An open-label trial of riluzole, a glutamate antagonist, in children with treatment-resistant obsessive-compulsive disorder

Pediatric Treatment-Resistant Obsessive Compulsive Disorder: Treatment Options and Challenges

Pediatric obsessive-compulsive disorder (OCD) is a chronic, potentially debilitating psychiatric condition. Although effective treatments exist, at least 10% of youth do not achieve remission despite receiving first-line treatments. This article reviews the extant, albeit limited, evidence supporting treatment approaches for youth with treatment-resistant OCD. A literature search for articles addressing pediatric treatment-resistant OCD was conducted through April 11, 2024. These results were augmented by searching for treatment-resistant OCD in adults; treatment strategies discovered for the adult population were then searched in the context of children and adolescents. In general, intensive treatment programs and antipsychotic augmentation of an antidepressant had the most substantial and consistent evidence base for treatment-resistant youth with OCD, although studies were limited and of relatively poor methodological quality (i.e., open trials, naturalistic studies). Several pharmacological approaches (clomipramine, antipsychotics [e.g., aripiprazole, risperidone], riluzole, ketamine, D-cycloserine, memantine, topiramate, N-acetylcysteine, ondansetron), largely based on supporting data among adults, have received varying levels of investigation and support. There is nascent support for how to treat pediatric treatment-resistant OCD. Future treatment studies need to consider how to manage the significant minority of youth who fail to benefit from first-line treatment approaches.

Effects of riluzole on psychiatric disorders with anxiety or fear as primary symptoms: A systematic review

AIM

Previous behavioral pharmacology studies involving rodents suggested riluzole had potential to be an ideal psychotropic drug for psychiatric disorders with anxiety or fear as primary symptoms. Several clinical studies have recently been conducted. The purpose of this study was to gather information about the efficacy and tolerability of riluzole for patients with those symptoms.

METHODS

We searched PubMed, PsycINFO, CINAHL, EMBASE, and the Cochrane database from inception until April 2021, and performed manual searches for additional relevant articles. This review included: (1) studies involving participants that were patients with generalized anxiety disorder (GAD), social anxiety disorder, panic disorder, obsessive-compulsive disorder (OCD), posttraumatic stress disorder (PTSD), acute stress disorder, or phobias; and (2) randomized controlled trials (RCTs) or intervention studies (e.g., single arm trials) examining the effects and safety of riluzole.

RESULTS

Of the 795 identified articles, four RCTs, one RCT subgroup-analysis, and three open-label trials without control groups met the inclusion criteria. Most trials evaluated the efficacy of riluzole as an augmentation therapy with selective serotonin reuptake inhibitors and other antidepressants for PTSD, OCD, or GAD. However, there was insufficient evidence to confirm the effects of riluzole for patients with these psychiatric disorders. Most trials demonstrated adequate study quality.

CONCLUSIONS

This review found insufficient evidence to confirm the effects of riluzole for psychiatric disorders with anxiety or fear as primary symptoms. It would be worthwhile to conduct studies that incorporate novel perspectives, such as examining the efficacy of riluzole as a concomitant medication for psychotherapy.

Effect of the Metabotropic Glutamate Receptor Type 5 Negative Allosteric Modulator Dipraglurant on Motor and Non-Motor Symptoms of Parkinson's Disease

Parkinson's disease (PD) patients suffer not only from the primary motor symptoms of the disease but also from a range of non-motor symptoms (NMS) that cause disability and low quality of life. Excessive glutamate activity in the basal ganglia resulting from degeneration of the nigrostriatal dopamine pathway has been implicated in the motor symptoms, NMS and dyskinesias in PD patients. In this study, we investigated the effects of a selective mGlu5 negative allosteric modulator (NAM), dipraglurant, in a rodent motor symptoms model of PD, but also in models of anxiety, depression and obsessive-compulsive disorder, all of which are among the most prevalent NMS symptoms. Dipraglurant is rapidly absorbed after oral administration, readily crosses the blood-brain barrier, and exhibits a high correlation between plasma concentration and efficacy in behavioral models. In vivo, dipraglurant dose-dependently reduced haloperidol-induced catalepsy, increased punished licks in the Vogel conflict-drinking model, decreased immobility time in the forced swim test, decreased the number of buried marbles in the marble-burying test, but had no effect on rotarod performance or locomotor activity. These findings suggest that dipraglurant may have benefits to address some of the highly problematic comorbid non-motor symptoms of PD, in addition to its antidyskinetic effect demonstrated in PD-LID patients.

Correlations between single nucleotide polymorphisms in obsessive-compulsive disorder with the clinical features or response to therapy

Obsessive-compulsive disorder (OCD) is a debilitating neuropsychiatric disorder, in which the patient endures intrusive thoughts or is compelled to perform repetitive or ritualized actions. Many cases of OCD are considered to be familial or heritable in nature. It has been shown that a variety of internal and external risk factors are involved in the pathogenesis of OCD. Among the internal factors, genetic modifications play a critical role in the pathophysiological process. Despite many investigations performed to determine the candidate genes, the precise genetic factors involved in the disease remain largely undetermined. The present review summarizes the single nucleotide polymorphisms that have been proposed to be associated with OCD symptoms, early onset disease, neuroimaging results, and response to therapy. This information could help us to draw connections between genetics and OCD symptoms, better characterize OCD in individual patients, understand OCD prognosis, and design more targeted personalized treatment approaches.

Randomized Controlled Trial of Riluzole Augmentation for Posttraumatic Stress Disorder: Efficacy of a Glutamatergic Modulator for Antidepressant-Resistant Symptoms

OBJECTIVE

Current pharmacologic treatments for posttraumatic stress disorder (PTSD) have shown limited efficacy, prompting a call to investigate new classes of medications. The current study investigated the efficacy of glutamate modulation with riluzole augmentation for combat-related PTSD symptoms resistant to treatment with selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs).

METHODS

A randomized, double-blind, placebo-controlled, parallel trial was conducted at Walter Reed National Military Medical Center and Syracuse VA Medical Center between December 2013 and November 2017. Veterans and active duty service members with combat-related PTSD (per the Clinician Administered PTSD Scale [CAPS]) who were not responsive to SSRI or SNRI pharmacotherapy were randomized to 8-week augmentation with a starting dose of 100 mg/d of riluzole (n = 36) or placebo (n = 38) and assessed weekly for PTSD symptoms, anxiety, depression, disability, and side effects.

RESULTS

Intent-to-treat analyses (N = 74) of the primary outcome (CAPS for DSM-IV) showed no significant between-group difference in change in overall PTSD symptoms (F = 0.64, P = .422), with a small effect size (d = 0.25). There was clinically significant within-group improvement in overall PTSD symptoms in both groups, with a greater mean (SD) decrease in CAPS score in the riluzole group (-21.1 [18.9]) than in the placebo group (-16.7 [17.2]). Exploratory analyses of PTSD symptom clusters showed significantly greater improvement on hyperarousal symptoms in the riluzole group as measured by the PTSD Checklist-Specific-Subscale D (d = 0.48) and near-significant findings on the CAPS Subscale D. Riluzole augmentation was not superior to placebo on change in depression, anxiety, or disability severity.

