Brief Report: Intranasal Ketamine in Adolescents and Young Adults with Autism Spectrum Disorder—Initial Results of a Randomized, Controlled, Crossover, Pilot Study

Esketamine Nasal Spray in Major Depressive Disorder: A Meta-Analysis of Randomized Controlled Trials

Despite being approved by the US FDA and the EU European Medicines Agency, the performance of esketamine nasal spray as an adjunctive therapy with an antidepressant in major depressive disorder is still controversial. Comprehensive retrieval in Embase, Pubmed, and Web of Science was conducted to identify randomized controlled trials comparing esketamine nasal spray versus control in major depressive disorder or treatment-resistant depression. The primary efficacy outcome was a reduction of the Montgomery-Asberg Depression Rating Scale, from baseline to Day 2 or Day 28 for patients with or without suicidal ideation, respectively. The long-term efficacy outcome was the relapse rate of patients who achieved stable remission. The certainty of evidence was assessed according to the Cochrane recommendation. Esketamine nasal spray was superior to placebo in reduction of Montgomery-Asberg Depression Rating Scale from baseline to Day 28 in patients without suicidal ideation (standardized mean difference: -0.24, 95% confidence interval: -0.38, -0.09, P = 0.001, I2 = 24%), and on Day 2 in patients with suicidal ideation (standardized mean difference: -0.30, 95% confidence interval: -0.47, -0.12, P = 0.0008, I2 = 0%). The long-term relapse rate was significantly lower in the esketamine nasal spray group than in the placebo/quetiapine group (risk ratio: RR: 0.60, 95% confidence interval: 0.45-0.80, I2 = 0%). The rate of suicidal ideation was similar between the two groups. The certainty of evidence was graded as "moderate" or "high" in the abovementioned results. Esketamine nasal spray in conjunction with an antidepressant effectively controls short-term and long-term depressive symptoms in major depressive disorder and treatment-resistant depression, with a manageable trade-off between efficacy and safety.

Challenges and hopes for treatment of anxiety disorder in the autistic population

Anxiety disorders, marked by excessive fear and worry, are particularly prevalent in autism, affecting up to 45 % of individuals with the condition. Since the 1960s, advances in neuroscience, psychology, and psychopharmacology have enhanced understanding and treatment of anxiety disorders in general population. Standardized diagnostic criteria development facilitated accurate classification of anxiety disorders. Neurobiological research identified key brain regions forming the basis of the amygdala-centred fear circuit model. Pharmacological advancements introduced selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) as safer, first-line treatments. However, these medications show limited efficacy and significant side effects in autistic individuals, highlighting the need for alternative treatments. Cognitive-behavioural therapy (CBT) has gained empirical support, helping to reduce avoidance behaviours, but modifications are often needed for autistic individuals. Emerging therapies, including Mindfulness-Based Stress Reduction for Autism Spectrum Disorder (MASSI) and virtual reality-based interventions, are being explored for individuals with more treatment-resistant anxiety. Ongoing clinical trials are assessing medications used for other psychiatric disorders to determine their efficacy in anxiety treatment for autism. Recent genetic and neuroimaging research has revealed altered brain connectivity and genetic susceptibility in anxiety, promoting the development of personalized treatments. Despite these advances, challenges remain in optimizing interventions and addressing treatment resistance, necessitating continued research and innovation.

Local activity alterations in autism spectrum disorder correlate with neurotransmitter properties and ketamine induced brain changes

Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with altered resting-state brain function. An increased excitation-inhibition (E/I) ratio is discussed as a potential pathomechanism but in-vivo evidence of disturbed neurotransmission underlying these functional alterations remains scarce. We compared rs-fMRI local activity (LCOR) between ASD (N=405, N=395) and neurotypical controls (N=473, N=474) in two independent cohorts (ABIDE1 and ABIDE2). We then tested how these LCOR alterations co-localize with specific neurotransmitter systems derived from nuclear imaging and compared them with E/I changes induced by GABAergic (midazolam) and glutamatergic medication (ketamine). Across both cohorts, ASD subjects consistently exhibited reduced LCOR, particularly in higher-order default mode network nodes, alongside increases in bilateral temporal regions, the cerebellum, and brainstem. These LCOR alterations negatively co-localized with dopaminergic (D1, D2, DAT), glutamatergic (NMDA, mGluR5), GABAergic (GABAa) and cholinergic neurotransmission (VAChT). The NMDA-antagonist ketamine, but not GABAa-potentiator midazolam, induced LCOR changes which co-localize with D1, NMDA and GABAa receptors, thereby resembling alterations observed in ASD. We find consistent local activity alterations in ASD to be spatially associated with several major neurotransmitter systems. NMDA-antagonist ketamine induced neurochemical changes similar to ASD-related alterations, supporting the notion that pharmacological modulation of the E/I balance in healthy individuals can induce ASD-like functional brain changes. These findings provide novel insights into neurophysiological mechanisms underlying ASD.

Glutamate-Mediated Excitotoxicity in the Pathogenesis and Treatment of Neurodevelopmental and Adult Mental Disorders

Glutamate is the main excitatory neurotransmitter in the brain wherein it controls cognitive functional domains and mood. Indeed, brain areas involved in memory formation and consolidation as well as in fear and emotional processing, such as the hippocampus, prefrontal cortex, and amygdala, are predominantly glutamatergic. To ensure the physiological activity of the brain, glutamatergic transmission is finely tuned at synaptic sites. Disruption of the mechanisms responsible for glutamate homeostasis may result in the accumulation of excessive glutamate levels, which in turn leads to increased calcium levels, mitochondrial abnormalities, oxidative stress, and eventually cell atrophy and death. This condition is known as glutamate-induced excitotoxicity and is considered as a pathogenic mechanism in several diseases of the central nervous system, including neurodevelopmental, substance abuse, and psychiatric disorders. On the other hand, these disorders share neuroplasticity impairments in glutamatergic brain areas, which are accompanied by structural remodeling of glutamatergic neurons. In the current narrative review, we will summarize the role of glutamate-induced excitotoxicity in both the pathophysiology and therapeutic interventions of neurodevelopmental and adult mental diseases with a focus on autism spectrum disorders, substance abuse, and psychiatric disorders. Indeed, glutamatergic drugs are under preclinical and clinical development for the treatment of different mental diseases that share glutamatergic neuroplasticity dysfunctions. Although clinical evidence is still limited and more studies are required, the regulation of glutamate homeostasis is attracting attention as a potential crucial target for the control of brain diseases.

Effect of Ketamine Treatment on Social Withdrawal in Autism and Autism-Like Conditions

OBJECTIVE

Ketamine and esketamine have been used in the field of psychiatry to alleviate conditions such as major depressive disorder. Our objective was to evaluate the current literature on the use of ketamine for symptoms of social withdrawal in autism spectrum disorder (ASD) and autism-like conditions.

METHODS

A comprehensive search of PubMed and Web of Science was conducted to identify literature involving the use of ketamine to treat symptoms of autism and social withdrawal. Patients with comorbid disorders were also included.

RESULTS

Two original studies were found, showing mixed results on the use of ketamine for ASD. The use of esketamine found no statistically significant results, whereas the use of intravenous ketamine was shown to alleviate symptoms of social withdrawal especially in the short term. Neither study reported a significant amount of serious adverse events. Five case reports were also included, showing decreased depressive symptoms and evidence of increased social condition.

CONCLUSIONS

Research on the use of ketamine for ASD and ASD-related conditions is limited. Evidence of improved social condition exists, but further studies should be conducted to increase sample power and test various doses and methods of administration.

Case report: Adult with bipolar disorder and autism treated with ketamine assisted psychotherapy

Background

Evidence has increased in recent years regarding the potential for ketamine to serve as a novel treatment option for a range of conditions, particularly depression (unipolar and bipolar). However, research regarding ketamine as a potential therapeutic for Autism Spectrum Disorder (ASD) is lacking, despite high overlap with bipolar depression and theoretical foundations for its use.

