A randomized double-blind placebo-controlled clinical trial of adjuvant buspirone for irritability in autism

Psychopharmacology Management in Autism Spectrum Disorder

Persons with autism spectrum disorder (ASD) may have other psychiatric conditions that warrant treatment. Symptoms may not be easy to discern from rigidity or irritability that are sometimes considered to be constituent parts of ASD. Pathophysiology that involves hyperexcitable neurons and anomalous connectivity may provide justification for using psychopharmacologic agents, although nonmedical strategies may also be effective. Hyperactivity, irritability, and tantrums with or without aggression may be rational targets for psychopharmacological intervention. The best-studied drug class to date has been the second-generation antipsychotics targeting irritability.

Off-label psychopharmacological interventions for autism spectrum disorders: strategic pathways for clinicians

The prevalence of autism spectrum disorder (ASD) continues to see a trend upward with a noticeable increase to 1 in 36 children less than 8 years of age in the recent MMWR. There are many factors linked to the substantially increased burden of seeking mental health services, and clinically these individuals are likely to present for impairments associated with co-occurring conditions. The advances in cutting-edge research and the understanding of co-occurring conditions in addition to psychosocial interventions have provided a window of opportunity for psychopharmacological interventions given the limited availability of therapeutics for core symptomatology. The off-label psychopharmacological treatments for these co-occurring conditions are central to clinical practice. However, the scattered evidence remains an impediment for practitioners to systematically utilize these options. The review collates the crucial scientific literature to provide stepwise treatment alternatives for individuals with ASD; with an aim to lead practitioners in making informed and shared decisions. There are many questions about the safety and tolerability of off-label medications; however, it is considered the best practice to utilize the available empirical data in providing psychoeducation for patients, families, and caregivers. The review also covers experimental medications and theoretical underpinnings to enhance further experimental studies. In summary, amidst the growing clinical needs for individuals with ASD and the lack of approved clinical treatments, the review addresses these gaps with a practical guide to appraise the risk and benefits of off-label medications.

Buspirone in Autism Spectrum Disorder: A Systematic Review

The aim of this systematic review is to appraise the current evidence on the efficacy and safety of buspirone in core symptoms of autism spectrum disorder (ASD), co-occurring anxiety, and other associated symptoms. Major medical literature databases were searched for randomized controlled trials (RCTs), open-label trials, and any other relevant studies or clinical trials reporting on pediatric (age < 18 years) patients with ASD treated with buspirone for any reason. A total of 310 abstracts were screened, and six clinical trials were selected for inclusion. Out of these six clinical trials, two were RCTs (n =166 and 40), two open-label trials (n= 26 and 4), and one cross-over study (n = 1). We also included one retrospective chart review (n=31). Meta-analysis was not performed due to a lack of homogeneity in the two RCTs. Although most of the studies reported improved overall symptoms, they had different outcome measures. The quality of evidence available is low, and there is a need for higher-power studies in the future. Most studies suggested that buspirone was well tolerated and safe in pediatric patients with ASD. Based on the data, there is insufficient evidence to make conclusive recommendations on buspirone for improvement in core symptoms of ASD or cooccurring anxiety, irritability, or hyperactivity symptoms in the pediatric population. Given there are limited approved therapies for co-occurring anxiety, buspirone could be used as a safe off-label option due to the lack of behavioral activation and any serious adverse reactions.

Systematic Review and Meta-analysis: Pharmacological and Nonpharmacological Interventions for Persistent Nonepisodic Irritability

OBJECTIVE

This meta-analysis examined the efficacy of available pharmacological and nonpharmacological interventions for irritability among youth with autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), disruptive behavior disorders (DBD), disruptive mood dysregulation disorder (DMDD), and/or severe mood dysregulation (SMD).

METHOD

Literature searches were conducted in October 2020, resulting in 564 abstracts being reviewed to identify relevant papers, with 387 articles being reviewed in full. A random effects model was used for the meta-analysis, with subgroup meta-regressions run to assess effects of study design, intervention type, medication class, and clinical population.

