The role of antipsychotics in the management of behavioural symptoms in children and adolescents with autism

Molecular Pathways, Neural Circuits and Emerging Therapies for Self-Injurious Behaviour

Nonsuicidal self-injurious behaviour (SIB) is a debilitating manifestation of physical aggression commonly observed across neurodevelopmental, psychiatric, and genetic disorders. This behaviour arises from a multifactorial aetiology involving genetic predispositions, epigenetic modifications, neurotransmitter dysregulation, and environmental stressors. Dysregulation in dopaminergic, serotonergic, glutamatergic, and GABAergic systems has been implicated in the pathophysiology of SIB, alongside structural and functional abnormalities within fronto-limbic-striatal circuits. These disruptions impair key processes, such as emotional regulation, reward processing, and behavioural inhibition, contributing to the emergence and reinforcement of SIB. Advances in preclinical research using genetic, lesion-based, pharmacological, and environmental animal models have been instrumental in elucidating the molecular and neurocircuitry underpinnings of SIB. Emerging neuromodulation therapies targeting critical nodes within the fronto-limbic-striatal network, particularly deep brain stimulation, have shown promise in treating severe, refractory SIB and improving quality of life. This review integrates current evidence from clinical studies, molecular research, and preclinical models to provide a comprehensive overview of the pathophysiology of SIB and therapeutic approaches. By focusing on the molecular mechanisms and neural circuits underlying SIB, we highlight the translational potential of emerging pharmacological and neuromodulatory therapies. A deeper understanding of these pathways will pave the way for precision-based interventions, bridging the gap between molecular research and clinical applications in SIB and related conditions.

Deep Brain Stimulation of the Nucleus Accumbens for Severe Self-Injurious Behavior in Children: A Phase I Pilot Trial

BACKGROUND

Self-injurious behavior (SIB) consists of repetitive, nonaccidental movements that result in physical damage inflicted upon oneself, without suicidal intent. SIB is prevalent among children with autism spectrum disorder and can lead to permanent disability or death. Neuromodulation at a locus of neural circuitry implicated in SIB, the nucleus accumbens (NAc), may directly influence these behaviors.

METHODS

We completed a phase I, open-label clinical trial of deep brain stimulation (DBS) of the NAc in children with severe, treatment-refractory SIB (ClinicalTrials.gov identifier NCT03982888). Participants were monitored for 12 months following NAc-DBS to assess the primary outcomes of safety and feasibility. Secondary outcomes included serial assessments of SIB and SIB-associated behaviors, ambulatory actigraphy, and changes in brain glucose metabolism induced by DBS.

RESULTS

Six children (ages 7-14 years) underwent NAc-DBS without serious adverse events. One child was found to have a delayed asymptomatic intracranial hemorrhage adjacent to a DBS electrode that did not require intervention, and 3 children experienced transient worsening in irritability or SIB with titration of stimulation parameters. NAc-DBS resulted in significant reductions in SIB and SIB-associated behaviors across multiple standardized scales, concurrent with clinically meaningful improvements in quality of life. Ambulatory actigraphy showed reductions in high-amplitude limb movements and positron emission tomography revealed treatment-induced reductions in metabolic activity within the thalamus, striatum, and temporoinsular cortex.

CONCLUSIONS

This first-in-children phase 1 clinical trial demonstrates the safety and feasibility of NAc-DBS in children with severe, refractory SIB at high risk of physical injury and death and supports further investigations.