CONCLUSIONS

Although preliminary, the exploratory findings of this study offer some evidence that riluzole augmentation of an SSRI or SNRI may selectively improve PTSD hyperarousal symptoms without changes in overall PTSD symptoms, depression, anxiety, or disability. Additional investigation of the mechanism of the efficacy of riluzole for hyperarousal symptoms is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02155829.

Novel pharmacological treatments for generalized anxiety disorder: Pediatric considerations

BACKGROUND

Pediatric anxiety disorders such as generalized anxiety disorder (GAD) are common, impairing, and often undertreated. Moreover, many youth do not respond to standard, evidence-based psychosocial or psychopharmacologic treatment. An increased understanding of the gamma-aminobutyric acid (GABA) and glutamate neurotransmitter systems has created opportunities for novel intervention development for pediatric GAD.

METHODS

This narrative review examines potential candidates for pediatric GAD: eszopiclone, riluzole, eglumegad (LY354740), pimavanserin, agomelatine.

RESULTS

The pharmacology, preclinical data, clinical trial findings and known side effects of eszopiclone, riluzole, eglumegad (LY354740), pimavanserin, agomelatine, are reviewed, particularly with regard to their potential therapeutic relevance to pediatric GAD.

CONCLUSION

Notwithstanding numerous challenges, some of these agents represent potential candidate drugs for pediatric GAD. Further treatment development studies of agomelatine, eszopiclone, pimavanserin and riluzole for pediatric GAD also have the prospect of informing the understanding of GABAergic and glutamatergic function across development.

Obsessive-compulsive disorder in children and adolescents: epidemiology, diagnosis and management

Obsessive-compulsive disorder (OCD) can be found in about 4% of the general population and is characterized by various compulsions and obsessions that interfere with the person's quality of life from a mild to severe degree. The following discussion reflects on current concepts in this condition, including its epidemiology and etiologic underpinnings (behavioral, neurological, immunological, gastroenterological, as well as genetic). The interplay of PANS and PANDAS are included in this review. In addition, the core concepts of OCD diagnosis, differential diagnosis, and co-morbidities are considered. It is stressed that the quality of life for persons with pediatric OCD as well as for family members can be quite limited and challenged. Thus, principles of management are presented as a guide to improve the quality of life for these persons as much as possible.

Investigating the Role of Glutamate in Obsessive-Compulsive Disorder: Current Perspectives

Glutamate is a ubiquitous excitatory neurotransmitter, which is involved in normal physiology, a variety of central nervous system (CNS) functions, including excitotoxicity and neuronal migration. It is implicated in the pathogenesis of various neuropsychiatric disorders including epilepsy, Parkinson's disease, Alzheimer's dementia, schizophrenia and obsessive compulsive disorder (OCD). Over the years, a growing body of evidence has helped researchers understand the mechanisms underlying glutamatergic involvement in the pathogenesis of these disorders. In this review, we attempt to elucidate the role of glutamate in OCD, which is a chronic psychiatric condition with significant morbidity. This article provides current perspectives on the role played by glutamate in the pathogenesis, clinical symptoms and treatment response in OCD, a critical analysis of existing and emerging evidence, both clinical and preclinical, followed by a summary and future directions.

The Neuronal Glutamate Transporter EAAT3 in Obsessive-Compulsive Disorder

Obsessive compulsive disorder (OCD) is a heterogeneous psychiatric disorder affecting 1%–3% of the population worldwide. About half of OCD afflicted individuals do not respond to currently available pharmacotherapy, which is mainly based on serotonin reuptake inhibition. Therefore, there is a critical need to search novel and improved therapeutic targets to treat this devastating disorder. In recent years, accumulating evidence has supported the glutamatergic hypothesis of OCD, and particularly pointing a potential role for the neuronal glutamate transporter EAAT3. This mini-review summarizes recent findings regarding the neurobiological basis of OCD, with an emphasis on the glutamatergic neurotransmission and EAAT3 as a key player in OCD etiology.

The Glutamate and the Immune Systems: New Targets for the Pharmacological Treatment of OCD

BACKGROUND

In the last decades the pharmacological treatment of obsessivecompulsive disorder (OCD) has been significantly promoted by the effectiveness of selective serotonin (5-HT) reuptake inhibitors (SSRIs) and the subsequent development of the 5-HT hypothesis of OCD. However, since a large majority of patients (between 40% and 60 %) do not respond to SSRIs or strategies based on the modulation of the 5-HT system, it is now essential to search for other possible therapeutic targets.

AIMS

The aim of this paper was to review current literature through a PubMed and Google Scholar search of novel hypotheses and related compounds for the treatment of OCD, with a special focus on the glutammate and the immune systems.

DISCUSSION

The literature indicates that glutamate, the main excitatory neurotransmitter, might play an important role in the pathophysiology of OCD. In addition, a series of clinical studies also supports the potential efficacy of drugs modulating the glutamate system. The role of the immune system alterations in OCD in both children and adults needs to be more deeply elucidated. In children, a subtype of OCD has been widely described resulting from infections driven by group A streptococcus β-hemolitic and belonging to the so-called "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). In adults, available findings are meager and controversial, although interesting.

CONCLUSION

The glutamate and the immune systems represent two intriguing topics of research that hold promise for the development of open novel treatment strategies in OCD.

Behavioral and synaptic alterations relevant to obsessive-compulsive disorder in mice with increased EAAT3 expression

Obsessive-compulsive disorder (OCD) is a severe, chronic neuropsychiatric disorder with a strong genetic component. The SLC1A1 gene encoding the neuronal glutamate transporter EAAT3 has been proposed as a candidate gene for this disorder. Gene variants affecting SLC1A1 expression in human brain tissue have been associated with OCD. Several mouse models fully or partially lacking EAAT3 have shown no alterations in baseline anxiety-like or repetitive behaviors. We generated a transgenic mouse model (EAAT3^glo) to achieve conditional, Cre-dependent EAAT3 overexpression and evaluated the overall impact of increased EAAT3 expression at behavioral and synaptic levels. Mice with EAAT3 overexpression driven by CaMKIIα-promoter (EAAT3^glo/CMKII) displayed increased anxiety-like and repetitive behaviors that were both restored by chronic, but not acute, treatment with fluoxetine or clomipramine. EAAT3^glo/CMKII mice also displayed greater spontaneous recovery of conditioned fear. Electrophysiological and biochemical analyses at corticostriatal synapses of EAAT3^glo/CMKII mice revealed changes in NMDA receptor subunit composition and altered NMDA-dependent synaptic plasticity. By recapitulating relevant behavioral, neurophysiological, and psychopharmacological aspects, our results provide support for the glutamatergic hypothesis of OCD, particularly for the increased EAAT3 function, and provide a valuable animal model that may open novel therapeutic approaches to treat this devastating disorder.