RESULTS

A total of 101 studies were included (80 pharmacological, 13 nonpharmacological, 8 combined). Despite high heterogeneity in effects (I2 = 94.3%), pooled posttreatment effect size for decreasing irritability was large (Hedges' g = 1.62). Large effects were found for pharmacological (g = 1.85) and nonpharmacological (g = 1.11) interventions; moderate effects were found for combined interventions relative to monotherapy interventions (g = 0.69). Antipsychotic medications provided the largest effect for reducing irritability relative to all other medication classes and nonpharmacological interventions. A large effect was found for youth with ASD (g = 1.89), whereas a medium effect was found for youth with ADHD/DMDD/DBD/SMD (g = 0.64).

CONCLUSION

This meta-analysis provides a comprehensive review of interventions targeting persistent nonepisodic irritability among youth with various psychiatric disorders. Strong evidence was found for medium-to-large effects across study design, intervention type, and clinical populations, with the largest effects for pharmacological interventions, particularly antipsychotic medications and combined pharmacological interventions, and interventions for youth with ASD.

Inhibition of Axitinib on Buspirone Metabolism in vitro and in vivo

Objective

To evaluate the effect of axitinib on buspirone metabolism in vitro and in vivo.

Methods

A microsome incubation assay was performed to study the effect and mechanism of axitinib on buspirone metabolizing. In vivo, buspirone was administered with or without axitinib to Sprague–Dawley rats. Plasma samples were collected and subjected to ultra-performance liquid chromatography–tandem mass spectrometry.

Results

In both human liver microsomes (HLMs) and rat liver microsomes (RLMs), axitinib (100 μM) decreased buspirone hydroxylation and N-dealkylation by >85%. Axitinib inhibited buspirone hydroxylation and N-dealkylation, with an IC₅₀ of 15.76 and 9.74 for RLMs, and 10.63 and 9.902 for HLMs. Axitinib showed noncompetitive inhibition of both 6′-hydroxylation and N-dealkylation. Moreover, coadministration of axitinib and buspirone led to an increase in the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC) of buspirone by 4.3- and 5.3-fold, respectively, compared with the control group.

Conclusion

Axitinib inhibited buspirone metabolism in vivo and in vitro, which increases the risk of the side effects of buspirone in the clinic. When coadministered with axitinib, a lower dosage of buspirone should be defined to avoid a toxic response. Axitinib is suspected to function as an inhibitor of CYP3A4.

Sex differences in neuronal systems function and behaviour: beyond a single diagnosis in autism spectrum disorders

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that is associated with functional brain alterations that underlie the expression of behaviour. Males are diagnosed up to four times more than females, and sex differences have been identified in memory, cognitive flexibility, verbal fluency, and social communication. Unfortunately, there exists a lack of information on the sex-dependent mechanisms of ASD, as well as biological markers to distinguish sex-specific symptoms in ASD. This can often result in a standardized diagnosis for individuals across the spectrum, despite significant differences in the various ASD subtypes. Alterations in neuronal connectivity and oscillatory activity, such as is observed in ASD, are highly coupled to behavioural states. Yet, despite the well-identified sexual dimorphisms that exist in ASD, these functional patterns have rarely been analyzed in the context of sex differences or symptomology. This review summarizes alterations in neuronal oscillatory function in ASD, discusses the age, region, symptom and sex-specific differences that are currently observed across the spectrum, and potential targets for regulating neuronal oscillatory activity in ASD. The need to identify sex-specific biomarkers, in order to facilitate specific diagnostic criteria and allow for more targeted therapeutic approaches for ASD will also be discussed.

Randomised controlled trials of antidepressant and anti-anxiety medications for people with autism spectrum disorder: systematic review and meta-analysis

BACKGROUND

Although widely used, the current evidence for the efficacy of antidepressant and anti-anxiety medications for people with autism spectrum disorder (ASD) is limited and conflicting.

AIMS

We carried out a systematic review and meta-analysis of randomised controlled trials that assessed the effectiveness of these medications in people with ASD.

METHOD

We searched the following databases: Cochrane Library, Medline, EMBASE, CINAHL, PsycINFO, ERIC, DARE and ClinicalTrials.gov. Additionally, we hand-searched 11 relevant journals. We used the Cochrane risk-of-bias tool and Jadad score to assess the quality of each included study. We carried out a meta-analysis using a random effects model.

RESULTS

We included 15 randomised controlled trials (13 on antidepressants and two on anti-anxiety medications) for a total of 958 people with ASD. Data showed contradictory findings among the studies, with larger studies mostly showing a non-significant difference in outcomes between the treatment and the placebo groups. Meta-analysis of pooled Yale-Brown Obsessive Compulsive Scale and Clinical Global Impression Scale data from nine studies (60%) did not show any statistically significant inter-group difference on either of the outcome measures. The adverse effects reported were mild and, in most studies, their rates did not show any significant inter-group difference.