Deep brain stimulation for autism spectrum disorder

Deep brain stimulation (DBS) is a medical treatment that aims to obtain therapeutic effects by applying chronic electrical impulses in specific brain structures and neurological circuits. Over the years, DBS has been studied for the treatment of many psychiatric disorders. Scientific research on the use of DBS in people with autism has focused this interest mainly on treatment-resistant obsessive-compulsive disorder, drug-resistant epilepsy, self-injurious behaviors (SIB), and aggressive behaviors toward the self. Autism spectrum disorder (ASD) includes a group of developmental disabilities characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills and the presence of repetitive and stereotyped behaviors as well as restricted interests. People with autism often have numerous medical and psychiatric comorbidities that worsen the quality of life of patients and their caregivers. Obsessive-compulsive symptoms can be found in up to 81.3% of people with autism. They are often severe, refractory to treatment, and particularly difficult to treat. SIB has a high prevalence in severely retarded individuals and is often associated with autism. Drug treatment of both autism and SIB presents a therapeutic challenge. To describe the current state of the art regarding the efficacy of DBS in people with ASD, a literature search was conducted for relevant studies using the PubMed database. Thirteen studies have been considered in this paper. Up to date, DBS has been used for the stimulation of the nucleus accumbens, globus pallidus internus, anterior limb of the internal capsule, ventral anterior limb of the internal capsule, basolateral amygdala, ventral capsule and ventral striatum, medial forebrain bundle, and posterior hypothalamus. In the total sample of 16 patients, 4 were adolescents, and 12 were adults. All patients had symptoms resistant to multiple drug therapy. Many patients taken into consideration by the studies showed clinical improvements as evidenced by the scores of the psychopathological scales used. In some cases, clinical improvements have varied over time, which may require further investigation. Among the new therapeutic perspectives, DBS could be a valid option. However, further, and more in-depth research is needed in this field.

Deep brain stimulation for extreme behaviors associated with autism spectrum disorder converges on a common pathway: a systematic review and connectomic analysis

OBJECTIVE

Individuals with autism spectrum disorder (ASD) may display extreme behaviors such as self-injury or aggression that often become refractory to psychopharmacology or behavioral intervention. Deep brain stimulation (DBS) is a surgical alternative that modulates brain circuits that have yet to be clearly elucidated. In the current study the authors performed a connectomic analysis to identify brain circuitry engaged by DBS for extreme behaviors associated with ASD.

METHODS

A systematic review was performed to identify prior reports of DBS as a treatment for extreme behaviors in patients with ASD. Individual patients' perioperative imaging was collected from corresponding authors. DBS electrode localization and volume of tissue activated modeling were performed. Volumes of tissue activated were used as seed points in high-resolution normative functional and structural imaging templates. The resulting individual functional and structural connectivity maps were pooled to identify networks and pathways that are commonly engaged by all targets.

RESULTS

Nine patients with ASD who were receiving DBS for symptoms of aggression or self-injurious behavior were identified. All patients had some clinical improvement with DBS. Connectomic analysis of 8 patients (from the systematic review and unpublished clinical data) demonstrated a common anatomical area of shared circuitry within the anterior limb of the internal capsule. Functional analysis of 4 patients identified a common network of distant brain areas including the amygdala, insula, and anterior cingulate engaged by DBS.

CONCLUSIONS

This study presents a comprehensive synopsis of the evidence for DBS in the treatment of extreme behaviors associated with ASD. Using network mapping, the authors identified key circuitry common to DBS targets.

An open-label prospective pilot trial of nucleus accumbens deep brain stimulation for children with autism spectrum disorder and severe, refractory self-injurious behavior: study protocol

BACKGROUND

Children and youth with autism spectrum disorder (ASD) may manifest self-injurious behaviors (SIB) that may become severe and refractory with limited pharmacologic or behavioral treatment options. Here, we present the protocol of a prospective, mixed-methods study to assess the safety and efficacy of deep brain stimulation (DBS) of the nucleus accumbens (NAcc) for children and youth with ASD and severe, refractory SIB.

