Administration Of Selective Serotonin Reuptake Inhibitors Research Articles

Kleptomania: Beyond serotonin

Sir, Kleptomania has been described as an inability to refrain from the urge to steal things for reasons other than personal use or financial gain. Decades of research show that both dopamine and serotonin are the primary neurotransmitters involved in the pathogenesis and management of kleptomania, respectively. Selective serotonin reuptake inhibitors (SSRIs) have been used as first-line agents for treating kleptomania. On the contrary, cases of kleptomania had been paradoxically induced in three adults who were started on SSRIs for depression.[1] A recent Indian paper also reports a similar manifestation while on fluvoxamine treatment for obsessive compulsive disorder.[2] Restlessness and impulsivity have been recognized as symptoms of behavioral activation during initiation of treatment with SSRIs. Emergence of kleptomania post SSRI treatment may be partly explained by the same phenomenon in which there could be effective depletion of synaptic serotonin post acute administration of SSRIs through serotonin-mediated action on its auto-receptor. While the role of serotonin is murky, the role of dopamine is increasingly getting clearer especially in neurological disorders. Kleptomania is seen as an emergent side effect of the use of dopamine agonists in Parkinson's disease (PD). Other impulse control disorders (ICDs) like pathological gambling, compulsive shopping, compulsive eating and hypersexuality have also been reported with the use of dopamine agonists. This phenomenon is explained by the overdose theory.[3] In PD, ventral striatal dopamine is preserved relative to dorsal striatal activity; thus, dopaminergic treatment titrated to alleviate motor dorsal striatal deficiencies may result in an “over-dosing” in ventral cortico-striatal cognitive and limbic pathways. And as such there is preliminary evidence for the benefit of atypical antipsychotics for treating impulse regulation disorders.[4] At the same time, serotonergic and dopaminergic systems are not mutually exclusive. Could an alteration in dopamine levels post SSRI initiation explain the emergence of kleptomania in rare cases? SSRIs are known to sensitize dopamine (D2) receptors.[5] On the other hand, could the apparent effectiveness of SSRIs in kleptomania be because of their dopaminergic modulation rather than their primary effect on the serotonergic system? Kleptomania shares certain distinct features with substance use disorders, unlike other impulse control disorders like intermittent explosive disorder. This possible association between the two has resulted in naltrexone being tried as a treatment strategy for kleptomania with favorable results.[6] Further supportive evidence can be obtained from the rare finding of new onset alcohol dependence linked to treatment with SSRI.[7] This intriguing phenomenon can be considered similar to the earlier mentioned reports of emergence of kleptomania after taking SSRIs. Probably the mechanism, although still speculative, may be similar in both phenomena. So along with the erstwhile serotonin and dopamine, treatment of kleptomania is further complicated with the involvement of opioid and glutamatergic system.[8] Kleptomania is often been found comorbid with other psychiatric disorders including depression, addiction and personality disorders. Various structural brain lesions have been associated with kleptomania including head trauma.[9] Decreased white matter microstructural integrity in the inferior frontal brain region has also been identified in patients with kleptomania.[10] Functional anatomy of impulse control disorders including kleptomania has recently been reviewed.[11] While medications that affect the serotonergic system have been most widely studied for the treatment of kleptomania, their clinical effects have been modest or inconsistent or even paradoxical. Medications that affect dopaminergic neurotransmission have received less research attention. Kleptomania is the final common manifestation of various underlying pathogenic mechanisms which calls for rationalization of treatment based on co-morbid symptoms and personality traits rather than blanket use of one agent. Extension of this suggestion to other impulse control disorders requires renewed research interest and further elaboration. Developments in neurobiology and pharmaco-genetics, coupled with newer pharmacological models involving the opioid and glutamate systems will surely further our understanding of the pathophysiology and pharmacotherapy of kleptomania.