CONCLUSIONS

Given the methodological flaws in the most included studies and contradictory findings, it is difficult to draw any definitive conclusion about the effectiveness of either antidepressant or anti-anxiety medications to treat either ASD core symptoms or associated behaviours. Robust, large-scale, randomised controlled trials are needed to address this issue.

The pediatric psychopharmacology of autism spectrum disorder: A systematic review - Part I: The past and the present

Autism Spectrum Disorder (ASD) is a severe and lifelong neurodevelopmental disorder, with high social costs and a dramatic burden on the quality of life of patients and family members. Despite its high prevalence, reaching 1/54 children and 1/45 adults in the United States, no pharmacological treatment is still directed to core symptoms of ASD, encompassing social and communication deficits, repetitive behaviors, restricted interests, and abnormal sensory processing. The purpose of this review is to provide an overview of the state-of-the-art of psychopharmacological therapy available today for ASD in children and adolescents, in order to foster best practices and to organize new strategies for future research. To date, atypical antipsychotics such as risperidone and aripiprazole represent the first line of intervention for hyperactivity, impulsivity, agitation, temper outbursts or aggression towards self or others. Tricyclic antidepressants are less prescribed because of uncertain efficacy and important side effects. SSRIs, especially fluoxetine and sertraline, may be effective in treating repetitive behaviors (anxiety and obsessive-compulsive symptoms) and irritability/agitation, while mirtazapine is more helpful with sleep problems. Low doses of buspirone have shown some efficacy on restrictive and repetitive behaviors in combination with behavioral interventions. Stimulants, and to a lesser extent atomoxetine, are effective in reducing hyperactivity, inattention and impulsivity also in comorbid ASD-ADHD, although with somewhat lower efficacy and greater incidence of side effects compared to idiopathic ADHD. Clonidine and guanfacine display some efficacy on hyperactivity and stereotypic behaviors. For several other drugs, case reports and open-label studies suggest possible efficacy, but no randomized controlled trial has yet been performed. Research in the pediatric psychopharmacology of ASD is still faced with at least two major hurdles: (a) Great interindividual variability in clinical response and side effect sensitivity is observed in the ASD population. This low level of predictability would benefit from symptom-specific treatment algorithms and from biomarkers to support drug choice; (b) To this date, no psychoactive drug appears to directly ameliorate core autism symptoms, although some indirect improvement has been reported with several drugs, once the comorbid target symptom is abated.

Impact of antipsychotics in children and adolescents with autism spectrum disorder: a systematic review and meta-analysis

Background

The net health benefit of using antipsychotics in children and adolescents with ASD is unclear. This review was performed to provide the evidence necessary to inform the Italian national guidelines for the management of ASD.

Methods

We performed a systematic review of randomized controlled trials (RCTs) comparing antipsychotics versus placebo for the treatment of ASD in children and adolescents. For efficacy, acceptability and safety we considered outcomes evaluated by the guideline panel critical and important for decision-making. Continuous outcomes were analyzed by using standardized mean difference (SMD), and dichotomous outcomes by calculating the risk ratio (RR), with their 95% confidence interval (95% CI). Data were analyzed using a random effects model. We used the Cochrane tool to assess risk of bias of included studies. Certainty in the evidence of effects was assessed according to the GRADE approach.

Results

We included 21 RCTs with 1,309 participants, comparing antipsychotics to placebo. Antipsychotics were found effective on “restricted and repetitive interests and behaviors” (SMD − 0.21, 95% CI − 0.35 to − 0.07, moderate certainty), “hyperactivity, inattention, oppositional, disruptive behavior” (SMD − 0.67, 95% CI − 0.92 to − 0.42, moderate certainty), “social communication, social interaction” (SMD − 0.38, 95% CI − 0.59 to − 0.16, moderate certainty), “emotional dysregulation/irritability” (SMD − 0.71, 95% CI − 0.98 to − 0.43, low certainty), “global functioning, global improvement” (SMD − 0.64, 95% CI − 0.96 to − 0.33, low certainty), “obsessions, compulsions” (SMD − 0.30, 95% CI − 0.55 to − 0.06, moderate certainty). Antipsychotics were not effective on “self-harm” (SMD − 0.14, 95% CI − 0.58 to 0.30, very low certainty), “anxiety” (SMD − 0.38, 95% CI − 0.82 to 0.07, very low certainty). Antipsychotics were more acceptable in terms of dropout due to any cause (RR 0.61, 95% CI 0.48 to 0.78, moderate certainty), but were less safe in terms of patients experiencing adverse events (RR 1.19, 95% CI 1.07 to 1.32, moderate certainty), and serious adverse events (RR 1.07, 95% CI 0.48 to 2.43, low certainty).