Glutamatergic augmentation strategies in obsessive-compulsive disorder

Proven treatment strategies for obsessive-compulsive disorder (OCD) include pharmacotherapy with serotonin reuptake inhibitors and cognitive behavior therapy (CBT). A significant proportion of patients (25%-30%) fail to respond to these treatment options, necessitating the need for additional treatment options to improve treatment outcomes and quality of life in patients with OCD. Augmentation strategies using various glutamatergic agents have been explored, with diverse outcomes. The aim of this review is to give an overview of the glutamatergic system in the brain with a focus on glutamatergic abnormalities in OCD and to review the existing evidence for various glutamatergic agents used for augmentation.

Altered dopaminergic regulation of the dorsal striatum is able to induce tic-like movements in juvenile rats

Motor tics are sudden, repetitive, involuntary movements representing the hallmark behaviors of the neurodevelopmental disease Tourette’s syndrome (TS). The primary cause of TS remains unclear. The initial observation that dopaminergic antagonists alleviate tics led to the development of a dopaminergic theory of TS etiology which is supported by post mortem and in vivo studies indicating that non-physiological activation of the striatum could generate tics. The striatum controls movement execution through the balanced activity of dopamine receptor D1 and D2-expressing medium spiny neurons of the direct and indirect pathway, respectively. Different neurotransmitters can activate or repress striatal activity and among them, dopamine plays a major role. In this study we introduced a chronic dopaminergic alteration in juvenile rats, in order to modify the delicate balance between direct and indirect pathway. This manipulation was done in the dorsal striatum, that had been associated with tic-like movements generation in animal models. The results were movements resembling tics, which were categorized and scored according to a newly developed rating scale and were reduced by clonidine and riluzole treatment. Finally, post mortem analyses revealed altered RNA expression of dopaminergic receptors D1 and D2, suggesting an imbalanced dopaminergic regulation of medium spiny neuron activity as being causally related to the observed phenotype.

Biochemical markers of striatal desensitization in cortical-limbic hyperglutamatergic TS- & OCD-like transgenic mice

Tics and compulsions in comorbid Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD) are associated with chronic hyperactivity of parallel cortico/amygdalo-striato-thalamo-cortical (CSTC) loop circuits. Comorbid TS- & OCD-like behaviors have likewise been observed in D1CT-7 mice, in which an artificial neuropotentiating transgene encoding the cAMP-elevating intracellular subunit of cholera toxin (CT) is chronically expressed selectively in somatosensory cortical & amygdalar dopamine (DA) D1 receptor-expressing neurons that activate cortico/amygdalo-striatal glutamate (GLU) output. We've now examined in D1CT-7 mice whether the chronic GLU output from their potentiated cortical/limbic CSTC subcircuit afferents associated with TS- & OCD-like behaviors elicits desensitizing neurochemical changes in the striatum (STR). Microdialysis-capillary electrophoresis and in situ hybridization reveal that the mice's chronic GLU-excited STR exhibits pharmacodynamic changes in three independently GLU-regulated measures of output neuron activation, co-excitation, and desensitization, signifying hyperactive striatal CSTC output and compensatory striatal glial and neuronal desensitization: 1) Striatal GABA, an output neurotransmitter induced by afferent GLU, is increased. 2) Striatal d-serine, a glial excitatory co-transmitter inhibited by afferent GLU, is decreased. 3) Striatal Period1 (Per1), which plays a non-circadian role in the STR as a GLU + DA D1- (cAMP-) dependent repressor thought to feedback-inhibit GLU + DA- triggered ultradian urges and motions, is transcriptionally abolished. These data imply that chronic cortical/limbic GLU excitation of the STR desensitizes its co-excitatory d-serine & DA inputs while freezing its GABA output in an active state to mediate chronic tics and compulsions - possibly in part by abolishing striatal Per1-dependent ultradian extinction of urges and motions.

Pharmacotherapy for obsessive—compulsive disorder

We present a narrative review of evidence-based treatment for obsessive–compulsive disorder (OCD), covering first-line pharmacological treatment, augmentation strategies, approaches for treatment-refractory OCD and the management of OCD in special populations (children and adolescents, pregnant and breast-feeding women, and elderly people).

Riluzole Serum Concentration in Pediatric Patients Treated for Obsessive-Compulsive Disorder

PURPOSE/BACKGROUND

The goals of this study were to determine whether pediatric serum concentration of riluzole is similar to that observed in adults and to determine whether riluzole serum concentration is associated with adverse effects or efficacy in children and adolescents with treatment-refractory obsessive-compulsive disorder.

METHODS/PROCEDURES

Data were drawn from previously published studies: 1 open-label trial and 1 randomized controlled trial with an open-label extension phase. Serum was drawn at 24, 36, and 52 weeks in 37 patients who were taking approximately 100 mg riluzole daily (mean dose at 24 weeks, 99 ± 28 mg).

FINDINGS/RESULTS

Across all samples, serum riluzole concentration ranged from 7 to 963 ng/mL. At week 24 (n = 37), the median concentration was 76 ng/mL (interquartile range, 53-172 ng/mL). Within-patient concentration was relatively stable. One subject who had the highest serum concentration levels during the study developed pancreatitis after exiting the study. The patient had recently added fluvoxamine to the riluzole regimen. Controlling for concomitant fluvoxamine (in 6 participants) and time of draw, serum riluzole concentration was not associated with obsessive-compulsive disorder symptom severity, nor was it associated with adverse effect profile.

IMPLICATIONS/CONCLUSIONS

The dose of riluzole used in these pediatric subjects seems to have achieved serum concentration levels similar to those observed in adults. However, as previously reported in adults, the serum concentration had no discernable relationship to efficacy or adverse effects.

UPLC-MS/MS assay of riluzole in human plasma and cerebrospinal fluid (CSF): Application in samples from spinal cord injured patients

In the present study, a sensitive and robust LC-MS/MS method has been developed and validated for the quantification of riluzole in human plasma and cerebrospinal fluid (CSF) in clinical samples from patients with spinal cord injury (SCI). Riluzole and its labeled internal standard (IS) were isolated from plasma and CSF by liquid-liquid extraction using ethyl acetate. Riluzole (m/z 235→166) and IS (m/z 238→169) were detected by electrospray ionization (ESI) using multiple reaction monitoring (MRM) in a positive mode. The assay was linear in the concentration range of 0.5 (LLOQ, signal/noise ratio>10)-800ng/ml in plasma, and 1.0 (LLOQ)-800ng/ml in CSF samples. The intra- and inter-day accuracy in plasma were 94.2-110.0% and 97.8-102.0%, respectively, and those in CSF were 87.6-105.1% and 91.9-98.8%, respectively. The intra- and inter-day precision were 2.2-7.2% and 4.0-9.1%, respectively, in plasma, and 1.4-14.1% and 2.6-11.5%, respectively in CSF. Matrix effect was negligible from both matrices with signal percentages of 97.6-100.6% in plasma and 99.4-106.4% in CSF. The recoveries were >75% in plasma, >84% in CSF with low protein (53.9mg/dl), and >68% in CSF with high protein (348.2mg/dl). This method was successfully applied to quantify riluzole concentrations in plasma and CSF from patients with SCI.

