Bio-behavioral model of aggression in autism spectrum disorders-pilot study

Children with autism spectrum disorders (ASD) have a high rate of irritability and aggressive symptoms which have significant impact on their lives, families and society. The etiology of aggression in humans is likely complex and includes both biological and behavioral causes. Biological approaches have focused on hormones and neurotransmitters that are hypothesized to contribute to the etiology and clinical manifestation of aggressive behavior in humans. Testosterone is a male sex hormone and some studies suggest that it can play a role in the complex etiology of aggressive behavior. Two specific subtypes of aggression have been identified: explosive and non-explosive. Explosive aggression is accompanied by a raged affect and is usually more dangerous and not immediately responsive to behavioral treatment. We propose that individuals with ASD and explosive aggression will have higher androgen activity and higher arousal than neurotypical children and children with ASD without explosive aggression. We employed a unique method for aggression assessment- functional behavioral analysis- to obtain objective and quantitative measures of aggression and arousal signs. In our pilot study, we proposed to determine bio-behavioral model of explosive aggression in children with ASD which will predict which children will be most responsive to antiandrogen therapy and behavioral therapy (Tab. 1, Fig. 1, Ref. 31).

Plasma Oxytocin in Children with Autism and Its Correlations with Behavioral Parameters in Children and Parents

OBJECTIVE

Oxytocin (OT) has been implicated to play an important role in autism spectrum disorders (ASD) etiology. We aimed to find out the differences in plasma OT levels between children with autism and healthy children, the associations of OT levels with particular autism symptoms and the associations of particular parental autistic traits with their ASD children OT levels.

METHODS

We included 19 boys with autism and 44 healthy age-matched boys. OT levels were analyzed by ELISA method. Children with autism were scored by Childhood Autism Rating Scale and Autism Diagnostic Interview (ADI), adjusted research version. Autism Spectrum Quotient (AQ), Systemizing Quotient (SQ) and Empathizing Quotient were completed by parents of children with autism.

RESULTS

Children with autism had significantly lower plasma OT levels than controls. OT levels positively correlated with ADI Reciprocal Interaction and Communication scores. AQ and SQ of fathers positively correlated with children plasma OT level.

CONCLUSION

Our results support the hypothesis of OT deficiency in autism. The "paradoxical" associations of OT levels and social skills in children with autism indicate disturbances at various levels of OT system. We first reported associations of OT levels in children with autism and behavioral measures in fathers indicating that OT abnormalities stay between parental autistic traits and autism symptoms in their children.

Testosterone and Androgen Receptor Sensitivity in Relation to Hyperactivity Symptoms in Boys with Autism Spectrum Disorders

INTRODUCTION

Autism spectrum disorders (ASD) and hyperactivity symptoms exhibit an incidence that is male-biased. Thus androgen activity can be considered a plausible biological risk factor for these disorders. However, there is insufficient information about the association between increased androgen activity and hyperactivity symptoms in children with ASD.

METHODS

In the present study, the relationship between parameters of androgenicity (plasmatic testosterone levels and androgen receptor sensitivity) and hyperactivity in 60 boys (age 3-15) with ASD is investigated. Given well documented differences in parent and trained examiners ratings of symptom severity, we employed a standardized parent`s questionnaire (Nisonger Child Behavior Rating Form) as well as a direct examiner`s rating (Autism diagnostic observation schedule) for assessment of hyperactivity symptoms.

RESULTS

Although it was found there was no significant association between actual plasmatic testosterone levels and hyperactivity symptoms, the number of CAG triplets was significantly negatively correlated with hyperactivity symptoms (R2 = 0.118, p = 0.007) in the sample, indicating increased androgen receptor sensitivity in association with hyperactivity symptoms. Direct trained examiner´s assessment appeared to be a relevant method for evaluating of behavioral problems in the investigation of biological underpinnings of these problems in our study.

CONCLUSIONS

A potential ASD subtype characterized by increased rates of hyperactivity symptoms might have distinct etiopathogenesis and require a specific behavioral and pharmacological approach. We propose an increase of androgen receptor sensitivity as a biomarker for a specific ASD subtype accompanied with hyperactivity symptoms. Findings are discussed in terms of their implications for practice and future research.

Testosterone in relation to behavioral problems in pre-pubertal boys with autism spectrum disorders

Autism spectrum disorders (ASD) are neurodevelopmental conditions characterized by impairment in social communication and presence of stereotyped/restricted behaviors. Children with ASD very often demonstrate co-morbid psychiatric problems, problems known to be affected by testosterone in neurotypical populations. However, there are few reports investigating relationships between testosterone and psychiatric conditions in children with ASD. The aim of this study was to determine the relationship between plasmatic levels of testosterone and behavioral/emotional problems in pre-pubertal boys with ASD. The study sample consisted of 31 pre-pubertal boys (ages 3-10) with ASD. Parents completed the Nisonger Child Behavior Rating Form (NCBRF) to assess specific behavioral/emotional problems as observed in the previous 2 months. Plasmatic testosterone levels were determined in boys according to standardized procedures. It was found that there were positive correlations between testosterone levels and the conduct problems subscale (p=0.034, rs=0.382) of NCBRF and also between testosterone levels and the hyperactive subscale (p=0.025, rs=0.402) of NCBRF. Findings in this study are in line with research conducted in the neurotypical population. This is the first large study investigating testosterone and emotional/behavioral problems in ASD and warrants further research in this field in order to clarify the etiopathogenesis of psychiatric co-morbidities and improve their treatment.

Testosterone and explosive aggression in autism spectrum disorders

Autism spectrum disorders (ASD) are a set of heterogeneous neurodevelopmental conditions, characterized by early-onset difficulties in social communication and unusually restricted, repetitive behavior and interests. Children with ASD have a high rate of irritability and aggressive symptoms which have significant impact on their lives, families and society. The etiology of aggression in humans is likely complex and includes both biological and behavioral causes. Biological approaches have focused on hormones and neurotransmitters that are hypothesized to contribute to the etiology and clinical manifestation of aggressive behavior in humans. Testosterone is a male sex hormone and some studies suggest that it can play a role in the complex etiology of aggressive behavior. Two specific subtypes of aggression have been identified: explosive and non-explosive. Explosive aggression is accompanied by a raged affect and is usually more dangerous and not immediately responsive to behavioral treatment. In our review we would like to provide current findings and discuss potential limitation of research in this area. We propose to determine bio-behavioral model of explosive aggression in children with ASD which will predict which children will be most responsive to potential antiandrogen therapy and behavioral therapy.