Acute escitalopram but not contextual conditioning exerts a stronger "anxiogenic" effect in rats with high baseline "anxiety" in the acoustic startle paradigm.

Acute administration of selective serotonin reuptake inhibitors (SSRIs) may enhance anxiety in humans, those with anxiety disorders being more susceptible than others. Fear-conditioned or unconditioned acoustic startle and freezing are common measures of fear and/or "anxiety" in rodents that may be used to study this effect of SSRIs preclinically. Our aim was to shed further light on the effect of acute administration of an SSRI, escitalopram (10mg/kg), on startle and freezing in the absence or presence of prior contextual conditioning. Repeated testing also enabled us to evaluate (i) if there are stable inter-animal variations with respect to these parameters in a batch of outbred Wistar rats, (ii) the possible relationship between the two and (iii) if baseline behaviour predicts the response to escitalopram. Inter-animal test-retest correlations were found for both startle and freezing at baseline, and the two parameters also correlated with each other. Both escitalopram and contextual conditioning increased freezing and startle but without exerting any synergistic effect. While animals displaying high startle at baseline showed higher susceptibility to respond to escitalopram, the effect of conditioning was more pronounced in those with low baseline startle. The results support the usefulness of both conditioned and non-conditioned startle and freezing to capture an "anxiogenic" influence of SSRIs. Also, they suggest that baseline non-conditioned startle may predict this response in a manner reflecting the clinical situation in the sense that subjects with high baseline "anxiety" are particularly prone to respond with enhanced "anxiety" following acute SSRI administration.

Prophylactic antidepressant treatment of interferon-induced depression in chronic hepatitis C: a systematic review and meta-analysis.

To assess the utility of prophylactic administration of antidepressants in preventing a major depressive episode during antiviral treatment for chronic hepatitis C. A computerized literature search was conducted in MEDLINE, PsycINFO, EMBASE, the Cochrane Library, and ClinicalTrials.gov to locate articles published in any language from the earliest available online year until October 2012, using the following phrase and Boolean logic algorithm: "hepatitis and c and (interferon-alpha OR peginterferon OR (pegylated and interferon)) and (depression OR mood) and (prevention OR prophylactic OR prophylaxis OR antidepressant)." Double-blind, randomized, placebo-controlled trials using antidepressants prophylactically before starting antiviral therapy for chronic hepatitis C were included. At baseline, none of the patients in the trials presented depression (DSM-IV-TR criteria). Using keywords and cross-referenced bibliographies, 144 studies were identified and examined in depth. 137 articles were rejected because inclusion criteria were not met. Finally, 7 studies were included. Data were extracted independently by 2 investigators. The primary outcome measure was the onset of a major depressive episode during the antiviral treatment. Depressive symptoms, other side effects, and sustained virologic response were also examined. A full review and meta-analysis were performed. Odds ratios (ORs), mean differences, and estimated numbers needed to treat (NNTs) with 95% confidence intervals (CIs) were calculated. 591 patients were randomly assigned to antiviral treatment and another intervention: escitalopram (n = 197), paroxetine (n = 42), citalopram (n = 53), or placebo (n = 299). Selective serotonin reuptake inhibitors (SSRIs), as a group, reduced the incidence of a major depressive episode during antiviral treatment (OR = 0.53; 95% CI, 0.33 to 0.84). The NNT was 12 (95% CI, 7.0 to 37.9). SSRIs reduced depressive symptoms at 24 weeks of treatment (mean difference -2.18; 95% CI, -4.25 to -0.10). With regard to side effects, only dizziness was associated with administration of antidepressants (OR = 2.65; 95% CI, 1.46 to 4.80). There were no differences in sustained virologic response (OR = 1.22; 95% CI, 0.58 to 2.57). Administration of SSRIs before starting antiviral treatment reduces the incidence of interferon-induced depression, with a relatively moderate prophylactic impact and good tolerability.