Fragile X targeted pharmacotherapy: lessons learned and future directions

Our understanding of fragile X syndrome (FXS) pathophysiology continues to improve and numerous potential drug targets have been identified. Yet, current prescribing practices are only symptom-based in order to manage difficult behaviors, as no drug to date is approved for the treatment of FXS. Drugs impacting a diversity of targets in the brain have been studied in recent FXS-specific clinical trials. While many drugs have focused on regulation of enhanced glutamatergic or deficient GABAergic neurotransmission, compounds studied have not been limited to these mechanisms. As a single-gene disorder, it was thought that FXS would have consistent drug targets that could be modulated with pharmacotherapy and lead to significant improvement. Unfortunately, despite promising results in FXS animal models, translational drug treatment development in FXS has largely failed. Future success in this field will depend on learning from past challenges to improve clinical trial design, choose appropriate outcome measures and age range choices, and find readily modulated drug targets. Even with many negative placebo-controlled study results, the field continues to move forward exploring both the new mechanistic drug approaches combined with ways to improve trial execution. This review summarizes the known phenotype and pathophysiology of FXS and past clinical trial rationale and results, and discusses current challenges facing the field and lessons from which to learn for future treatment development efforts.

Memantine as an Adjuvant Treatment for Obsessive Compulsive Symptoms in Manic Phase of Bipolar Disorder: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

PURPOSE/BACKGROUND

The aim of this study is to examine the effects of memantine as an adjuvant treatment for obsessive compulsive (OC) symptoms in patients with bipolar disorder (BD) type I, manic phase.

METHODS/PROCEDURES

In this 16-week double-blind placebo-controlled randomized clinical trial, 58 patients in the manic phase of BD who had OC symptoms were randomly allocated to receive memantine or placebo plus their routine medications (lithium + olanzapine + clonazepam). The Yale Brown Obsessive Compulsive Behavior Scale was used to assess the outcomes. Adverse effects were also recorded.

FINDINGS/RESULTS

Thirty-eight patients (19 in the memantine group and 19 in the placebo group) completed the trial. Throughout the trial, the mean score decreased from 20.26 ± 5.91 to 9.73 ± 5.44 in the memantine group (P < 0.000) and from 22.89 ± 5.70 to 16.63 ± 4.00 in the placebo group (P < 0.000). At the end of the study, 15 (78.94%) patients in the memantine group and 7 (36.84%) patients in the placebo group demonstrated more than 34% decline in the Yale Brown Obsessive Compulsive Behavior Scale score (P < 0.01). No serious adverse effects were reported.

IMPLICATIONS/CONCLUSIONS

Our double-blind controlled clinical trial showed that memantine is an effective adjuvant agent for reducing OC symptoms in patients with BD. However, it needs to be noted that our study is preliminary, and larger double-blind controlled studies are needed to confirm the results.

[New developments in the psychotherapeutic and pharmacological treatment of pediatric obsessivecompulsive disorder]

Den Goldstandard in der Behandlung von Zwangsstörungen im Kindes- und Jugendalter stellen die kognitiv-behaviorale Therapie sowie die Medikation mit selektiven Serotonin-Wiederaufnahmehemmern dar. In den letzten Jahren wurden vermehrt auch alternative psychotherapeutische und v. a. psychopharmakologische Behandlungsstrategien untersucht, die möglicherweise bei therapieresistenten Zwangsstörungen erfolgreich sein könnten. Die vorliegende Übersichtsarbeit fasst diese neuen Entwicklungen zusammen, wobei ein Schwerpunkt auf expositionsbezogene psychotherapeutische bzw. pharmakologische Ansätze im glutamatergen System gelegt wurde. Hinsichtlich neuer pharmakologischer Behandlungsoptionen bei Kindern und Jugendlichen unterstreicht die derzeitige Datenlage, v. a. im Hinblick auf den Grad der nachgewiesenen Evidenz sowie mögliche unerwünschte Nebenwirkungen, die Bedeutung einer optimal durchgeführten Kombinationstherapie. Dabei kann diese einer Monotherapie mit kognitiv-behavioraler Therapie im Einzelfall überlegen sein. Eine grundsätzliche Überlegenheit der Kombinationstherapie ist derzeit allerdings nicht nachgewiesen.

Glutamate-Modulating Drugs as a Potential Therapeutic Strategy in Obsessive-Compulsive Disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a mental disease commonly associated with severe distress and impairment of social functioning. Serotonin reuptake inhibitors and/or cognitive behavioural therapy are the therapy of choice, however up to 40% of patients do not respond to treatment. Glutamatergic signalling has also been implicated in OCD. The aim of the current study was to review the clinical evidence for therapeutic utility of glutamate-modulating drugs as an augmentation or monotherapy in OCD patients.

METHODS

We conducted a search of the MEDLINE database for clinical studies evaluating the effect of glutamate-modulating drugs in OCD.

RESULTS

Memantine is the compound most consistently showing a positive effect as an augmentation therapy in OCD. Anti-convulsant drugs (lamotrigine, topiramate) and riluzole may also provide therapeutic benefit to some OCD patients. Finally, ketamine may be of interest due to its potential for a rapid onset of action.

CONCLUSION

Further randomized placebo-controlled trials in larger study populations are necessary in order to draw definitive conclusions on the utility of glutamate-modulating drugs in OCD. Furthermore, genetic and epigenetic factors, clinical symptoms and subtypes predicting treatment response to glutamate-modulating drugs need to be investigated systematically.

Pharmacotherapy for Fragile X Syndrome: Progress to Date

To date, no drug is approved for the treatment of Fragile X Syndrome (FXS) although many drugs are used to manage challenging behaviors from a symptomatic perspective in this population. While our understanding of FXS pathophysiology is expanding, efforts to devise targeted FXS-specific treatments have had limited success in placebo-controlled trials. Compounds aimed at rectifying excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission, as well as other signaling pathways known to be affected by Fragile X Mental Retardation Protein (FMRP) are under various phases of development in FXS. With the failure of several metabotropic glutamate receptor subtype 5 (mGlur5) selective antagonists under clinical investigation, no clear single treatment appears to be greatly effective. These recent challenges call into question various aspects of clinical study design in FXS. More objective outcome measures are under development and validation. Future trials will likely be aimed at correcting multiple pathways known to be disrupted by the loss of FMRP. This review offers a brief summary of the prevalence, phenotypic characteristics, genetic causes and molecular functions of FMRP in the brain (as these have been extensively reviewed elsewhere), discusses the most recent finding in FXS drug development, and summarizes FXS trials utilizing symptomatic treatment.