METHODS

This is a prospective, single-center, single-cohort, open-label, non-randomized pilot trial of 6 patients. Participants will be recruited through specialized behavioral clinics with persistent severe and refractory SIB following standard and intensive interventions. Following NAcc-DBS, participants will be enrolled in the study for 12 months. The primary objectives of the study are safety and feasibility, assessed by rate of recruitment and identification of factors impacting adherence to follow-up and study protocol. Potential treatment efficacy will be assessed by changes in the Children's Yale-Brown Obsessive-Compulsive Scale in ASD (CYBOCS-ASD), the Behavior Problems Index (BPI), the Inventory of Statements about Self-Injury (ISAS) and the Repetitive Behavior Scale-Revised (RBS-R) questionnaires. Additional clinical outcomes will be assessed, including measures of participant and caregiver quality of life, actigraph measurements, and positron emission tomography (PET) changes following DBS.

DISCUSSION

This study will be the first to evaluate the effect of DBS of the NAcc on a pediatric population in a controlled, prospective trial. Secondary outcomes will improve the understanding of behavioral, neuro-imaging, and electrophysiologic changes in children with ASD and SIB treated with DBS. This trial will provide an estimated effect size of NAcc-DBS for severe refractory SIB in children with ASD in preparation for future comparative trials.

TRIAL REGISTRATION

Registration on ClinicalTrials.gov was completed on 12 June 2019 with the Identifier: NCT03982888 .

Neural Mechanisms Underlying Repetitive Behaviors in Rodent Models of Autism Spectrum Disorders

Autism spectrum disorder (ASD) is comprised of several conditions characterized by alterations in social interaction, communication, and repetitive behaviors. Genetic and environmental factors contribute to the heterogeneous development of ASD behaviors. Several rodent models display ASD-like phenotypes, including repetitive behaviors. In this review article, we discuss the potential neural mechanisms involved in repetitive behaviors in rodent models of ASD and related neuropsychiatric disorders. We review signaling pathways, neural circuits, and anatomical alterations in rodent models that display robust stereotypic behaviors. Understanding the mechanisms and circuit alterations underlying repetitive behaviors in rodent models of ASD will inform translational research and provide useful insight into therapeutic strategies for the treatment of repetitive behaviors in ASD and other neuropsychiatric disorders.

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.

Risperidone for children and adolescents with autism spectrum disorder: a systematic review

BACKGROUND

Various clinical trials suggested that risperidone was beneficial in the treatment of autism spectrum disorder (ASD) in children and adolescents.

OBJECTIVE

The aim of this systematic review was to determine the efficacy, acceptability and tolerability of risperidone in the treatment of children and adolescents with ASD.

DATA SOURCES

The databases of Scopus, PubMed, CINAHL and Cochrane Controlled Trials Register were searched in February 2017.

STUDY ELIGIBILITY CRITERIA PARTICIPANTS AND INTERVENTIONS

Eligible RCTs of risperidone in the treatment of child and adolescent patients with ASD. Languages were not restricted.

STUDY APPRAISAL AND SYNTHESIS METHODS

The full-text versions of relevant studies were thoroughly assessed and extracted. The primary efficacy of outcome was the pooled response rate and the pooled mean changed scores of the standardized rating scales for ASD.

RESULTS

A total of 372 randomized subjects from seven RCTs were included in this review. In acute treatment, the pooled mean change score of the Aberrant Behavior Checklist for irritability subscale (ABC-I) and response rate for the risperidone-treated group had a greater significance than that of the placebo-treated group. In the long-term treatment, the pooled mean change score of the CARS in the risperidone-treated group was significantly greater than that in the placebo-treated group. According to the discontinuation phase, the overall pooled relapse rate of the risperidone-treated group was significantly less than that of the placebo-treated group. The rates of pooled overall discontinuation and discontinuation due to adverse events rates were not different between the two groups in acute and long-term treatments.

LIMITATIONS

A small study was included in the current review.

CONCLUSION

In relation to the current systematic review, risperidone is efficacious in the treatment of symptoms in children and adolescents with ASD. Although its acceptability is comparable to placebo, treatment with risperidone is well tolerated in children and adolescents with ASD.