Effects of Neonatal Fluvoxamine Administration on the Physical Development and Activity of the Serotoninergic System in White Rats

Selective serotonin reuptake inhibitors (SSRIs), including fluvoxamine, are widely used to treat depressive disorders in pregnant women. These antidepressants effectively penetrate through the placental barrier, affecting the fetus during the critical phase of neurodevelopment. Some clinical studies have linked prenatal exposure to SSRIs with increased neonatal mortality, premature birth, decreased fetal growth and delay in psychomotor development. However, the effects of prenatal exposure to SSRIs remain unknown. The administration of SSRIs in rodents during the first postnatal weeks is considered as an model for studying the effects of prenatal SSRIs exposure in human. The aim of this work was to study the acute effects of chronic fluvoxamine (FA) administration in white rat pups. The study was carried out in male and female rat pups treated with FA (10 mg/kg/day, intraperitoneally) from postnatal days 1 to 14. The lethality level, body weight, age of eye opening, and motor reflex maturation were recorded. The contents of biogenic amines and their metabolites in different brain structures were also determined. It was shown that neonatal FA administration led to increased lethality level, reduced body weight, and delayed maturation of motor reflexes. Furthermore, increased noradrenalin level in hypothalamus, serotonin level in hippocampus and serotonin metabolite 5-HIAA level in frontal cortex, hypothalamus, hippocampus, and striatum were observed in drug-treated animals compared to the control group. We can conclude that the altered activity of the serotoninergic system induced by fluvoxamine administration at early developmental stages leads to a delay in physical and motor development.

Serum Prolactin and Macroprolactin Levels among Outpatients with Major Depressive Disorder Following the Administration of Selective Serotonin-Reuptake Inhibitors: A Cross-Sectional Pilot Study

Clinical trials evaluating the rate of short-term selective serotonin-reuptake inhibitor (SSRI)-induced hyperprolactinemia have produced conflicting results. Thus, the aim of this study was to clarify whether SSRI therapy can induce hyperprolactinemia and macroprolactinemia. Fifty-five patients with major depressive disorder (MDD) were enrolled in this study. Serum prolactin and macroprolactin levels were measured at a single time point (i.e., in a cross-sectional design). All patients had received SSRI monotherapy (escitalopram, paroxetine, or sertraline) for a mean of 14.75 months. Their mean prolactin level was 15.26 ng/ml. The prevalence of patients with hyperprolactinemia was 10.9% for 6/55, while that of patients with macroprolactinemia was 3.6% for 2/55. The mean prolactin levels were 51.36 and 10.84 ng/ml among those with hyperprolactinemia and a normal prolactin level, respectively. The prolactin level and prevalence of hyperprolactinemia did not differ significantly within each SSRI group. Correlation analysis revealed that there was no correlation between the dosage of each SSRI and prolactin level. These findings suggest that SSRI therapy can induce hyperprolactinemia in patients with MDD. Clinicians should measure and monitor serum prolactin levels, even when both SSRIs and antipsychotics are administered.

Acute hemodynamic effects of a selective serotonin reuptake inhibitor in postural tachycardia syndrome: A randomized, crossover trial

Selective serotonin reuptake inhibitors (SSRIs) are often prescribed in patients with postural tachycardia syndrome (POTS), and act at synaptic terminals to increase monoamine neurotransmitters. We hypothesized that they act to increase blood pressure and attenuate reflex tachycardia, thereby improving symptoms. Acute hemodynamic profiles after SSRI administration in POTS patients have not previously been reported. Patients with POTS (n=39; F=37, 39 ±9 years) underwent a randomized crossover trial with sertraline 50mg and placebo. Heart rate, systolic, diastolic, and mean blood pressure were measured with the patient seated and standing for 10 min prior to drug or placebo administration, and then hourly for 4 h. The primary endpoint was standing heart rate at 4 h. At 4 h, standing heart rate and systolic blood pressure were not significantly different between sertraline and placebo. Seated systolic (106±12 mmHg vs. 101±8 mmHg; p=0.041), diastolic (72±8 mmHg vs. 69±8 mmHg; p=0.022), and mean blood pressure (86±9 mmHg vs. 81±9 mmHg; p=0.007) were significantly higher after sertraline administration than placebo. At 4 h, symptoms were worse with sertraline than placebo. Sertraline had a modest pressor effect in POTS patients, but this did not translate into a reduced heart rate or improved symptoms.

