• Participant and/or legal caregiver must be willing and able to give informed consent/assent for participation in this study.

• Participant and/or legal caregiver must be willing and able (in the Investigator's opinion) to comply with all study requirements.

• Participant must be between 4 and 17 years of age (inclusive) at time of enrollment.

• Participant must have a confirmed diagnosis of ASD based on supportive evidence (e.g. referring physician's report, medical records, such as ADOS or CARS, etc.).

• Participant must have the ability to consistently take medication (via pill, liquid or mixed with food/liquid).

• Participant must have a confirmed diagnosis of ADHD (based upon DSM-5 criteria and supportive evidence).

• Participant must have a consistent reporter (e.g., parent) who spends regular time with the child.

• Participant can be on other psychotropic medications (selective serotonin reuptake inhibitor (SSRI), atypical antipsychotic, anticonvulsant) if dose has been stable for \> 4 weeks prior to consent with no plans for a dose change during the study.

• It has been at least 7 days since the participant last took an ADHD medication and the presiding clinician believes this to be a sufficient amount of time.

⁃ Caregiver must be sufficiently fluent in English or Spanish to be able to complete questionnaires relevant to this study.