Case presentation

A 29-year-old man with bipolar disorder and Autism Spectrum Disorder, type 2 diabetes, presented with mood swings and suicidal thoughts, and anger outbursts occurring daily. The patient was referred by a psychiatrist due to irritability and outbursts during the previous 5 months. These outbursts were unable to be controlled by the medications prescribed, included yelling and screaming, and the patient was unable to speak with the psychiatrist. The patient underwent ketamine assisted psychotherapy with 6 initial IV infusions of ketamine over a 1 month period followed by 2 booster IV ketamine infusions. Following ketamine treatment, dramatic reductions in outbursts were observed as well as reductions in anxiety, suicidality, and depression scores.

Conclusion

This case study adds to the scant literature regarding ketamine treatment for individuals with bipolar disorder and ASD. We did not find ASD to be a contraindication for IV ketamine and ketamine assisted psychotherapy. Reductions in anger outbursts, anxiety, suicidality, and depression suggest ketamine treatment might be tailored to individuals with bipolar disorder and ASD, and additional systematized research is warranted. Although potential mechanisms of action are not clear, these data add to the discussion regarding clinical practice considerations and the potential for ketamine to improve quality of life and associated metrics.

NAP (Davunetide): The Neuroprotective ADNP Drug Candidate Penetrates Cell Nuclei Explaining Pleiotropic Mechanisms

(1) Background: Recently, we showed aberrant nuclear/cytoplasmic boundaries/activity-dependent neuroprotective protein (ADNP) distribution in ADNP-mutated cells. This malformation was corrected upon neuronal differentiation by the ADNP-derived fragment drug candidate NAP (davunetide). Here, we investigated the mechanism of NAP nuclear protection. (2) Methods: CRISPR/Cas9 DNA-editing established N1E-115 neuroblastoma cell lines that express two different green fluorescent proteins (GFPs)-labeled mutated ADNP variants (p.Tyr718* and p.Ser403*). Cells were exposed to NAP conjugated to Cy5, followed by live imaging. Cells were further characterized using quantitative morphology/immunocytochemistry/RNA and protein quantifications. (3) Results: NAP rapidly distributed in the cytoplasm and was also seen in the nucleus. Furthermore, reduced microtubule content was observed in the ADNP-mutated cell lines. In parallel, disrupting microtubules by zinc or nocodazole intoxication mimicked ADNP mutation phenotypes and resulted in aberrant nuclear-cytoplasmic boundaries, which were rapidly corrected by NAP treatment. No NAP effects were noted on ADNP levels. Ketamine, used as a control, was ineffective, but both NAP and ketamine exhibited direct interactions with ADNP, as observed via in silico docking. (4) Conclusions: Through a microtubule-linked mechanism, NAP rapidly localized to the cytoplasmic and nuclear compartments, ameliorating mutated ADNP-related deficiencies. These novel findings explain previously published gene expression results and broaden NAP (davunetide) utilization in research and clinical development.

Autism Spectrum Disorder: Neurodevelopmental Risk Factors, Biological Mechanism, and Precision Therapy

Autism spectrum disorder (ASD) is a heterogeneous, behaviorally defined neurodevelopmental disorder. Over the past two decades, the prevalence of autism spectrum disorders has progressively increased, however, no clear diagnostic markers and specifically targeted medications for autism have emerged. As a result, neurobehavioral abnormalities, neurobiological alterations in ASD, and the development of novel ASD pharmacological therapy necessitate multidisciplinary collaboration. In this review, we discuss the development of multiple animal models of ASD to contribute to the disease mechanisms of ASD, as well as new studies from multiple disciplines to assess the behavioral pathology of ASD. In addition, we summarize and highlight the mechanistic advances regarding gene transcription, RNA and non-coding RNA translation, abnormal synaptic signaling pathways, epigenetic post-translational modifications, brain-gut axis, immune inflammation and neural loop abnormalities in autism to provide a theoretical basis for the next step of precision therapy. Furthermore, we review existing autism therapy tactics and limits and present challenges and opportunities for translating multidisciplinary knowledge of ASD into clinical practice.