Perioperative Use of Selective Serotonin Reuptake Inhibitors and Risks for Adverse Outcomes of Surgery

Single-site studies have described an association between use of selective serotonin reuptake inhibitors (SSRIs) and adverse outcomes of surgery. Multicenter studies including a broad range of surgical procedures that explore rare outcomes, such as bleeding and mortality, and that account for indications for administration of SSRIs are needed. To determine whether perioperative use of SSRIs is associated with adverse outcomes of surgery in a national sample of patients. Retrospective study of patients 18 years or older who underwent major surgery from January 1, 2006, through December 31, 2008, at 375 US hospitals. We used multivariable hierarchical models to estimate associations between SSRI use and our outcomes. Pharmacy data were used to determine whether a patient received an SSRI in the perioperative period. Three hundred seventy-five US hospitals. Five hundred thirty thousand four hundred sixteen patients 18 years or older. Perioperative use of SSRIs. In-hospital mortality, length of stay, readmission at 30 days, bleeding events, transfusions, and incidence of ventricular arrhythmias. Patients receiving SSRIs were more likely to have obesity, chronic pulmonary disease, or hypothyroidism (P < .001 for each) and more likely to have depression (41.0% vs 6.2%, P < .001). After adjustment, patients receiving SSRIs had higher odds of in-hospital mortality (adjusted odds ratio, 1.20 [95% CI, 1.07-1.36]), bleeding (1.09 [1.04-1.15]), and readmission at 30 days (1.22 [1.18-1.26]). Similar results were observed in propensity-matched analyses, although the risk of inpatient mortality was attenuated among patients with depression. Sensitivity analyses suggest that, to invalidate our results, an unmeasured covariate would have to have higher prevalence and be more strongly associated with mortality than any covariate included in our models. Receiving SSRIs in the perioperative period is associated with a higher risk for adverse events. Determining whether patient factors or SSRIs themselves are responsible for elevated risks requires prospective study.

Antidepressant treatment outcome depends on the quality of the living environment: a pre-clinical investigation in mice.

Antidepressants represent the standard treatment for major depression. However, their efficacy is variable and incomplete. A growing number of studies suggest that the environment plays a major role in determining the efficacy of these drugs, specifically of selective serotonin reuptake inhibitors (SSRI). A recent hypothesis posits that the increase in serotonin levels induced by SSRI may not affect mood per se, but enhances neural plasticity and, consequently, renders the individual more susceptible to the influence of the environment. Thus, SSRI administration in a favorable environment would lead to a reduction of symptoms, while in a stressful environment might lead to a worse prognosis. To test this hypothesis, we treated C57BL/6 adult male mice with chronic fluoxetine while exposing them to either (i) an enriched environment, after exposure to a chronic stress period aimed at inducing a depression-like phenotype, or (ii) a stressful environment. Anhedonia, brain BDNF and circulating corticosterone levels, considered endophenotypes of depression, were investigated. Mice treated with fluoxetine in an enriched condition improved their depression-like phenotype compared to controls, displaying higher saccharin preference, higher brain BDNF levels and reduced corticosterone levels. By contrast, when chronic fluoxetine administration occurred in a stressful condition, mice showed a more distinct worsening of the depression-like profile, displaying a faster decrease of saccharin preference, lower brain BDNF levels and increased corticosterone levels. Our findings suggest that the effect of SSRI on depression-like phenotypes in mice is not determined by the drug per se but is induced by the drug and driven by the environment. These findings may be helpful to explain variable effects of SSRI found in clinical practice and to device strategies aimed at enhancing their efficacy by means of controlling environmental conditions.

