This double-blind, randomized, controlled trial (RCT) has the aim to evaluating the effectiveness of increasing Total Antioxidant Capacity (TAC) as add-on intervention in two cohorts of patients with Autism Spectrum Disorder (ASD) who have received Risperidone (0.02-0.06 mg/KgBW) and Behavior Therapy as maintenance therapy. Both groups will receive placebo pill or Vitamin E and C pill using randomization. Clinical Symptoms, Aberrant Behavior and Quality of Life in Children with ASD will be assessed after 12 weeks of treatment in this study. Primary outcome measures of efficacy is Aberrant Behavior Checklist- Irritability (ABC-Irritability) and Secondary outcome measures include Childhood Autism Rating Scale (CARS), Clinical Global Impression Scale - Improvement (CGI-I), The PedsQL and The WHOQOL BREF.

The continuation of ASD throughout life makes all efforts to optimize the abilities of children with ASD as early as possible so that their quality of life becomes better important. Management to improve current symptoms and overcome aberrant behavior in children with ASD generally focuses on behavioral intervention, psychotherapy and even pharmacotherapy, but the results are not satisfactory because it takes time, is expensive and unexpected side effects often occur after administering pharmacotherapy. On the other hand, research related to the role of oxidative stress has suggested a potential relationship between oxidative stress and autism pathophysiology that is not correlated with age and the underlying pathogenesis, but damage caused by oxidative stress will exacerbate dysfunction in children with ASD through chronic inflammatory responses, DNA and protein damage and mitochondrial superoxide production. Oxidative stress will influence the clinical symptoms and pathogenesis of ASD. Therefore, efforts to control the balance of oxidative stress to improve symptoms and neuropsychological deficits in patients with ASD are important. Lack of antioxidant capacity in children with ASD to neutralize and remove oxidants has been associated with the severity of clinical symptoms and aberrant behavior in children with ASD. Therefore, efforts to increase antioxidant capacity through providing antioxidants can offer a new strategy for dealing with accompanying symptoms in children with ASD.

Vitamin E and Vitamin C are non-enzymatic antioxidants which function to strengthen the work of enzymatic antioxidants in the oxidant-elimination, oxidation-reduction cycle process that occurs in the brain. Its includes in group of antioxidants which also referred as chain breaking. When used together with vitamin C which can function as a water-soluble antioxidant and other enzyme cofactors, reduced vitamin C can directly regenerate vitamin E which simultaneously undergoes oxidation to become ascorbate. Therefore, the use of vitamin C will be more effective when used together with vitamin E. Research has shown that administration with antioxidants such as vitamin E and vitamin C has a good effect on clinical symptoms and behavior in children with ASD.

In this randomized controlled trial (RCT), patients with Autism Spectrum Disorder (ASD) who have received Risperidone and Behavior Therapy as maintenance therapy will be randomly assigned to receive either a placebo or a combination of Vitamins E (150-200 IU per day) and C (100-200 mg per day) for a duration of 3 months. This study was designed to verify whether increasing the TAC using Vitamin E and C improves clinical symptoms, aberrant behaviors, and quality of life in children with ASD.

This study shall include 50 patients with ASD, aged 3-9 years old. The study design of this RCT was balanced to all of patients treated with maintenance therapy as usual, so that half of the patients will receive placebo, and the remaining half will receive Vitamin E and C during 3 months. The purpose is to observe whether the increase of TAC could improve the clinical symptoms, aberrant behavior and quality of life in ASD patients. In addition to clinical and psychometric parameters, TAC will be measured at baseline, after 6 weeks and 12 weeks, by collecting 30-60 ml of fresh urine, a general urinalysis examination to rule out acute urinary tract infections, The TAC examination is carried out when the urine pH is normal and measurement with a calorimetric kit with enzyme method, ABTS.

Inclusion Criteria:

1. Both parents or a legally authorized patient representative (LAR) must provide written informed consent. The parents and guardian must be able to understand and comply with the experimental protocol with a minimum of junior high school education.
2. Parents earn no less than IDR 3,434,298 (South Sulawesi Province Minimum Wage for 2024).
3. Subjects of both sexes, aged between 3-9 years old, may be included in the study.
4. The subject must meet DSM-5 criteria for a primary diagnosis of Autism.
5. Patients treated with Risperidone (0.02-0.06 mg/KgBW) are enrolled only if the treatment and dosage of these drugs has been constant for at least 2 months prior to enrollment in the trial and is kept constant throughout the 3-month duration of the trial.
6. Patients undergoing any kind of behavioral intervention must have must have underwent the intervention at least 2 sessions prior to enrollment and the intervention must remain unchanged throughout the 3-month duration of the trial.
7. Baseline Clinical Global Impression - Severity (CGI-S) score below 7.
8. The patient is able to swallow the capsule or his/her parents are available to open it and administer immediately its content in a small quantity of juice or soft-drink.

Exclusion Criteria:

1. Patients with organic disease and/or congenital malformation including known genetic syndromes for example, Rett syndrome, fragile-X syndrome, and Down Syndrome etc.).
2. Patients with autism secondary to epileptic encephalopathy or with idiopathic autism co-morbid with seizures more frequent than one episode every 6 months despite ongoing anti epileptic drug therapy.
3. Patients treated with anticoagulants.
4. Patients with serious medical illnesses (chronic renal disease, severe liver disease, cardiovascular disorders, malignant tumors, HIV infection).
5. Patients with a history of acute cerebrovascular episodes.
6. Patients with a history of stomach bleeding or active peptic ulcer.
7. Patients with documented allergy, hypersensitivity or intolerance to one of the excipients of the experimental or comparative product.
8. Patients have been consuming other antioxidants.
9. Patients with active urinary tract infections.
10. Patients with poor compliance and or no control back to the Hospital.

Trial interruption criteria:

1. Patients whose medical conditions require starting treatment with anticoagulants.
2. Patients with severe medical conditions starting during the 3-month duration of the trial.
3. Patients who undergo a change in psychopharmacological or behavioral treatment during the 3-month duration of the trial.

Participants, all care providers, investigators and outcome assessors are blind to treatment status, as well as patients and family. Three investigators, who have no direct contact with patients and families, are responsible for managing the study procedures or treatments. Another investigator, who is not involved in assessing the outcomes, interacts with families to answer any questions regarding the trial or medical issues. This investigator also ensures that the outcome assessors are not influenced by any contact with families between the assessment periods (0, 6, and 12 weeks). Families are asked to refrain from discussing their experiences and the trial outcomes on social media.