Randomised controlled trials of mood stabilisers for people with autism spectrum disorder: systematic review and meta-analysis

Cannabinoid treatment for the symptoms of autism spectrum disorder

INTRODUCTION

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting approximately 3% of school-age children. The core symptoms are deficits in social communication and restricted and repetitive patterns of behavior. Associated problems in cognition, language, behavior, sleep and mood are prevalent. Currently, no established pharmacological treatment exists for core ASD symptoms. Risperidone and aripiprazole are used to manage associated irritability, but their effectiveness is limited and adverse events are common.

AREAS COVERED

This mini-review summarizes existing scientific literature and ongoing clinical trials concerning cannabinoid treatment for ASD. Uncontrolled case series have documented improvements in both core ASD symptoms and related behavioral challenges in children treated with cannabis extracts rich in cannabidiol (CBD). Placebo-controlled studies involving CBD-rich cannabis extracts and/or pure CBD in children with ASD have demonstrated mixed efficacy results. A similar outcome was observed in a placebo-controlled study of pure CBD addressing social avoidance in Fragile X syndrome. Importantly, these studies have shown relatively high safety and tolerability.

EXPERT OPINION

While current clinical data suggest the potential of CBD and CBD-rich cannabis extract in managing core and behavioral deficits in ASD, it is prudent to await the results of ongoing placebo-controlled trials before considering CBD treatment for ASD.

Randomised controlled trials of antipsychotics for people with autism spectrum disorder: a systematic review and a meta-analysis

BACKGROUND

Despite unclear evidence to support the long-term use of antipsychotics to treat challenging (problem) behaviours in people with autism in the absence of a psychiatric disorder, this practice is common.

METHODS

We conducted a systematic review and meta-analysis of all randomised controlled trials (RCTs) involving antipsychotics for people with autism of all ages, irrespective of the outcomes assessed. We searched seven databases and hand-searched ten relevant journals. Two authors independently screened titles, abstracts and full papers and extracted data using the Cochrane Handbook template. We conducted meta-analyses of outcomes and the rate of adverse events.

RESULTS

We included 39 papers based on 21 primary RCTs that recruited 1482 people with autism. No RCT assessed any psychiatric disorder outcome, such as psychoses or bipolar disorder. A meta-analysis of ten placebo-controlled RCTs showed a significantly improved Aberrant Behaviour Checklist-Irritability score in the antipsychotic group with an effect size of -6.45 [95% confidence interval (CI) -8.13 to -4.77] (low certainty). Pooled Clinical Global Impression data on 11 placebo-controlled RCTs showed an overall effect size of 0.84 (95% CI 0.48 to 1.21) (moderate certainty). There was a significantly higher risk of overall adverse effects (p = 0.003) and also weight gain (p < 0.00001), sedation (p < 0.00001) and increased appetite (p = 0.001) in the antipsychotic group.

CONCLUSIONS

There is some evidence for risperidone and preliminary evidence for aripiprazole to significantly improve scores on some outcome measures among children with autism but not adults or for any other antipsychotics. There is a definite increased risk of antipsychotic-related different adverse effects.

A review of the use of psychotropic medication to address challenging behaviour in neurodevelopmental disorders

Engagement in challenging behaviour (e.g., aggression, self-injury) is reported to occur in neurodevelopmental disorders such as intellectual disabilities (ID), autism spectrum disorder (ASD), and fragile X syndrome (FXS). Common interventions to address these behaviours include both behavioural and pharmacological approaches. Although psychotropic medications are commonly used to address challenging behaviour in ID, ASD, and FXS, demonstration of the effectiveness of treatment is limited. Furthermore, research examining interaction effects between psychotropic medication, challenging behaviour, and environmental events within specific neurodevelopmental disorders such as ID, ASD, and FXS is scarce. The purpose of this chapter is to provide an overview of challenging behaviour within ID, ASD, and FXS and of the effectiveness of psychotropic medication as an intervention for challenging behaviour within these neurodevelopmental disorders. Finally, research examining how psychotropic medication may impact the relationship between challenging behaviour and environmental events is reviewed.

Acetylcholinesterase inhibitors for autistic spectrum disorders

BACKGROUND

Autism spectrum disorder (autism) is a neurodevelopmental condition characterised by impairments in social communication and interaction, plus restricted, repetitive patterns of behaviour and interests. Whilst some people embrace autism as part of their identity, others struggle with their difficulties, and some seek treatment. There are no current interventions that result in complete reduction of autism features. Acetylcholine is a neurotransmitter for the cholinergic system and has a role in attention, novelty seeking, and memory. Low levels of acetylcholine have been investigated as a potential contributor to autism symptomatology. Donepezil, galantamine, and rivastigmine (commonly referred to as acetylcholinesterase inhibitors) all inhibit acetylcholinesterase, and have slightly different modes of action and biological availability, so their effectiveness and side-effect profiles may vary. The effect of various acetylcholinesterase inhibitor on core autism features across the lifespan, and possible adverse effects, have not been thoroughly investigated.

OBJECTIVES

To evaluate the efficacy and harms of acetylcholinesterase inhibitors for people with the core features (social interaction, communication, and restrictive and repetitive behaviours) of autism. To assess the effects of acetylcholinesterase inhibitors on non-core features of autism.