Paradoxical effects of short-term antidepressant treatment in fMRI emotional processing models in volunteers with high neuroticism

Short-term antidepressant administration has been reported to decrease amygdala response to threat in healthy volunteers and depressed patients. Neuroticism (N) is a risk factor for depression but has also been associated with slow or incomplete remission with antidepressant drug treatment. Our aim was to investigate early selective serotonin reuptake inhibitor (SSRI) administration neural effects on implicit processing of fearful facial expressions in volunteers with high levels of N. Highly neurotic subjects received 20 mg/day citalopram versus placebo for 7 days in a double-blind, between-groups design. On the last day haemoperfusion and functional magnetic resonance imaging (fMRI) data during a gender discrimination task with fearful and happy faces were acquired. A control group of non-neurotic volunteers was also tested. High-N volunteers had reduced responses to threatening facial expressions across key neural circuits compared to low-N volunteers. SSRI treatment was found to elevate resting perfusion in the right amygdala, increase bilateral amygdalae activation to positive and negative facial expressions and increase activation to fearful versus happy facial expressions in occipital, parietal, temporal and prefrontal cortical areas. These results suggest that 7 days of SSRI administration can increase neural markers of fear reactivity in subjects at the high end of the N dimension and may be related to early increases in anxiety and agitation seen early in treatment. Such processes may be involved in the later therapeutic effects through decreased avoidance and increased learning about social 'threat' cues.

‘It's the way that you look at it’—a cognitive neuropsychological account of SSRI action in depression

The fact that selective serotonin reuptake inhibitors (SSRIs) have antidepressant effects in some patients supports the notion that serotonin plays a role in the mode of action of antidepressant drugs. However, neither the way in which serotonin may alleviate depressed mood nor the reason why several weeks needs to elapse before the full antidepressant effect of treatment is expressed is known. Here, we propose a neuropsychological theory of SSRI antidepressant action based on the ability of SSRIs to produce positive biases in the processing of emotional information. Both behavioural and neuroimaging studies show that SSRI administration produces positive biases in attention, appraisal and memory from the earliest stages of treatment, well before the time that clinical improvement in mood becomes apparent. We suggest that the delay in the clinical effect of SSRIs can be explained by the time needed for this positive bias in implicit emotional processing to become apparent at a subjective, conscious level. This process is likely to involve the re-learning of emotional associations in a new, more positive emotional environment. This suggests intriguing links between the effect of SSRIs to promote synaptic plasticity and neurogenesis, and their ability to remediate negative emotional biases in depressed patients.

Strategy for treating selective serotonin reuptake inhibitor-resistant social anxiety disorder in the clinical setting: a randomised controlled trial protocol of cognitive behavioural therapy in combination with conventional treatment

IntroductionPharmacotherapy and cognitive behavioural therapy (CBT) are consistently effective as first-line treatments for social anxiety disorders (SADs). Nevertheless, pharmacotherapy is often the first choice in clinical practice. In many countries,...

Anti-emetic Effect of Mosapride Citrate Hydrate, a 5-HT4 Receptor Agonist, on Selective Serotonin Reuptake Inhibitors (SSRIs)-Induced Emesis in Experimental Animals