Impact of Dendrimers on Solubility of Hydrophobic Drug Molecules

Adequate aqueous solubility has been one of the desired properties while selecting drug molecules and other bio-actives for product development. Often solubility of a drug determines its pharmaceutical and therapeutic performance. Majority of newly synthesized drug molecules fail or are rejected during the early phases of drug discovery and development due to their limited solubility. Sufficient permeability, aqueous solubility and physicochemical stability of the drug are important for achieving adequate bioavailability and therapeutic outcome. A number of different approaches including co-solvency, micellar solubilization, micronization, pH adjustment, chemical modification, and solid dispersion have been explored toward improving the solubility of various poorly aqueous-soluble drugs. Dendrimers, a new class of polymers, possess great potential for drug solubility improvement, by virtue of their unique properties. These hyper-branched, mono-dispersed molecules have the distinct ability to bind the drug molecules on periphery as well as to encapsulate these molecules within the dendritic structure. There are numerous reported studies which have successfully used dendrimers to enhance the solubilization of poorly soluble drugs. These promising outcomes have encouraged the researchers to design, synthesize, and evaluate various dendritic polymers for their use in drug delivery and product development. This review will discuss the aspects and role of dendrimers in the solubility enhancement of poorly soluble drugs. The review will also highlight the important and relevant properties of dendrimers which contribute toward drug solubilization. Finally, hydrophobic drugs which have been explored for dendrimer assisted solubilization, and the current marketing status of dendrimers will be discussed.

Aripiprazole for the treatment of irritability and aggression in children and adolescents affected by autism spectrum disorders

INTRODUCTION

Aripiprazole is an atypical antipsychotic approved for the treatment of irritability and aggression in children and adolescents aged 6-17 years with autism spectrum disorder.

AREAS COVERED

This review will discuss the drug profile as well as available studies of aripiprazole in individuals with autism spectrum disorder as documented in prospective randomized controlled trials. Expert commentary: The heterogeneity of autism spectrum disorder has implications for assessing the effectiveness and safety of aripiprazole as it may not produce the same results in two individuals with the same diagnosis but different etiologies. Subgrouping of patients according to their overall presentation of symptoms may therefore be warranted. In addition, consideration should be given to the potential causes of irritability and aggression, such as coexisting medical conditions and environmental factors including inappropriate intervention of parents and teachers. In these cases, the identification of the underlying cause is important because the appropriate management.

The effects of long-term medication on growth in children and adolescents with ADHD: an observational study of a large cohort of real-life patients

BACKGROUND

Children and adolescents with ADHD treated with central stimulants (CS) often have growth deficits, but the implications of such treatment for final height and stature remain unclear.

METHODS

Weight and height were assessed multiple times in 410 children and adolescents during long-term treatment with CS, which lasted between 0.9 and 16.1 years. Weight and height measures were converted to z-scores based on age- and sex-adjusted population tables.

RESULTS

CS treatment was associated with (1) a relative reduction in body weight and a temporary halt in growth, (2) a weight and height lag after 72 months compared with relative baseline values. No relation to early start of medication (<6 years), gender, comorbid ODD/CD or emotional disorders was observed.

CONCLUSIONS

Treatment with central stimulants for ADHD impacts growth in children and adolescents, and growth should be continuously monitored in patients on chronic treatment with these medications.

Optimization and in vivo toxicity evaluation of G4.5 PAMAM dendrimer-risperidone complexes

Risperidone is an approved antipsychotic drug belonging to the chemical class of benzisoxazole. This drug has low solubility in aqueous medium and poor bioavailability due to extensive first-pass metabolism and high protein binding (>90%). Since new strategies to improve efficient treatments are needed, we studied the efficiency of anionic G4.5 PAMAM dendrimers as nanocarriers for this therapeutic drug. To this end, we explored dendrimer-risperidone complexation dependence on solvent concentration, pH and molar relationship. The best dendrimer-risperidone incorporation (46 risperidone molecules per dendrimer) was achieved with a mixture of chloroform:methanol 50∶50 v/v solution pH 3. In addition, to explore the possible effects of this complex, in vivo studies were carried out in the zebrafish model. Changes in the development of dopaminergic neurons and motoneurons were studied using tyrosine hydroxylase and calretinin, respectively. Physiological changes were studied through histological sections stained with hematoxylin-eosin to observe possible morphological brain changes. The most significant changes were observed when larvae were treated with free risperidone, and no changes were observed when larvae were treated with the complex.