Riluzole in augmentation of fluvoxamine for moderate to severe obsessive-compulsive disorder: Randomized, double-blind, placebo-controlled study

AIM

The aim of the present randomized, double-blind, placebo-controlled, 8-week trial was to assess the efficacy and tolerability of riluzole augmentation of fluvoxamine in treatment of patients with moderate to severe obsessive-compulsive disorder.

METHODS

Patients were randomized into two parallel groups to receive fluvoxamine plus placebo or fluvoxamine plus riluzole (50 mg twice daily). All patients, regardless of their treatment group, received fluvoxamine at 100 mg/day for the initial 4 weeks of the study followed by 200 mg/day of fluvoxamine for the rest of the trial course. A total of 50 patients (25 in each group) were evaluated for response to treatment using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) at baseline and at weeks 4, 8 and 10. Side-effects were recorded using predesigned checklists in each visit. Repeated-measure analysis of variance showed a significant effect for time × treatment interaction in the Y-BOCS total score and a significant effect for time × treatment interaction in the Y-BOCS Compulsive subscale score between the two groups.

RESULTS

Repeated-measure analysis of variance showed a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 4.07, d.f. = 1.22, P = 0.04) in the Y-BOCS total score and a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 4.45, d.f. = 1.33, P = 0.028) in the Y-BOCS Compulsive subscale score between the two groups. Riluzole augmentation therapy demonstrated higher, partial or complete treatment response according to the Y-BOCS total scores.

CONCLUSION

Riluzole may be of clinical use as an adjuvant agent to fluvoxamine in treatment of moderate to severe obsessive-compulsive disorder.

Management of obsessive-compulsive disorder comorbid with bipolar disorder

Obsessive-compulsive disorder (OCD) is one of the most common comorbidities in bipolar disorder (BD). Clinicians often get perplexed in making treatment decisions when encountering comorbid OCD and BD as treatment of OCD by pharmacotherapy may induce or exacerbate mood instability and psychotherapeutic approaches for OCD may not be feasible in acute manic or depressive state of BD. In this study, we reviewed literature, whether existing guideline-based treatments of BD may be effective in OCD and whether newer agents will be of use for treating this comorbidity. We could find that treatment of such comorbid disorder is largely understudied. Adjuvant topiramate or olanzapine- selective serotonin reuptake inhibitor/clomipramine combination along with mood stabilizer is found to be effective for treating OCD in BD. Use of other conventional pharmacological agents and psychotherapy for treating comorbid OCD in BD lacks evidence and is limited to case reports. Our review also highlights the need for further studies regarding the treatment strategies in this highly prevalent comorbid disorder.

Challenges in developing drugs for pediatric CNS disorders: A focus on psychopharmacology

Many psychiatric and behavioral disorders manifest in childhood (attention deficit hyperactivity disorder, obsessive compulsive disorder, anxiety, depression, schizophrenia, autism spectrum disorder, etc.) and the opportunity for intervening early may attenuate full development of the disorder and lessen long term disability. Yet, pediatric drug approvals for CNS indications are limited, and pediatric testing generally occurs only after establishing adult efficacy, more as an afterthought rather than with the initial goal of developing the medication for a pediatric CNS indication. With pharmaceutical companies decreasing funding of their neuroscience research divisions overall, the prospects for moving promising investigational drugs forward into pediatrics will only decline. The goal of this review is to highlight important challenges around pediatric drug development for psychiatric disorders, specifically during clinical development, and to present opportunities for filling these gaps, using new strategies for de-risking investigational drugs in new clinical trial designs/models. We will first present the current trends in pediatric drug efficacy testing in academic research and in industry trials, we will then discuss the regulatory landscape of pediatric drug testing, including policies intended to support and encourage more testing. Obstacles that remain will then be presented, followed by new designs, funding opportunities and considerations for testing investigational drugs safely.

Addressing the Complexity of Tourette's Syndrome through the Use of Animal Models

Tourette's syndrome (TS) is a neurodevelopmental disorder characterized by fluctuating motor and vocal tics, usually preceded by sensory premonitions, called premonitory urges. Besides tics, the vast majority—up to 90%—of TS patients suffer from psychiatric comorbidities, mainly attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). The etiology of TS remains elusive. Genetics is believed to play an important role, but it is clear that other factors contribute to TS, possibly altering brain functioning and architecture during a sensitive phase of neural development. Clinical brain imaging and genetic studies have contributed to elucidate TS pathophysiology and disease mechanisms; however, TS disease etiology still is poorly understood. Findings from genetic studies led to the development of genetic animal models, but they poorly reflect the pathophysiology of TS. Addressing the role of neurotransmission, brain regions, and brain circuits in TS disease pathomechanisms is another focus area for preclinical TS model development. We are now in an interesting moment in time when numerous innovative animal models are continuously brought to the attention of the public. Due to the diverse and largely unknown etiology of TS, there is no single preclinical model featuring all different aspects of TS symptomatology. TS has been dissected into its key symptomst hat have been investigated separately, in line with the Research Domain Criteria concept. The different rationales used to develop the respective animal models are critically reviewed, to discuss the potential of the contribution of animal models to elucidate TS disease mechanisms.

N-acetylcysteine augmentation therapy for moderate-to-severe obsessive-compulsive disorder: randomized, double-blind, placebo-controlled trial

WHAT IS KNOWN AND OBJECTIVE

N-acetylcysteine (NAC) has been proposed as a potential therapy for obsessive-compulsive disorder (OCD) as it may regulate the exchange of glutamate and prevent its pre-oxidant effects. The aim of the present double-blind, placebo-controlled trial was to assess the efficacy and tolerability of NAC augmentation in moderate-to-severe (OCD) treatment.

METHODS

In this randomized, double-blind, two-centre, placebo-controlled, 10-week trial, patients with moderate-to-severe OCD were enrolled. Patients were randomized into two parallel groups to receive fluvoxamine (200 mg daily) plus placebo or fluvoxamine (200 mg daily) plus NAC (2000 mg daily). A total of 44 patients (22 in each group) were visited to evaluate response to therapy using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) at baseline, and at weeks 4, 8 and 10. Side effects were recorded using predesigned checklists upon each visit.

RESULTS AND DISCUSSION

Repeated-measures ANOVA showed a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 5·14, d.f. = 1·64, P = 0·012) in the Y-BOCS total score and a significant effect for time × treatment interaction (Greenhouse-Geisser corrected: F = 5·44, d.f. = 1·54, P = 0·011) in the Y-BOCS obsession subscale between the two groups.

WHAT IS NEW AND CONCLUSION

Our results showed that NAC might be effective as an augmentative agent in the treatment of moderate-to-severe OCD.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (www.irct.ir): IRCT201405271556N60.