Although selective serotonin reuptake inhibitors (SSRIs) are widely used to treat depression, they frequently cause gastrointestinal adverse effects, such as nausea and emesis. In the present study, we investigated the anti-emetic effect of mosapride, a 5-HT4 receptor agonist, on SSRIs-induced emesis in Suncus murinus and dogs. We also examined the effect of mosapride on SSRIs-induced delay in gastric emptying and increase in gastric vagal afferent activity in rats. Oral administration of paroxetine, but not its subcutaneous administration, dose-dependently caused emesis in both animals. Mosapride inhibited paroxetine-induced emesis in Suncus murinus and dogs with ID50 values of 7.9 and 1.1 mg/kg, respectively. The anti-emetic effect of mosapride was partially inhibited by SB207266, a selective 5-HT4 antagonist. Intragastric administration of paroxetine increased gastric vagal afferent discharge in anesthetized rats. Mosapride failed to suppress this increase. On the other hands, mosapride improved the delay in gastric emptying caused by paroxetine in rats. We have shown in this study that oral administration of SSRIs causes emesis and activates gastric vagal afferent activity in experimental animals and that mosapride inhibits SSRIs-induced emesis, probably via improvement of SSRIs-induced delay in gastric emptying. These findings highlight the promising potential of mosapride as an anti-emetic agent.

Pharmacological approaches to the treatment of complicated grief: rationale and a brief review of the literature

Complicated grief (CG) is a common and often under-acknowledged cause of profound impairment experienced after the loss of a loved one. Although both clinical and basic research suggests that pharmacological agents might be of use in the treatment of CG, research on pharmacological approaches to this condition is still scarce. Three open-label trials and one randomized trial on bereavement-related depression suggest that tricyclic antidepressants may be effective, although they may be more efficacious for depressive symptoms than for grief-specific symptoms. Four open-label trials (total number of participants, 50) of selective serotonin reuptake inhibitors (SSRIs) have yielded results, providing very preliminary support that they might be effective in the treatment of CG, both as a standalone treatment and in conjunction with psychotherapeutic interventions. These more recent studies have shown an effect on both depression and grief-specific scales. Furthermore, therapeutic interventions for CG may be more effective in conjunction with SSRI administration. Given the small number of pharmacological studies to date, there is a need for randomized trials to test the potential efficacy of pharmacological agents in the treatment of CG.

Dopamine transporter binding in social anxiety disorder: the effect of treatment with escitalopram

Social anxiety disorder (SAD) is characterised by fear of social or performance situations where the individual is exposed to unfamiliar people or to possible scrutiny by others. The literature on dopamine ligands and dopamine genotypes in SAD is however inconsistent. In this study we measured the effects of SSRI pharmacotherapy on dopamine transporter (DAT) binding in patients with SAD, also addressing variability in DAT genotype. Adult subjects meeting DSM-IV criteria for generalised SAD were studied before and after 12 weeks of pharmacotherapy with the selective serotonin reuptake inhibitor (SSRI) escitalopram. DAT single photon emission computed tomography (SPECT) using (123)I-FP-CIT was performed at baseline, and repeated at 12 weeks. Striatal DAT binding was analysed for changes following therapy, and for correlations with clinical efficacy, in the whole group as well as for a subgroup with the A10/A10 DAT genotype. The study included 14 subjects (9 male, 5 female) with a mean (SD) age of 41 (±13) years. The subjects' Liebowitz Social Anxiety Scale (LSAS) score was significantly decreased following pharmacotherapy. In the combined group the left caudate and left putamen showed clusters of increased DAT binding after therapy. The left caudate changes were also observed in the subgroup of 9 A10/A10 homozygotes. However no correlation was found between improved symptoms and DAT binding. The changes found in DAT binding in the caudate and putamen may be due to serotonergic activation of dopamine function by SSRI therapy. This is consistent with previous work indicating decreased DAT binding in SAD, and increased DAT binding after SSRI administration.

