The TEAM Study - Treatment Efficacy for Autism/Attention Using Mixed Amphetamine

The investigators are conducting a 10-week brain imaging and medication study. They are doing the research to study the response of Attention-Deficit/ Hyperactivity Disorder (ADHD) in youth with Autism Spectrum Disorder (ASD) on extended-release formulation of mixed amphetamine salts (MAS) (also know as Adderall XR). The investigators also want to find out if taking MAS has any effect on the brains of children and adolescents with ADHD and ASD. This study will help researchers better understand how the use of MAS to treat ADHD effects children and adolescents with ASD. The investigators will compare MAS to a placebo. The placebo will look exactly like the MAS capsules but will contain no MAS. During this study, participants may get a placebo instead of MAS. Placebos are used in research studies to see if the study results are due to the study drug or due to other reasons. Participants with ASD and ADHD will complete 4-weeks of treatment with the study medication or placebo. They will complete bi-weekly study visits virtually via a telemedicine platform with the study doctor and complete questionnaires. On alternating weeks, they will meet with a Massachusetts General Hospital (MGH) study team member to discuss medication adherence and potential side effects. Participants will have the option to attend all study visits in-person if participants prefer. They will also complete baseline and endpoint Magnetic Resonance (MR) scan visits at Massachusetts Institute of Technology (MIT). During the MR Scan visits, they will complete a series of tasks to measure inattention, impulsivity, reward sensitivity, decision-making, and working memory. Participants without ADHD or ASD will complete eligibility screening with MGH. If eligible, they will be invited to baseline and endpoint MR scan visits at MIT. During the MR Scan visits, they will complete a series of tasks to measure inattention, impulsivity, reward sensitivity, decision-making, and working memory.