Ketamine-assisted psychotherapy in adolescents with multiple psychiatric diagnoses

Ketamine-assisted psychotherapy is a promising new treatment for a variety of mental disorders of adolescence. There is currently an adolescent mental health crisis, with a high prevalence of disorders, diagnostic complexity, and many adolescents failing to respond to conventional treatments. While there is strong evidence for the use of ketamine in adults for a variety of treatment-refractory mental illnesses, research in adolescents is in its early stages. Ketamine-assisted psychotherapy (KAP) has been described in adults with promising results and here we present the first published cases of the use of KAP in adolescents. The four cases include adolescents aged 14-19 at the initiation of treatment, each with a variety of comorbid diagnoses including treatment-resistant depression, bipolar disorder, eating disorders, anxiety, panic, and trauma-related symptoms. They each initially received sublingual ketamine, followed by sessions with intramuscular ketamine. Their courses varied, but each had symptomatic and functional improvements, and the treatment was well-tolerated. Subjective patient reports are included. Rapid resolution of symptomatology and suffering often occurs within months as the result of the application of KAP to adolescent psychiatric care but is not inevitable. Family involvement in the treatment process appears to be essential to success. The development of this modality may have a singularly positive impact that will expand the psychiatric toolbox and its healing potency.

An open-label study evaluating the safety, behavioral, and electrophysiological outcomes of low-dose ketamine in children with ADNP syndrome

Activity-dependent neuroprotective protein (ADNP) syndrome is a rare genetic condition associated with intellectual disability and autism spectrum disorder. Preclinical evidence suggests that low-dose ketamine may induce expression of ADNP and that neuroprotective effects of ketamine may be mediated by ADNP. The goal of the proposed research was to evaluate the safety, tolerability, and behavioral outcomes of low-dose ketamine in children with ADNP syndrome. We also sought to explore the feasibility of using electrophysiological markers of auditory steady-state response and computerized eye tracking to assess biomarker sensitivity to treatment. This study utilized a single-dose (0.5 mg/kg), open-label design, with ketamine infused intravenously over 40 min. Ten children with ADNP syndrome ages 6 to 12 years were enrolled. Ketamine was generally well tolerated, and there were no serious adverse events. The most common adverse events were elation/silliness (50%), fatigue (40%), and increased aggression (40%). Using parent-report instruments to assess treatment effects, ketamine was associated with nominally significant improvement in a wide array of domains, including social behavior, attention deficit and hyperactivity, restricted and repetitive behaviors, and sensory sensitivities, a week after administration. Results derived from clinician-rated assessments aligned with findings from the parent reports. Overall, nominal improvement was evident based on the Clinical Global Impressions - Improvement scale, in addition to clinician-based scales reflecting key domains of social communication, attention deficit and hyperactivity, restricted and repetitive behaviors, speech, thinking, and learning, activities of daily living, and sensory sensitivities. Results also highlight the potential utility of electrophysiological measurement of auditory steady-state response and eye-tracking to index change with ketamine treatment. Findings are intended to be hypothesis generating and provide preliminary support for the safety and efficacy of ketamine in ADNP syndrome in addition to identifying useful endpoints for a ketamine clinical development program. However, results must be interpreted with caution given limitations of this study, most importantly the small sample size and absence of a placebo-control group.

Vineland Adaptive Behavior Scale in a Cohort of Four ADNP Syndrome Patients Implicates Age-Dependent Developmental Delays with Increased Impact of Activities of Daily Living