Polymorphisms within the neuronal cadherin (CDH2) gene are associated with obsessive-compulsive disorder (OCD) in a South African cohort

OCD is characterised by recurrent obsessions and compulsions that result in severe distress and increased risk for comorbidity. Recently published findings have indicated that the neuronal cadherin gene (CDH2) plays a role in the development of canine OCD, and led us to investigate the human ortholog, CDH2, in a human OCD cohort. Seven CDH2 polymorphisms were selected and genotyped in a South African Caucasian cohort of 234 OCD patients and 180 healthy controls using TaqMan assays. Polymorphisms were analysed in a single-locus and haplotypic context. Of the seven polymorphisms, two reached statistical significance for OCD under additive and codominant models of inheritance (rs1120154 and rs12605662). CDH2 SNP, rs1120154, C-allele carriers were found to be significantly associated with lower risk to develop OCD compared to TT-homozygotes (OR = 0.49; 95% CI: 0.32-0.75; p < 0.001), and rs12605662 G-allele carriers were significantly associated with reduced risk OCD compared to TT-homozygotes (OR = 0.46; 95% CI: 0.30-0.71; p < 0.001), Furthermore, a single haplotype was found to infer an increased risk for OCD diagnosis (*rs8087457-rs1148374: A-T). Polymorphisms within the CDH2 gene are associated with susceptibility to OCD in a South African cohort.

"Hyperglutamatergic cortico-striato-thalamo-cortical circuit" breaker drugs alleviate tics in a transgenic circuit model of Tourette׳s syndrome

The brain circuits underlying tics in Tourette׳s syndrome (TS) are unknown but thought to involve cortico/amygdalo-striato-thalamo-cortical (CSTC) loop hyperactivity. We previously engineered a transgenic mouse "circuit model" of TS by expressing an artificial neuropotentiating transgene (encoding the cAMP-elevating, intracellular A1 subunit of cholera toxin) within a small population of dopamine D1 receptor-expressing somatosensory cortical and limbic neurons that hyperactivate cortico/amygdalostriatal glutamatergic output circuits thought to be hyperactive in TS and comorbid obsessive-compulsive (OC) disorders. As in TS, these D1CT-7 ("Ticcy") transgenic mice׳s tics were alleviated by the TS drugs clonidine and dopamine D2 receptor antagonists; and their chronic glutamate-excited striatal motor output was unbalanced toward hyperactivity of the motoric direct pathway and inactivity of the cataleptic indirect pathway. Here we have examined whether these mice׳s tics are countered by drugs that "break" sequential elements of their hyperactive cortical/amygdalar glutamatergic and efferent striatal circuit: anti-serotonoceptive and anti-noradrenoceptive corticostriatal glutamate output blockers (the serotonin 5-HT2a,c receptor antagonist ritanserin and the NE alpha-1 receptor antagonist prazosin); agmatinergic striatothalamic GABA output blockers (the presynaptic agmatine/imidazoline I1 receptor agonist moxonidine); and nigrostriatal dopamine output blockers (the presynaptic D2 receptor agonist bromocriptine). Each drug class alleviates tics in the Ticcy mice, suggesting a hyperglutamatergic CSTC "tic circuit" could exist in TS wherein cortical/amygdalar pyramidal projection neurons׳ glutamatergic overexcitation of both striatal output neurons and nigrostriatal dopaminergic modulatory neurons unbalances their circuit integration to excite striatothalamic output and create tics, and illuminating new TS drug strategies.

Riluzole augmentation in treatment-refractory obsessive-compulsive disorder: a pilot randomized placebo-controlled trial

OBJECTIVE

Obsessive-compulsive disorder (OCD) affects approximately 2.5% of the population and is associated with significant morbidity. Many patients receive little benefit from the best available treatments, and even those who do respond often suffer from significant residual symptoms. Convergent evidence suggests that abnormalities in glutamate homeostasis and neurotransmission may contribute to OCD and that glutamate-modulating medications may be of benefit in patients whose symptoms are refractory to standard interventions. Small open-label trials of augmentation of serotonin reuptake inhibitor (SRI) pharmacotherapy with the glutamate modulator riluzole have suggested benefit in adults with refractory symptoms. We report a pilot randomized placebo-controlled trial of riluzole augmentation of ongoing SRI treatment in SRI-refractory patients.

METHOD

Outpatients (n = 27) and inpatients (n = 11) with DSM-IV OCD on stable SRI pharmacotherapy were randomized between November 2006 and December 2012 to receive riluzole 50 mg or placebo twice a day and followed for 12 weeks after a 2-week placebo lead-in phase.

RESULTS

Riluzole was well tolerated; 1 patient experienced moderate nausea, but none discontinued treatment due to side effects. While there was nominally greater Y-BOCS improvement in the riluzole group (our primary outcome) compared to placebo, it did not reach statistical significance. In the outpatient subsample, a trend suggesting benefit from riluzole augmentation for obsessions (P = .056, 2-tailed, uncorrected) was found in a secondary analysis. Among outpatients, more achieved at least a partial response (> 25% improvement) with riluzole than with placebo (P = .02 in a secondary analysis).

CONCLUSIONS

Riluzole may be of benefit to a subset of patients. Larger samples would be required to detect effects of the order suggested by the nominal improvement in our outpatient subsample.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00523718.

Decreased thalamic glutamate level in unmedicated adult obsessive-compulsive disorder patients detected by proton magnetic resonance spectroscopy

BACKGROUND

Previous neuroimaging studies implied that the dysfunction of cortico-striato-thalamo-cortical (CSTC) circuit served as the neural basis for the pathophysiology of obsessive-compulsive disorder (OCD). The imbalances in neuronal metabolite and neurotransmitter within CSTC circuit have been shown as the leading reasons of the OCD onset. The aim of this study is to investigate the metabolic alterations, especially the glutamatergic signal dysfunction within CSTC circuit, and the relationships between neural metabolites and the symptom severity of OCD patients.

METHODS

Single voxel magnetic resonance spectroscopy (MRS) was conducted in medial prefrontal cortex (mPFC) and bilateral thalamus areas for thirteen unmedicated adult OCD patients with age-, gender-, and education-matched healthy controls. Quantification and multivariate analysis were performed to identify vital metabolic biomarkers for patients and healthy controls group differentiation. Moreover, we performed Spearman׳s rank correlation analysis for OCD patients to examine the relationship between the metabolite concentration level and OCD symptomatology.

RESULTS

Patients with OCD showed significantly decreased glutamate level in mPFC (p=0.021) and right thalamus (p=0.039), and significantly increased choline compounds in left thalamus (p=0.044).The glutamate in right thalamus was shown as the most important metabolite for group separation from multivariate analysis (Q(2)=0.134) and was significantly correlated with the patients׳ compulsion scores (Spearman r=-0.674, p=0.016).

