This study focuses on evaluating the medicine NRCT-101SR for teenagers aged 13-17 with ADHD, a condition that makes it hard to focus and can cause hyperactive and impulsive behavior. The study compares this medicine to a placebo, a harmless pill that looks like the real medicine, over six weeks. Participants will be randomly assigned to take either the medication or the placebo without knowing which one they are receiving (this is called "double-blind"). There are about 160 places in this study.

• The study lasts 6 weeks, with an optional extra 6 weeks.
• Participants will take a math test and an ADHD symptom test.
• Blood samples may be taken from some participants to study how the body processes the medicine.

Before joining, teens must have a diagnosis of ADHD and meet other health criteria. They cannot join if they have certain health issues like a history of severe mental disorders or recent substance abuse. Female participants must agree to use birth control if they are of childbearing age. Participants cannot have severe heart or liver problems, and they must not be in another study at the same time.