Conclusions

Our systematic review and meta-analysis found antipsychotics for children and adolescents with ASD more efficacious than placebo in reducing stereotypies, hyperactivity, irritability and obsessions, compulsions, and in increasing social communication and global functioning. Antipsychotics were also found to be more acceptable, but less safe than placebo.

Symptom scores and medication treatment patterns in children with ADHD versus autism

Most children with autism have ADHD, and children with ADHD-Combined and children with autism have high rates of irritable, oppositional, and aggressive behavior. Despite similar symptoms, prescribing practices may differ between autism and ADHD, which has not been examined in a single study. 1407 children with autism and 1036 with ADHD without autism, 2-17 years, were compared with 186 typical peers. Symptom scores were maternal Pediatric Behavior Scale ratings in eight areas (ADHD, oppositional/aggressive, irritable/angry, anxious, depressed, and social, writing, and learning problems). Psychotropics were prescribed to 38.0% with ADHD-Combined, 33.3% with autism, and 20.2% with ADHD-Inattentive, most often an ADHD medication (22.1% stimulant, 2.3% atomoxetine), antipsychotic (7.8%), SSRI (5.5%), and alpha agonist (4.9%). ADHD medications were more often prescribed than other medications in all diagnostic groups. Compared to autism, children with ADHD-Combined were more likely to be prescribed an ADHD medication, whereas antipsychotics and SSRIs were more likely to be prescribed in autism than in ADHD-Combined. Children with ADHD-Inattentive were least impaired and least likely to be medicated. More severely impaired children were more often medicated regardless of diagnosis. Symptom scores were far worse for treated and untreated children with ADHD and with autism than for typical peers.

Management of Self-injurious Behaviors in Children with Neurodevelopmental Disorders: A Pharmacotherapy Overview

Neurodevelopmental disorders (NDDs), a group of disorders affecting ~1-2% of the general population, are caused by changes in brain development that result in behavioral and cognitive alterations, sensory and motor changes, and speech and language deficits. Neurodevelopmental disorders encompass a heterogeneous group of disorders including, but not limited to, Smith-Magenis syndrome, Lesch-Nyhan disease, cri du chat syndrome, Prader-Willi syndrome, pervasive developmental disorders, fragile X syndrome, Rett syndrome, Cornelia de Lange syndrome, and Down syndrome. Self-injurious behaviors (SIBs) are common in children with NDDs; depending on the specific NDD, the incidence of SIBs is nearly 100%. The management of SIBs in this population is complex, and little high-quality data exist to guide a consistent approach to therapy. However, managing SIBs is of the utmost importance for the child as well as the family and caregivers. Behavior therapies must be implemented as first-line therapy. If behavioral interventions alone fail, pharmacotherapy becomes an essential part of management plans. The limited available evidence for the use of common pharmacologic agents, such as second-generation antipsychotics, and less common agents, such as clonidine, n-acetylcysteine, riluzole, naltrexone, and topical anesthetics, is reviewed. Additional data from well-designed studies in children with NDDs are needed to gain a better understanding of this common and troublesome problem including efficacy and safety implications associated with pharmacotherapy. Until then, clinicians must rely on the limited available data, clinical expertise, and ongoing systematic monitoring when managing SIBs in children with NDDs.

Rating of the Effectiveness of 26 Psychiatric and Seizure Medications for Autism Spectrum Disorder: Results of a National Survey

OBJECTIVE

The objective of this study was to provide an evaluation of the benefits and adverse effects (AEs) of psychiatric and seizure medications commonly used for individuals with autism spectrum disorder (ASD).