Use of selective serotonin reuptake inhibitors and risk of fracture: A systematic review and meta-analysis

Previous studies have reported inconsistent findings regarding the association between the use of selective serotonin reuptake inhibitors (SSRIs) and the risk of fracture. We identified relevant studies by searching three electronic databases (MEDLINE, EMBASE, and the Cochrane Library) from their inception to October 20, 2010. Two evaluators independently extracted data. Because of heterogeneity, we used random-effects meta-analysis to obtain pooled estimates of effect. We identified 12 studies: seven case-control studies and five cohort studies. A meta-analysis of these 12 observational studies showed that the overall risk of fracture was higher among people using SSRIs (adjusted odds ratio [OR] = 1.69, 95% confidence interval [CI] 1.51-1.90, I(2 ) = 89.9%). Subgroup analysis by adjusted number of key risk factors for osteoporotic fracture showed a greater increased fracture risk in those adjusted for fewer than four variables (adjusted OR = 1.83, 95% CI 1.57-2.13, I(2) = 88.0%) than those adjusted for four or more variables (adjusted OR = 1.38, 95% CI 1.27-1.49, I(2) = 46.1%). The pooled ORs anatomical site of fracture in the hip/femur, spine, and wrist/forearm were 2.06 (95% CI 1.84-2.30, I(2 ) = 62.3%), 1.34 (95% CI 1.13-1.59, I(2 ) = 48.5%), and 1.51 (95% CI 1.26-1.82, I(2 ) = 76.6%), respectively. Subgroup analysis by exposure duration revealed that the strength of the association decreased with a longer window of SSRI administration before the index date. The risk of fracture was greater within 6 weeks before the index date (adjusted OR = 3.83, 95% CI 1.96-7.49, I(2 ) = 41.5%) than 6 weeks or more (adjusted OR = 1.60, 95% CI 0.93-2.76, I(2 ) = 63.1%). Fracture risk associated with SSRI use may have a significant clinical impact. Clinicians should carefully consider bone mineral density screening before prescribing SSRIs and proper management for high-risk populations.

Perinatal citalopram exposure selectively increases locus ceruleus circuit function in male rats.

Selective serotonin reuptake inhibitors (SSRIs), such as citalopram (CTM), have been widely prescribed for major depressive disorder, not only for adult populations, but also for children and pregnant mothers. Recent evidence suggests that chronic SSRI exposure in adults increases serotonin (5-HT) levels in the raphe system and decreases norepinephrine (NE) locus ceruleus (LC) neural activity, suggesting a robust opposing interaction between these two monoamines. In contrast, perinatal SSRI exposure induces a long-lasting downregulation of the 5-HT-raphe system, which is opposite to that seen with chronic adult treatment. Therefore, the goal of the present investigation was to test the hypothesis that perinatal CTM exposure (20 mg/kg/d) from postnatal day 1 (PN1) to PN10 leads to hyperexcited NE-LC circuit function in adult rats (>PN90). Our single-neuron LC electrophysiological data demonstrated an increase in spontaneous and stimulus-driven neural activity, including an increase in phasic bursts in CTM-exposed animals. In addition, we demonstrated a corresponding immunoreactive increase in the rate-limiting catalyzing catecholamine enzyme (tyrosine hydroxylase) within the LC and their neocortical target sites compared to saline controls. Moreover, these effects were only evident in male exposed rats, suggesting a sexual dimorphism in neural development after SSRI exposure. Together, these results indicate that administration of SSRIs during a sensitive period of brain development results in long-lasting alterations in NE-LC circuit function in adults and may be useful in understanding the etiology of pervasive developmental disorders such as autism spectrum disorder.

Differential effects of escitalopram challenge on disgust processing in obsessive–compulsive disorder