What's in the pipeline? Drugs in development for autism spectrum disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with both core symptoms and associated symptoms (eg, irritability, aggression, and comorbidities) that affect both the individual and the family/systems around them. There have been recent advances in the understanding of the underlying pathophysiology of ASD pertaining to genetics, epigenetics, neurological, hormonal, and environmental factors that contribute to the difficulties found in individuals with ASD. With this improved understanding, there has been a shift in the application of psychopharmacology in ASD and its related disorders. A literature review was conducted to examine research published in the last 5 years between different classes of psychotropic medications and ASD. The broad scope of the existing literature for the use of conventional medications is summarized and novel medications are discussed.

Safety and tolerability of aripiprazole in the treatment of irritability associated with autistic disorder in pediatric subjects (6-17 years old):results from a pooled analysis of 2 studies

BACKGROUND

With increasing use of atypical antipsychotics among pediatric patients, detailed information about safety and tolerability is crucial.

METHOD

Data were pooled from two 8-week, randomized, double-blind, multicenter, parallel-group trials comparing aripiprazole versus placebo in subjects aged 6 to 17 years with irritability associated with DSM-IV-TR-diagnosed autistic disorder: one flexibly dosed (aripiprazole 2-15 mg/d; target of 5, 10, or 15 mg/d), the other fixed-dose (aripiprazole 5, 10, or 15 mg/d). The first was conducted from June 2006-April 2008, and the second, from June 2006-June 2008. Adverse events were characterized with respect to incidence, duration, severity, timing of peak incidence of onset, and dose-response relationship. Extrapyramidal symptoms, drooling, and metabolic parameters were evaluated.

RESULTS

Three hundred thirteen subjects comprised the safety sample (aripiprazole 212, placebo 101). Discontinuations due to adverse events with aripiprazole versus placebo were, overall, 10.4% versus 6.9%; subjects 6-12 years: 10.8% versus 5.1%; and subjects 13-17 years: 8.9% versus 13.6%. Common adverse events with aripiprazole versus placebo included sedation (20.8% vs 4.0%), fatigue (16.5% vs 2.0%), vomiting (13.7% vs 6.9%), increased appetite (12.7% vs 6.9%), somnolence (10.4% vs 4.0%), and tremor (9.9% vs 0.0%). Most adverse events were mild or moderate and occurred early. Only fatigue showed a dose-response relationship (P < .05). Mean body weight change (last observation carried forward, 1.6 vs 0.4 kg) was higher with aripiprazole than placebo (P < .001). There were no between-treatment differences in metabolic changes. The extrapyramidal symptom-related adverse event incidence with aripiprazole versus placebo was, overall, 20.8% vs 9.9%; the incidence of akathisia-related events was 3.3% vs 8.9%.

CONCLUSIONS

Aripiprazole was generally safe and well tolerated in subjects (6-17 years) with irritability associated with autistic disorder in these 8-week studies; clinicians should be aware of this clinical profile and strategies to manage adverse events if they occur.

TRIAL REGISTRATION

clinicaltrials.gov Identifiers NCT00332241 and NCT00337571.

Aripiprazole in the treatment of challenging behaviour in adults with autism spectrum disorder

BACKGROUND

Autism spectrum disorders (ASD) are associated with repetitive behaviours and often also with hyperactivity, aggression, self-injurious behaviour, irritability and lability of mood. There is emerging evidence that aripiprazole, an antipsychotic with partial agonist dopaminergic effect, may be effective in the treatment of these challenging behaviours. Nevertheless, there is little evidence for their efficacy in adults with ASD.