METHODS

As part of the National Survey on Treatment Effectiveness for Autism, we report ratings of 26 psychiatric and seizure medications by 505 participants. Each medication was rated with a standardized scale for overall benefits, overall AEs, and specific symptoms affected. The frequency of use and net perceived benefit (overall benefit minus overall AE) are reported.

RESULTS

Most medications were rated as having a slightly greater benefit than AE. Six medications (lamotrigine, oxcarbazepine, clonidine, guanfacine, buspirone, and sertraline) had benefit ratings that were more than twice their adverse rating. Conversely, some medications had slightly negative net benefit ratings (worse AEs than benefits on average), including Adderall, Paroxetine, Quetiapine, Olanzapine, and Topiramate. However, there were wide variations in individual ratings of benefit and AEs, suggesting that clinical response to medications was highly variable, so these scores simply represent averages. A ranking of the top medications (those with the highest net perceived benefit) for each of 18 different symptoms is provided, which may provide some clinical guidance as to which medications may be most worth considering for a given symptom. A comparison of the survey results with the results of clinical trials shows generally good agreement in terms of medication benefits with some differences; in some cases the differences are because the clinical trials did not assess all of the symptoms assessed by this survey.

CONCLUSIONS

It is hoped that physicians and their patients will find the survey results useful in selecting the most promising medications for a given symptom, and also for monitoring for likely benefits and AEs, especially for medications for which few or no studies have been carried out in ASD populations.

A Retrospective Chart Review of Buspirone for the Treatment of Anxiety in Psychiatrically Referred Youth with High-Functioning Autism Spectrum Disorder

OBJECTIVES

Anxiety disorders (ADs) are commonly associated with high-functioning Autism Spectrum Disorder (HF-ASD) and often worsen with age. Buspirone is a commonly prescribed anxiolytic drug with a favorable tolerability profile that may offer potential benefits in anxiety management for patients with HF-ASD. This study examines inadequately explored tolerability and effectiveness of buspirone in treating ADs comorbid with high-functioning ASD.

METHODS

A retrospective chart review of a 1-year period was conducted in psychiatrically referred population of HF-ASD youth with AD (age 8-17 years) who were treated with buspirone (N = 31). Information on the demographics and treatment history was recorded. Effectiveness was assessed through the Clinical Global Impressions Scale (CGI) severity (CGI-S) and improvement (CGI-I) scores noted by the treating clinician.

RESULTS

A total of 31 patients were prescribed buspirone during the determined period, at a mean dose of 41.61 ± 24.10 mg for an average duration of 272 ± 125 days. Change in the CGI-S mean scores with treatment suggests an overall improvement in the severity of anxiety symptoms (M_T1 = 4.9 ± 0.7; M_T2 = 2.8 ± 0.87; p < 0.001). Significant improvement in anxiety symptoms (CGI-I ≤ 2) was observed in 58% and mild improvement (CGI-I = 3) in 29% of the HF-ASD patients who received buspirone treatment. Buspirone was well tolerated with no adverse events reported by the majority of participants, with the exception of two subjects who developed treatment emergent adverse events (activation and mood lability).

CONCLUSIONS

Findings from this retrospective chart review suggest a promising role of buspirone in managing anxiety among youth with HF-ASD. Further research with prospective and randomized-controlled trials is necessary.

The effect of stimulants on irritability in autism comorbid with ADHD: a systematic review

Introduction: While there is a very high rate of comorbidity of autism and ADHD, there are controversies about prescribing stimulants in children with autism. This is a systematic review about the effect of stimulants on irritability in children with both autism and ADHD. Methods: A systematic review was conducted to study the possible effect of stimulants on irritability in autism and ADHD using the databases of PubMed, Scopus, EMBASE, and ScienceDirect in September 2018. Eligible clinical trials of stimulants in the treatment of Autism and ADHD without restriction of language were included. The primary outcome was irritability score. The full texts of relevant articles were studied, and their references were scanned for any possible related article. Results: Out of 1,315 citations, there were 26 relevant articles. Of the relevant articles, 16 were not interventional studies and were excluded. There were 10 interventional studies. None of them considered irritability as a main outcome. Also, none of them studied the effect of stimulants on irritability in autism plus ADHD. Current uncontrolled evidence about the association of stimulants with irritability is controversial. Conclusion: The current evidence is not enough to support or discourage the effect of stimulants on irritability in children and adolescents with both autism and ADHD. Well-designed controlled clinical trials need to be conducted for this ignored research area.