LIMITATIONS

Limited sample size, the use of creatine and phosphocreatine (Cr) ratios rather than absolute concentrations and unresolved glutamine (Gln) are limitations of the present study.

CONCLUSION

Our study results consolidated the hypothesis about glutamatergic signaling dysfunction in OCD. To our knowledge, it is the first finding about a reduced thalamic glutamate level in adult unmedicated OCD patients. The dysregulation of glutamate serves as a potential target for the OCD pharmacotherapy and the detailed mechanisms underlying the glutamate alterations within CSTC circuits merit further investigations.

A selective review of glutamate pharmacological therapy in obsessive-compulsive and related disorders

Glutamate, an excitatory central nervous system neurotransmitter, is emerging as a potential alternative pharmacological treatment when compared to gamma-aminobutyric acid (GABA)-, dopamine-, and serotonin-modulating treatments for neuropsychiatric conditions. The pathophysiology, animal models, and clinical trials of glutamate modulation are explored in disorders with underlying inhibitory deficits (cognitive, motor, behavioral) including obsessive–compulsive disorder, attention deficit hyperactivity disorder, Tourette syndrome, trichotillomania, excoriation disorder, and nail biting. Obsessive–compulsive disorder, attention deficit hyperactivity disorder, and grooming disorders (trichotillomania and excoriation disorder) have emerging positive data, although only scarce controlled trials are available. The evidence is less supportive for the use of glutamate modulators in Tourette syndrome. Glutamate-modulating agents show promise in the treatment of disorders of inhibition.

Assessment and management of treatment-refractory obsessive-compulsive disorder in children

OBJECTIVE

To review the assessment and treatment of treatment-refractory pediatric obsessive-compulsive disorder (OCD).

METHOD

A PubMed search was conducted to identify controlled trials in pediatric OCD. In addition, practice guidelines for the treatment of adults and children were further reviewed for references in treatment-refractory OCD across the lifespan.

RESULTS

Pharmacotherapy with selective serotonin reuptake inhibitors (SSRIs) and cognitive-behavioral therapy (CBT) were found to be effective treatments for pediatric OCD. Evidence suggests that CBT is also effective even in pediatric patients with refractory OCD symptoms. Antipsychotic augmentation, raising SSRI dosage, and several glutamate-modulating agents have some evidence of efficacy in adults with treatment-refractory OCD but have not been studied in pediatric populations.

CONCLUSION

Several pharmacological treatment options exist for children with refractory OCD symptoms. However, little evidence-based data exist to guide treatment for our most challenging pediatric OCD patients. Further research is needed to evaluate the efficacy/side effect profile of commonly used interventions in treatment-refractory pediatric OCD.

Riluzole in the prelimbic medial prefrontal cortex attenuates veratrine-induced anxiety-like behaviors in mice

RATIONALE

We previously demonstrated in mice that the activation of prelimbic medial prefrontal cortex (PL) with the sodium channel activator veratrine induces anxiety-like behaviors via NMDA receptor-mediated glutamatergic neurotransmission. Riluzole directly affects the glutamatergic system and has recently been suggested to have an anxiolytic-like effect in both experimental animals and patients with anxiety disorders.

OBJECTIVES

We investigated the effects of co-perfusion of riluzole on veratrine-induced anxiety-like behaviors in mice.

METHODS

Extracellular glutamate levels were measured in 7-week-old male C57BL6 mice by using an in vivo microdialysis-HPLC/ECD system, and behaviors were assessed simultaneously in an open field (OF) test. Basal levels of glutamate were measured by collecting samples every 10 min for 60 min. The medium containing drugs was perfused for 30 min, and the OF test was performed during the last 10 min of drug perfusion. After the drug treatments, the drug-containing medium was switched to perfusion of control medium lacking drugs, and then samples were collected for another 90 min.

RESULTS

Riluzole co-perfusion attenuated veratrine-induced increase in extracellular glutamate levels in the PL and completely diminished veratrine-induced anxiety-like behaviors. Interestingly, riluzole perfusion alone in the PL did not affect the basal levels of glutamate and anxiety-like behaviors.

CONCLUSIONS

Our results suggest that compounds like riluzole that inhibit glutamatergic function in the PL are possible candidates for novel anxiolytics.

Animal models of obsessive-compulsive disorder: utility and limitations

Obsessive-compulsive disorder (OCD) is a disabling and common neuropsychiatric condition of poorly known etiology. Many attempts have been made in the last few years to develop animal models of OCD with the aim of clarifying the genetic, neurochemical, and neuroanatomical basis of the disorder, as well as of developing novel pharmacological and neurosurgical treatments that may help to improve the prognosis of the illness. The latter goal is particularly important given that around 40% of patients with OCD do not respond to currently available therapies. This article summarizes strengths and limitations of the leading animal models of OCD including genetic, pharmacologically induced, behavioral manipulation-based, and neurodevelopmental models according to their face, construct, and predictive validity. On the basis of this evaluation, we discuss that currently labeled "animal models of OCD" should be regarded not as models of OCD but, rather, as animal models of different psychopathological processes, such as compulsivity, stereotypy, or perseverance, that are present not only in OCD but also in other psychiatric or neurological disorders. Animal models might constitute a challenging approach to study the neural and genetic mechanism of these phenomena from a trans-diagnostic perspective. Animal models are also of particular interest as tools for developing new therapeutic options for OCD, with the greatest convergence focusing on the glutamatergic system, the role of ovarian and related hormones, and the exploration of new potential targets for deep brain stimulation. Finally, future research on neurocognitive deficits associated with OCD through the use of analogous animal tasks could also provide a genuine opportunity to disentangle the complex etiology of the disorder.

12-week, placebo-controlled trial of add-on riluzole in the treatment of childhood-onset obsessive-compulsive disorder

Many children with childhood-onset obsessive-compulsive disorder (OCD) fail to respond adequately to standard therapies. Evidence from preclinical and clinical studies suggests that the glutamatergic neurotransmitter system might be an alternative treatment target. This study examined the efficacy of riluzole, a glutamatergic modulator, as an adjunctive therapy for children with treatment-resistant OCD. In a 12-week, double-blind, placebo-controlled study, 60 treatment-resistant children and adolescents (mean age=14.5 ± 2.4 years), with moderate to severe OCD (mean Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS)=28.2 ± 3.7), 17 of whom also had concomitant autism spectrum disorder, were randomized to receive riluzole (final dose of 100 mg/day) or placebo in addition to the existing treatment regimen. Fifty-nine subjects completed the randomized trial. Primary outcome measures were changes on the CY-BOCS, the Clinical Global Impressions Scale, and the Children's Global Assessment Scale. Riluzole was fairly well tolerated, although it was associated with one case of pancreatitis and five instances of slight increases in transaminases. All subjects showed significant reductions in CY-BOCS scores during treatment; however, there was no significant difference between placebo and riluzole on any of the primary or secondary outcome measures. The study failed to demonstrate superiority of riluzole over placebo as an adjunctive treatment for children with childhood-onset OCD. However, future studies may show benefits for less treatment-refractory children with fewer concomitant medications.