Activity-dependent neuroprotective protein (ADNP) is one of the lead genes in autism spectrum disorder/intellectual disability. Heterozygous, de novo ADNP mutations cause the ADNP syndrome. Here, to evaluate natural history of the syndrome, mothers of two ADNP syndrome boys aged 6 and a half and two adults aged 27 years (man and woman) were subjected to Vineland III questionnaire assessing adaptive behavior. The boys were assessed again about 2 years after the first measurements. The skill measures, presented as standard scores (SS) included domains of communication, daily living, socialization, motor skills and a sum of adaptive behavior composite. The age equivalent (AE) and growth scale values (GSV) encompassing 11 subdomains assess the age level at which the subject's raw score is found at a norm sample median and the individual temporal progression, respectively. The norm referenced standard scores age-matched, mean 100 ± 15 of the two children showed the lowest outcome in communication (SS: 20-30). Daily living skills presented SS of 50-60, with a possible potential loss of some activities as the child ages, especially in interpersonal relationships with people outside of the immediate family (boy A). In contrast, in socialization, both children were at the SS of 38, with some positive increase to SS of ~ 45 (interpersonal relations with family members and coping skills, depending on the particular individual), 2 years later. Interestingly, there was an apparent large difference in motor skills (gross and fine) at the young age, with subject B showing a relatively higher level of skills (SS: 70), decreasing to subject A level (SS: 40) 2 years later. Together, the adaptive behavior composite suggested a level of SS: 39-48 with B showing a potential increase (SS: 41-44) and A, a substantial decrease (SS: 48-39), suggesting a strong impact of daily living skills. Adults were at SS: 20, which is the lowest possible score. AE showed minor improvements for subject A and B, with all AE values being below 3 years. GSVs for subject A showed some improvement with age, especially in interpersonal, play and leisure, and gross motor subdomains. GSV for subject B showed minor improvements in the various subdomains. Notably, all subjects showed a percentile rank < 1 compared with age-matched norms except for subject B as to motor domain (2^nd percentile) at the age of 6 years. In summary, the results, especially comparing SS and AEs between childhood and adulthood, implied a continuous deterioration of activities compared to the general population, encompassing a slower developmental process coupled to possible neurodegeneration, strongly supporting a great need for disease modifying medicinal procedures.

Signalling pathways in autism spectrum disorder: mechanisms and therapeutic implications

Autism spectrum disorder (ASD) is a prevalent and complex neurodevelopmental disorder which has strong genetic basis. Despite the rapidly rising incidence of autism, little is known about its aetiology, risk factors, and disease progression. There are currently neither validated biomarkers for diagnostic screening nor specific medication for autism. Over the last two decades, there have been remarkable advances in genetics, with hundreds of genes identified and validated as being associated with a high risk for autism. The convergence of neuroscience methods is becoming more widely recognized for its significance in elucidating the pathological mechanisms of autism. Efforts have been devoted to exploring the behavioural functions, key pathological mechanisms and potential treatments of autism. Here, as we highlight in this review, emerging evidence shows that signal transduction molecular events are involved in pathological processes such as transcription, translation, synaptic transmission, epigenetics and immunoinflammatory responses. This involvement has important implications for the discovery of precise molecular targets for autism. Moreover, we review recent insights into the mechanisms and clinical implications of signal transduction in autism from molecular, cellular, neural circuit, and neurobehavioural aspects. Finally, the challenges and future perspectives are discussed with regard to novel strategies predicated on the biological features of autism.

Novel treatments in autism spectrum disorder

PURPOSE OF REVIEW

There are currently no approved medications for the core symptoms of autism spectrum disorder (ASD), and only limited data on the management of co-occurring mental health and behavioural symptoms. The purpose of this review is to synthesize recent trials on novel treatments in ASD, with a focus on research trends in the past 2 years.

RECENT FINDINGS

No new pharmacologic agents received regulatory approval for use in ASD. Several large randomized controlled trials (RCTs) had negative or ambiguous results (e.g. fluoxetine, oxytocin). A cross-over RCT of an oral cannabinoid suggested possible benefits for disruptive behaviours. Two large-scale multicentre trials of bumetanide were terminated early for lack of efficacy. Multicenter trials using repetitive transcranial magnetic stimulation are underway. Recent meta-analyses indicate that specific behavioural and psychological interventions can support social communication and treat anxiety. Numerous novel treatment targets informed by biological mechanisms are under investigation.

SUMMARY

Recent data support the use of behavioural and psychological interventions for social communication and anxiety in ASD; data are more limited regarding pharmacotherapy for core and associated symptoms. Next steps include replication of early findings, trials of new molecular targets, and the identification of novel biomarkers, including genetic predictors, of treatment response.

Use of intranasal esketamine in a girl with treatment-resistant depression and autism spectrum disorders: a case report

Major depression is a common comorbidity in autism spectrum disorder (ASD), often difficult to identify and to treat. Autistic subjects are more at risk for suicidal thoughts and behaviors compared to typically developing peers. Unfortunately, ASD individuals are more frequently treatment-resistant and often show side-effects which reduce efficacy. Intranasal esketamine has been recently approved as an add-on medication for treatment-resistant depression (TRD), but it has never been used in ASD with comorbid major depression. Of note, a pilot study of intranasal ketamine has shown no effect on social withdrawal in ASD without depression. The present case report describes the first girl with ASD and comorbid TRD treated with intranasal esketamine.