Systematic review and guide to management of core and psychiatric symptoms in youth with autism

OBJECTIVE

Evidence-based guidance of clinical decision-making for the management of Autism Spectrum Disorder (ASD) is lacking, particularly for co-occurring psychiatric symptoms. This review evaluates treatment evidence for six common symptom targets in children/adolescents with ASD and provides a resource to facilitate application of the evidence to clinical practice.

METHOD

A systematic search identified randomized controlled trials (RCTs) and high-quality systematic reviews published between 2007 and 2016, focused on: social interaction/communication impairment, stereotypic/repetitive behaviours, irritability/agitation, attention-deficit/hyperactivity disorder symptoms, mood or anxiety symptoms, and sleep difficulties. We then completed qualitative evaluation of high-quality systematic reviews/meta-analyses and quantitative evaluation of recently published RCTs not covered by prior comprehensive systematic reviews.

RESULTS

Recently published RCTs focused on social interaction and communication impairment (trials = 32) using psychosocial interventions. Interventions for irritability/agitation (trials = 16) were mainly pharmacological. Few RCTs focused on other symptom targets (trials = 2-5/target). Integration of these results with our qualitative review indicated that few established treatment modalities exist, and available evidence is limited by small studies with high risk of bias.

CONCLUSION

Given the current evidence-base, treatment targets must be clearly defined, and a systematic approach to intervention trials in children/adolescents with ASD must be undertaken with careful consideration of the limitations of safety/efficacy data.

Pharmacotherapy of emotional and behavioral symptoms associated with autism spectrum disorder in children and adolescents

Autism spectrum disorder (ASD) is characterized by impairment in social communication and restricted patterns of behavior. Although there is no pharmacological treatment approved by the US Food and Drug Administration (FDA) for the core symptoms of ASD, there is mounting support in the literature for the management of behavioral symptoms associated with this developmental disorder, in particular, irritability and hyperactivity. Aripiprazole and risperidone are currently approved by the FDA for the treatment of irritability in youth with ASD. Though not FDA-approved, methylphenidate and guanfacine are effective for the management of hyperactivity in children with ASD. Selective serotonin reuptake inhibitors are often used in clinical practice to target anxiety and compulsions; however, there is little evidence to support its use in this population. There is a great need for further research on the safety and efficacy of existing psychotropic medications in youth with ASD, as well as the development of new treatment modalities for the core and associated behavioral symptoms.

Buspirone in Children and Adolescents with Anxiety: A Review and Bayesian Analysis of Abandoned Randomized Controlled Trials

OBJECTIVES

An increasing number of abandoned clinical trials have forestalled efforts to advance the evidence base for the treatment of mood and anxiety disorders in children and adolescents. With this in mind, we sought to present and validate a Bayesian approach for the reanalysis of summary data in abandoned clinical trials and to review and re-evaluate available pharmacokinetic, tolerability, and efficacy data from two large, randomized controlled trials of buspirone in pediatric patients with generalized anxiety disorder (GAD).

METHODS

Prospective, randomized, parallel-group controlled trials of buspirone in pediatric patients with GAD as well as associated pharmacokinetic studies were identified and data were extracted. In addition to descriptive statistics, marginal posterior densities for each variable of interest were determined and a Monte Carlo pseudosample was generated with random draws obtained from the Student's t-distribution to assess, with inferential statistics, differences in variables of interest.

RESULTS

Buspirone was evaluated in one flexibly dosed (N = 227) and one fixed-dose (N = 341) trial in children and adolescents aged 6-17 years with a primary diagnosis of GAD. With regard to improvement in the sum of the Columbia Schedule for Affective Disorders and Schizophrenia GAD items, buspirone did not separate from placebo in the fixed-dose trial at low (95% CI: -0.78 to 2.39, p = 0.32) or high dose (95% CI: -0.87 to 1.87, p = 0.47) nor did it separate from placebo in the flexibly dosed study (95% CI: -0.3 to 1.9, p = 0.15). Drop out as a result of a treatment-emergent adverse event was significantly greater in buspirone-treated patients compared to placebo (p = 0.011). Side effects were consistent with the known profile of buspirone with lightheadedness occurring more frequently in buspirone-treated patients (p < 0.001).