OBJECTIVES

The aim of this article is to present preliminary data on the use of aripiprazole in the treatment of challenging behaviour in the setting of ASD.

METHODS

We present a consecutive series of five inpatients of normal intelligence with challenging behaviour associated with ASD, diagnosed according to ICD-10 criteria, which was resistant to treatment with other medical and behavioural interventions and which was treated with aripiprazole.

RESULTS

Four out of five patients were classified as "much improved" or "very much improved" according to the Clinical Global Impression-Improvement scale. Aripiprazole caused akathisia, at a dose of 30 mg in the one patient who was not classified as a responder but was otherwise well tolerated.

CONCLUSIONS

This is the first case series of adults with ASD presenting with challenging behaviour who have been treated with aripiprazole. While the results are promising, controlled trials are required to confirm the findings.

Overuse of psychotropic medications among children and adolescents with autism spectrum disorders: perspective from a developing country

Psychopharmacotherapy can be an effective part of the treatment for individuals with autism spectrum disorders (ASDs). However debate continues over the potential benefits and costs of these treatments; additionally little is known about the pattern of psychotropic medication use in developing countries. We aimed to survey the use of psychotropic medication, their subcategories and its associations among a representative local sample of 345 Iranian pupils with ASDs. All required information about demographics as well as clinical and medication history of children was collected through interviews with the families. Overall, 80% of participants were currently using at least one psychotropic medication while, and up to 97% of the sample had at least one psychotropic medication claim during the last year. Antipsychotics were the most frequent medications (57.4%) while antidepressants were used by only a small proportion of participants (8.7%). Further analysis revealed no significant association between any psychotropic medication use on one hand and clinical and demographic characteristics on the other hand. Time differences, cross cultural variations, and also cost and availability of treatment options in developing countries are discussed as possible explanations for different patterns and more than expected rate of psychotropic medication use in pupils with ASD.

Ten years of antipsychotic prescribing to children: a Canadian population-based study

OBJECTIVE

To report the prescribing of antipsychotics to the youth population of the Canadian province of Manitoba during the course of a decade.

METHODS

Use of antipsychotics in children and adolescents (aged 18 years or younger) was described using data collected from the administrative health databases of Manitoba Health and the Statistics Canada census between the fiscal years of 1999 and 2008.

RESULTS

The prevalence of antipsychotic use in this segment of the population increased with the introduction of the second-generation antipsychotics (SGAs) from 1.9 per 1000 in 1999 to 7.4 per 1000 in 2008. The male-to-female antipsychotic usage ratio increased from 1.9 to 2.7 as the male youth population represented the fastest-growing subgroup of antipsychotic users in the entire population of Manitoba. The total number of prescriptions also increased significantly despite the lack of approved indications in this population. Proportion of use remained equally split between high- and low-income users. More than 70% of antipsychotic prescriptions to children and adolescents were written by general practitioners. The most common diagnoses linked to antipsychotic use were attention-deficit hyperactivity disorder and conduct disorders. Use of antipsychotics in combination with methylphenidate increased from 13% to 43%.

CONCLUSION

Extensive off-label use of SGAs has been observed in the youth population of Manitoba for treatment of aggressive behaviours across a range of diagnoses. It is important to monitor antipsychotic prescribing to children as more reports of significant adverse events associated with antipsychotics become available.

A dental look at the autistic patient through orofacial pain

Abstract Autism is a neurodevelopmental disorder characterized by impaired social interaction and restricted interests, compromised communication skills, and repetitive patterns of behavior. Both social and behavioral problems, which may include hyperactivity and quick frustration, may hinder the detection of other important pathologies such as orofacial pain. This is aggravated by the invasive nature of oral exploration, which may trigger violent and self-injurious responses, such as temper tantrums and/or head banging, which make the work of professionals extremely difficult during diagnoses, follow-up examinations, and dental treatments. In addition, mercury-containing amalgams used to treat dental caries (the most common form of acute orofacial pain) have been associated with higher rates of severe autism in children. The purpose of this review is to describe the current state of the art regarding the co-occurrence of orofacial pain and autism spectrum disorder, and how these conditions may interrelate clinically and neurobiologically.