Psychopharmacological interventions in autism spectrum disorder

After participating in this educational activity, the physician should be better able to1. Prescribe the appropriate psychotropic medication to treat symptoms of ASD.2. Identify the side effects of the psychotropic medications used to treat ASD.Autism spectrum disorders (ASDs) are characterized by core deficits in social communication and language, and restrictive and repetitive behaviors that cause significant functional impairment and distress for affected individuals and their caregivers. The increasing prevalence of ASD, most recently estimated as 1 in 88 children, presents an ever-increasing burden on families, schools, medical systems, and society at large. Individuals with ASD commonly present for treatment of associated emotional and behavioral disturbances that include anxiety, symptoms of ADHD, compulsions and other repetitive behaviors, mood lability, irritability, aggression, and sleep disturbance. Psychotropic medications are widely utilized in alleviating these symptoms, though rigorous clinical trials in ASD are lacking for most areas of impairment. Strong evidence from randomized, placebo-controlled trials supports the use of atypical antipsychotics, particularly risperidone and aripiprazole, for managing severe irritability and aggression in ASD. Serotonin reuptake inhibitors are commonly used to treat anxiety and compulsions, though reports of efficacy in the literature are mixed, and behavioral side effects in children are common. Minimal evidence supports the utility of anticonvulsants and traditional mood stabilizers in managing mood lability and aggression. Stimulant and nonstimulant ADHD medications can be effective for reducing hyperactivity, inattention, and impulsivity, though to a lesser degree than in ADHD populations without ASD and with greater risk of adverse effects. Psychopharmacological interventions in development for core symptoms of autism include those that target the glutamatergic and GABAergic neurotransmitter systems and the neuropeptide oxytocin. Further research is needed to establish evidence-based interventions in ASD populations.

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common heterogeneous psychiatric disorder manifesting with obsessions and compulsions. Obsessions are intrusive, recurrent, and persistent unwanted thoughts. Compulsions are repetitive behaviors or mental acts that an individual feels driven to perform in response to the obsessions. The heterogeneity of OCD includes themes of obsessions, types of rituals, presence or absence of tics, etiology, genetics, and response to pharmacotherapy. Complications of OCD include interpersonal difficulties, unemployment, substance abuse, criminal justice issues, and physical injuries. Areas of the brain involved in the pathophysiology include the orbitofrontal cortex, anterior cingulate gyrus, and basal ganglia. Overall, OCD may be due to a malfunction in the cortico-striato-thalamo-cortical circuit in the brain. Neurotransmitters implicated in OCD include serotonin, dopamine, and glutamate. Numerous drugs such as atypical antipsychotics and dopaminergic agents can cause or exacerbate OCD symptoms. The etiology includes genetics and neurological insults. Treatment of OCD includes psychotherapy, pharmacotherapy, electroconvulsive therapy, transcranial magnetic simulation, and in extreme cases surgery. Exposure and response prevention is the most effective form of psychotherapy. Selective serotonin reuptake inhibitors (SSRIs) are the preferred pharmacotherapy. Higher doses than listed in the package insert and a longer trial are often needed for SSRIs than compared to other psychiatric disorders. Alternatives to SSRIs include clomipramine and serotonin/norepinephrine reuptake inhibitors. Treatment of resistant cases includes augmentation with atypical antipsychotics, pindolol, buspirone, and glutamate-blocking agents.

Treatment of pediatric anxiety disorders

This article provides a brief review of the current available data concerning present treatment and potential new treatment advances for pediatric anxiety disorders, such as generalized anxiety disorder, separation anxiety disorder, social phobia, obsessive-compulsive disorder, and posttraumatic stress disorder. Disorder-specific treatment methods and innovations, particularly computer-assisted methods of delivery for cognitive behavioral therapy (CBT) will be reviewed. Additionally, the paper will discuss novel psychopharmacological compounds (e.g., D-cycloserine, riluzole, memantine, and anticonvulsant medications). Available evidence for the efficacy of novel medication strategies in adult studies and implications for their use in pediatrics will be discussed.

A double-blind, placebo controlled, randomized trial of riluzole as an adjunct to risperidone for treatment of negative symptoms in patients with chronic schizophrenia

RATIONALE

Several recent studies have focused on glutamate modulating agents for symptoms relief in schizophrenia, especially negative symptoms which are resistant to conventional therapies.

OBJECTIVES

We aimed to assess the efficacy and tolerability of riluzole, an anti-glutamate agent with neuroprotective properties, as an adjunct to risperidone in improving negative symptoms of schizophrenia.

METHODS

In this randomized double-blind placebo-controlled parallel-group study, 50 patients with chronic schizophrenia and a score of ≥20 on the negative subscale of positive and negative syndrome scale (PANSS) were enrolled in the active phase of their illness. Participants were equally randomized to receive riluzole (100 mg/day) or placebo in addition to risperidone (up to 6 mg/day) for 8 weeks. Participants were rated by PANSS every 2 weeks. The primary outcome of this study was the difference in the decrease of PANSS negative subscale score from baseline to the study endpoint between the two groups.

RESULTS

By the study endpoint, riluzole-treated patients showed significantly greater improvement in the negative symptoms (P < 0.001) as well as the PANSS total and general psychopathology subscale scores (P = 0.001 and P < 0.001; respectively) compared to the placebo group. Treatment group was the only significant predictor of changes in negative symptom in this trial (β = -0.56, P < 0.001). No significant difference was observed between two groups in the frequency of side effects.

CONCLUSION

These preliminary findings suggest that riluzole may be a safe and effective medication for the treatment of negative symptoms in patients with chronic schizophrenia. Further research and replication of study findings is warranted. Clinical trial registry name and registration number: Iranian registry of clinical trials www.irct.ir , IRCT201107281556N26

Pharmacological, experimental therapeutic, and transcranial magnetic stimulation treatments for compulsivity and impulsivity

Obsessive-compulsive disorder (OCD) has been recently drawn apart from anxiety disorder by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and clustered together with related disorders (eg, hoarding, hair pulling disorder, skin picking), which with it seems to share clinical and neurophysiological similarities. Recent literature has mainly explored brain circuitries (eg, orbitofrontal cortex, striatum), molecular pathways, and genes (eg, Hoxb8, Slitrk5, Sapap3) that represent the new target of the treatments; they also lead the development of new probes and compounds. In the therapeutic field, monotherapy with cognitive behavioral therapy (CBT) or selective serotonin reuptake inhibitors (SSRIs) is recommendable, but combination or augmentation with a dopaminergic or glutamatergic agent is often adopted. A promising therapy for OCD is represented by repetitive transcranial magnetic stimulation (rTMS), which is suitable to treat compulsivity and impulsivity depending on the protocol of stimulation and the brain circuitries targeted.