Ketamine as a Treatment for Anorexia Nervosa: A Narrative Review

Anorexia nervosa (AN) is a highly complex disorder to treat, especially in severe and enduring cases. Whilst the precise aetiology of the disorder is uncertain, malnutrition and weight loss can contribute to reductions in grey and white matter of the brain, impairments in neuroplasticity and neurogenesis and difficulties with cognitive flexibility, memory and learning. Depression is highly comorbid in AN and may be a barrier to recovery. However, traditional antidepressants are often ineffective in alleviating depressive symptoms in underweight patients with AN. There is an urgent need for new treatment approaches for AN. This review gives a conceptual overview for the treatment of AN with ketamine. Ketamine has rapid antidepressant effects, which are hypothesised to occur via increases in glutamate, with sequelae including increased neuroplasticity, neurogenesis and synaptogenesis. This article provides an overview of the use of ketamine for common psychiatric comorbidities of AN and discusses particular safety concerns and side effects. Potential avenues for future research and specific methodological considerations are explored. Overall, there appears to be ample theoretical background, via several potential mechanisms, that warrant the exploration of ketamine as a treatment for adults with AN.

Decades of Progress in the Psychopharmacology of Autism Spectrum Disorder

Recent decades have been marked by a wave drug treatment research in autism spectrum disorder (ASD). This work has resulted in improved ability to treat commonly occurring behavioral challenges associated with ASD including most prominently irritability marked by aggression, self-injurious behavior, and severe tantrums. While treatment of interfering behavior has progressed in our field, there remain several areas of unmet medical need including most prominently a lack of any approved drug therapies for the core, defining symptoms of autism. We outline the progress to date in the field of autism drug treatment while taking a future look forward into how decades of work can inform better future steps in this field.

Novel treatments for autism spectrum disorder based on genomics and systems biology

BACKGROUND

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder with a complex underlying genetic architecture. There are currently no known pharmacologic treatments for the core ASD symptoms of social deficits and restricted/ repetitive behavior. However, there are dozens of clinical trials currently underway that are testing the impact of novel and existing agents on core and associated symptoms in ASD.

METHODS

We present a narrative synthesis of the historical and contemporary challenges to drug discovery in ASD. We then provide an overview of novel treatments currently under investigation from a genomics and systems biology perspective.

RESULTS

Data driven network and cluster analyses suggest alterations in transcriptional regulation, chromatin remodelling, synaptic transmission, neuropeptide signalling, and/or immunological mechanisms may contribute to or underlie the development of ASD. Agents and upcoming trials targeting each of the above listed systems are reviewed.

CONCLUSION

Identifying effective pharmacologic treatments for the core and associated symptom domains in ASD will require further collaboration and innovation in the areas of outcome measurement, biomarker research, and genomics, as well as systematic efforts to identify and treat subgroups of individuals with ASD who may be differentially responsive to specific treatments.

Overlapping Molecular Pathways Leading to Autism Spectrum Disorders, Fragile X Syndrome, and Targeted Treatments

Autism spectrum disorders (ASD) are subdivided into idiopathic (unknown) etiology and secondary, based on known etiology. There are hundreds of causes of ASD and most of them are genetic in origin or related to the interplay of genetic etiology and environmental toxicology. Approximately 30 to 50% of the etiologies can be identified when using a combination of available genetic testing. Many of these gene mutations are either core components of the Wnt signaling pathway or their modulators. The full mutation of the fragile X mental retardation 1 (FMR1) gene leads to fragile X syndrome (FXS), the most common cause of monogenic origin of ASD, accounting for ~ 2% of the cases. There is an overlap of molecular mechanisms in those with idiopathic ASD and those with FXS, an interaction between various signaling pathways is suggested during the development of the autistic brain. This review summarizes the cross talk between neurobiological pathways found in ASD and FXS. These signaling pathways are currently under evaluation to target specific treatments in search of the reversal of the molecular abnormalities found in both idiopathic ASD and FXS.