SEARCH METHODS

In November 2022, we searched CENTRAL, MEDLINE, Embase, eight other databases, and two trials registers. We also searched the reference lists of included studies and relevant reviews, and contacted authors of relevant studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), comparing acetylcholinesterase inhibitors (e.g. galantamine, donepezil, or rivastigmine) of varying doses, delivered orally or via transdermal patch, either as monotherapy or adjunct therapy, with placebo. People of any age, with a clinical diagnosis of autism were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were core features of autism and adverse effects. Secondary outcomes were language, irritability, hyperactivity, and general health and function. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included two RCTs (74 participants). One study was conducted in Iran, the second in the USA, although exact location in the USA is unclear. Galantamine plus risperidone versus placebo plus risperidone One study compared the effects of galantamine plus risperidone to placebo plus risperidone (40 participants, aged 4 years to 12 years). Primary and secondary outcomes of interest were measured postintervention, using subscales of the Aberrant Behavior Checklist (score 0 to 3; higher scores = greater impairment). Very low-certainty evidence showed there was little to no difference between the two groups postintervention for social communication (mean difference (MD) -2.75, 95% confidence interval (CI) -5.88 to 0.38), and restricted and repetitive behaviour (MD -0.55, 95% CI -3.47 to 2.37). Overall autism features were not assessed. Adverse events may be higher in the galantamine plus risperidone group (75%) compared with the placebo plus risperidone group (35%): odds ratio 5.57, 95% CI 1.42 to 21.86, low-certainty evidence. No serious adverse events were reported. Low-certainty evidence showed a small difference in irritability (MD -3.50, 95% CI -6.39 to -0.61), with the galantamine plus risperidone group showing a greater decline on the irritability subscale than the placebo group postintervention. There was no evidence of a difference between the groups in hyperactivity postintervention (MD -5.20, 95% CI -10.51 to 0.11). General health and function were not assessed. Donepezil versus placebo One study compared donepezil to placebo (34 participants aged 8 years to 17 years). Primary outcomes of interest were measured postintervention, using subscales of the Modified Version of The Real Life Rating Scale (scored 0 to 3; higher scores = greater impairment). Very low-certainty evidence showed no evidence of group differences immediately postintervention in overall autism features (MD 0.07, 95% CI -0.19 to 0.33), or in the autism symptom domains of social communication (MD -0.02, 95% CI -0.34 to 0.30), and restricted and repetitive behaviours (MD 0.04, 95% CI -0.27 to 0.35). Significant adverse events leading to study withdrawal in at least one participant was implied in the data analysis section, but not explicitly reported. The evidence is very uncertain about the effect of donepezil, compared to placebo, on the secondary outcomes of interest, including irritability (MD 1.08, 95% CI -0.41 to 2.57), hyperactivity (MD 2.60, 95% CI 0.50 to 4.70), and general health and function (MD 0.03, 95% CI -0.48 to 0.54) postintervention. Across all analyses within this comparison, we judged the evidence to be very low-certainty due to high risk of bias, and very serious imprecision (results based on one small study with wide confidence intervals). The study narratively reported adverse events for the study as a whole, rather than by treatment group.

AUTHORS' CONCLUSIONS

Evidence about the effectiveness of acetylcholinesterase inhibitors as a medication to improve outcomes for autistic adults is lacking, and for autistic children is very uncertain. There is a need for more evidence of improvement in outcomes of relevance to clinical care, autistic people, and their families. There are a number of ongoing studies involving acetylcholinesterase inhibitors, and future updates of this review may add to the current evidence.

Mediators of Placebo Response to Cannabinoid Treatment in Children with Autism Spectrum Disorder

The placebo response has a substantial impact on treatment outcome. However, data regarding mediators of the placebo response in children with autism spectrum disorder (ASD) are sparse. This retrospective study investigated possible mediators of the placebo response among participants of a placebo-controlled trial of cannabinoid treatment for behavioral problems in children with ASD (CBA trial, age 5-21 years). We used a specifically designed questionnaire to explore possible mediators of the placebo response in 88 participants of the CBA trial who received a placebo and had valid outcome scores. The parents of 67 participants completed the questionnaire. The placebo response was positively associated with the child's comprehension of the treatment purpose (p = 0.037). There was also a trend for participants who had a relative aggravation of symptoms before treatment onset to improve following placebo treatment (p = 0.053). No other domains, including parental expectations, previous positive experience with similar treatments (behavioral conditioning), parental locus of control, quality of the patient-physician relationships, and adherence to study medications were associated with placebo-response. This finding suggests that efforts to explain the treatment purpose to children with disabilities may enhance treatment efficacy in clinical practice and decrease differences in the placebo response between study arms. Contrary to our hypothesis, parental expectations regarding cannabinoid treatment were not associated with the placebo response.

Pharmacological management of psychopathology in people with intellectual disabilities and/or autism spectrum disorder

On average, 49–63% of people with intellectual disabilities and/or autism spectrum disorder (ASD) are prescribed psychotropic medications to treat psychopathology, including psychiatric illness, behaviours that challenge and the core symptoms and associated behaviours of these developmental disorders. In many cases, psychotropics, particularly antipsychotics, are used off-label without a proper indication, particularly to manage behaviours that challenge. The RCTs show moderate evidence supporting the efficacy of low-dose risperidone and some preliminary evidence for aripiprazole in treating behaviours that challenge among children with ASD and/or intellectual disabilities. The RCT-based evidence for the other psychotropics is equivocal, so no definitive conclusions can be made on their efficacy. Polypharmacy and the use of high doses of antipsychotics are prevalent in this population, leading to the risk of adverse events and drug–drug interactions. Despite various national and international guidelines, and government initiatives encouraging reduced psychotropic use, there is little evidence of this happening; on the contrary, the use of antidepressants, mood stabilisers and benzodiazepines may be increasing. A concerted multi-agency effort is urgently needed to address this significant public health concern of the overmedication of people with intellectual disabilities and/or ASD.