Aripiprazole: in the treatment of irritability associated with autistic disorder in pediatric patients

Aripiprazole is an atypical antipsychotic approved for the treatment of irritability associated with autistic disorder in pediatric patients aged 6-17 years. In two, randomized, double-blind, placebo-controlled studies in pediatric patients aged 6-17 years with irritability associated with autistic disorder, 8 weeks of treatment with aripiprazole 2-15 mg/day, compared with placebo, resulted in significant improvements in the Aberrant Behavior Checklist Irritability subscale score at endpoint (primary endpoint), and the mean Clinical Global Impression-Improvement score. Aripiprazole was generally well tolerated in this patient population in the two 8-week studies and a 52-week study, with most adverse events being mild to moderate in severity. Aripiprazole was associated with weight gain in both the short- and long-term studies; data from the long-term study indicated that the increase in bodyweight reached a plateau at 3-6 months.

Optimization and in vitro toxicity evaluation of G4 PAMAM dendrimer-risperidone complexes

Risperidone is an approved antipsychotic drug belonging to the chemical class of benzisoxazole. This drug has low solubility in aqueous medium and poor bioavailability due to extensive first-pass metabolism and high protein binding (>90%). As new strategies to improve treatments efficiency are needed, we have studied cationic G4 PAMAM dendrimers' performance to act as efficient nanocarriers for this therapeutic drug. In this respect, we explored dendrimer-risperidone complexation dependence on solvent, temperature, pH and salt concentration, as well as in vitro cytotoxicity measured on L929 cell line and human red blood cells. The best dendrimer-risperidone incorporation was achieved when a mixture of 70:30 and 90:10 v/v chloroform:methanol was used, obtaining 17 and 32 risperidone molecules per dendrimer, respectively. No cytotoxicity on L929 cells was found when dendrimer concentration was below 3 × 10(-2) μM and risperidone concentration below 5.1 μM. Also, no significant hemolysis or morphological changes were observed on human red blood cells. Finally, attempting to obtain an efficient drug delivery system for risperidone, incorporation in G4 PAMAM dendrimers was optimized, improving drug solubility with low cytotoxicity.

Emerging role of aripiprazole for treatment of irritability associated with autistic disorder in children and adolescents

Autistic disorder is a largely misunderstood and difficult to treat neurodevelopmental disorder. Three core domains of functioning are affected by autistic disorder, ie, socialization, communication, and behavior. Signs of autistic disorder may be present early, but are frequently overlooked, resulting in a delay in its diagnosis and a subsequent delay in treatment. No one definitive therapy is available, and treatment consists of early educational and behavioral interventions, as well as drug therapy. Atypical antipsychotics have often been used in the treatment of autistic disorder to target irritability, aggression, and self-injurious behavior, all of which can interfere with other aspects of treatment. One atypical antipsychotic, aripiprazole, has recently been approved for treatment of irritability associated with autistic disorder. Based on the results from two randomized, controlled trials, with efficacy data from nearly 300 patients, treatment with aripiprazole was associated with reductions in irritability, global improvements in behavior, and improvements in quality of life from both the patient and caregiver perspectives. Dosage of aripiprazole ranged from 5 mg to 15 mg per day. Aripiprazole was well tolerated during clinical trials, with most adverse events considered mild or moderate. Clinically relevant weight gain occurred in about 30% of patients given aripiprazole, although when compared with other atypical antipsychotics, aripiprazole appears to have fewer metabolic effects and a lower risk of weight gain. However, pediatric patients taking any atypical antipsychotic should be carefully monitored for potential adverse events, because the long-term effects of antipsychotic therapy in this population are not well known. When used appropriately, aripiprazole has the potential to be an effective treatment for children with autistic disorder to improve irritability and aggressive behavior and improve quality of life.