp analysis).

RESULTS

Escitalopram, citalopram and sertraline had no effects on the LDAEP and were independent of the analysis method used.

CONCLUSION

These findings question the sensitivity of the LDAEP to acute changes in serotonin neurotransmission and its validity as a reliable measure of central serotonin function in humans.