Introduction Literature on the ability of patients with obsessive–compulsive disorder (OCD) to recognize static facial expressions of disgust is not consistent. We aimed to investigate whether OCD is associated with deficits in the recognition of disgust in a dynamic task, and if so, whether the acute administration of the selective serotonin reuptake inhibitor (SSRI) escitalopram would result in the normalization of such deficits. Methods OCD patients ( n = 20) and matched healthy controls ( n = 20) received a single dose of escitalopram 20 mg on one day, and a single dose of placebo on another day, in randomized order, under double-blind conditions. Accuracy (i.e. the percentage of correct answers) and sensitivity to disgust stimuli (defined as the lowest level of emotional intensity expressed on the photo image after which no errors were made in the recognition of disgust for subsequent trials of increasing intensity) were compared in OCD patients and controls, with a repeated measures analysis of variance using a mixed model approach. Results On placebo, the accuracy of, and sensitivity to, disgust stimuli were similar across groups. OCD patients had more accurate and more sensitive recognition of disgust after acute SSRI administration than after placebo, while controls had less accurate recognition and less sensitive recognition of disgust after acute SSRI administration than after placebo. Conclusions The use of a dynamic facial recognition task demonstrated altered responses to disgust in OCD patients compared to healthy controls after a pharmacological challenge with escitalopram. These findings suggest that the serotonergic system plays a role in disgust recognition.

Decreased serotonin content and reduced agonist-induced aggregation in platelets of patients chronically medicated with SSRI drugs

Chronic treatment with selective serotonin reuptake inhibitors (SSRIs) reduces the risk and severity of cardiovascular diseases. SSRIs block the serotonin transporter, thereby inhibiting serotonin (5-HT) uptake into presynaptic neurons as well as into platelets where 5-HT is stored in dense granules. When 5-HT is released in response to agonists it enhances platelet aggregation induced by injury-related signals. Chronic administration of SSRIs may thus reduce platelet aggregability secondary to depletion of platelets' serotonin stores. The study included ten DSM-IV-TR major depression (MDD) and four obsessive compulsive disorder (OCD) patients and fourteen healthy untreated age- and sex-matched controls. The patients were chronically medicated (6-108 months) with various SSRIs. Platelet serotonin content was assessed in fresh samples of platelet rich plasma (PRP) using radioimmunoassay. ADP, collagen, arachidonic acid and epinephrine were used as inducers of platelet aggregation measured in PRP by turbometric method in a microplate reader. Lower platelet serotonin content (66%; p<0.05) and lower ADP, collagen or epinephrine-induced platelet aggregation (10-52%; p<0.05) were detected in PRP of SSRI-medicated patients, while no such effect was obtained with arachidonic acid. The small sample size and the co-treatment with non-SSRI drugs such as benzodiazepines. Patients chronically medicated with SSRIs exhibit lower platelet 5-HT content and reduced platelet aggregation induced by ADP, collagen and epinephrine, but not by arachidonic acid. Our observations may explain the increased bleeding risk associated with chronic SSRI treatment as well as the reported beneficial effect of SSRIs in prevention of recurrent myocardial infarction.

5-HTTLPR genotype and gender, but not chronic fluoxetine administration, are associated with cortical TREK1 protein expression in rhesus macaques

TREK1 is a widely expressed background potassium channel. Similar to mice treated with selective serotonin reuptake inhibitors (SSRIs), TREK1 knockout mice are resistant to depression-like behavior and have elevated serotonin levels leading to speculation that TREK1 inhibition may contribute to the therapeutic effects of SSRIs. This study examined how chronic fluoxetine administration and a common functional polymorphism in the serotonin-transporter-linked promoter region (5-HTTLPR) influence cortical TREK1 expression in 24 rhesus monkeys. The short rh5-HTTLPR allele as well as female gender were associated with reduced cortical TREK1 protein expression but chronic SSRI administration had no effect. These results suggest that serotonin may influence TREK1, but that chronic SSRI treatment does not result in long lasting changes in cortical TREK1 protein expression. TREK1 gender differences may be related to gender differences in serotonin and require further research.

Tracking Down the Molecular Substrates of Stress: New Roles for p38α MAPK and Kappa-Opioid Receptors

In this issue, Bruchas etal. (2011) uncover a novel stress-induced p38α MAPK signaling cascade within serotonergic neurons of the dorsal raphe nucleus that mediates depressive and drug-seeking behaviors. Their findings have potentially important implications for medication development.