CONCLUSIONS

Buspirone is well tolerated in pediatric patients with GAD, although two randomized controlled trials were underpowered to detect small effect sizes (Cohen's d < 0.15). Finally, Bayesian approaches may facilitate re-examination of data from abandoned clinical trials.

A Placebo-Controlled Crossover Trial of Gastrin-Releasing Peptide in Childhood Autism

OBJECTIVES

The aim of this study was to evaluate the efficacy, safety, and tolerability of gastrin-releasing peptide (GRP) compared with placebo in autism spectrum disorder symptoms.

METHODOLOGY

This is a randomized, double-blind, placebo-controlled crossover trial using GRP 160 pmol/kg for 4 consecutive days in 10 children with autism. Outcomes were measured by the Aberrant Behavior Checklist (ABC) scale.

RESULTS

All participants were boys, aged between 4 and 9 years. There was a reduction in the scores of the ABC range and its subscales after use GRP and placebo. The reduction was more prominent with GRP, particularly in the subscale "hyperactivity and noncompliance," but there was no statistical difference between the results (P = 0.334). After a week of infusion, 5 children showed improvement of 25% or greater in the total score of the ABC scale with GRP use and 2 with placebo use; however, there was no statistical difference (P = 0.375). There were no adverse effects, changes in vital signs, or laboratory abnormalities associated with the use of GRP.

CONCLUSIONS

The results of this study, despite the small sample size, reinforce previous data on the safety of the GRP in short-term use. There is a need for further research with other designs and a larger sample size to evaluate the efficacy and safety of GRP in children with autism.

Translational Mouse Models of Autism: Advancing Toward Pharmacological Therapeutics

Animal models provide preclinical tools to investigate the causal role of genetic mutations and environmental factors in the etiology of autism spectrum disorder (ASD). Knockout and humanized knock-in mice, and more recently knockout rats, have been generated for many of the de novo single gene mutations and copy number variants (CNVs) detected in ASD and comorbid neurodevelopmental disorders. Mouse models incorporating genetic and environmental manipulations have been employed for preclinical testing of hypothesis-driven pharmacological targets, to begin to develop treatments for the diagnostic and associated symptoms of autism. In this review, we summarize rodent behavioral assays relevant to the core features of autism, preclinical and clinical evaluations of pharmacological interventions, and strategies to improve the translational value of rodent models of autism.

An Orally Active Phenylaminotetralin-Chemotype Serotonin 5-HT7 and 5-HT1A Receptor Partial Agonist that Corrects Motor Stereotypy in Mouse Models

Stereotypy (e.g., repetitive hand waving) is a key phenotype of autism spectrum disorder, Fragile X and Rett syndromes, and other neuropsychiatric disorders, and its severity correlates with cognitive and attention deficits. There are no effective treatments, however, for stereotypy. Perturbation of serotonin (5-HT) neurotransmission contributes to stereotypy, suggesting that distinct 5-HT receptors may be pharmacotherapeutic targets to treat stereotypy and related neuropsychiatric symptoms. For example, preclinical studies indicate that 5-HT7 receptor activation corrects deficits in mouse models of Fragile X and Rett syndromes, and clinical trials for autism are underway with buspirone, a 5-HT1A partial agonist with relevant affinity at 5-HT7 receptors. Herein, we report the synthesis, in vitro molecular pharmacology, behavioral pharmacology, and pharmacokinetic parameters in mice after subcutaneous and oral administration of (+)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine ((+)-5-FPT), a new, dual partial agonist targeting both 5-HT7 (Ki = 5.8 nM, EC50 = 34 nM) and 5-HT1A (Ki = 22 nM, EC50 = 40 nM) receptors. Three unique, heterogeneous mouse models were used to assess the efficacy of (+)-5-FPT to reduce stereotypy: idiopathic jumping in C58/J mice, repetitive body rotations in C57BL/6J mice treated with the NMDA antagonist, MK-801, and repetitive head twitching in C57BL/6J mice treated with the 5-HT2 agonist, DOI. Systemic (+)-5-FPT potently and efficaciously reduced or eliminated stereotypy in each of the mouse models without altering locomotor behavior on its own, and additional tests showed that (+)-5-FPT, at the highest behaviorally active dose tested, enhanced social interaction and did not cause behaviors indicative of serotonin syndrome. These data suggest that (+)-5-FPT is a promising medication for treating stereotypy in psychiatric disorders.