That sounds so much like my nephew. He’s the smartest kid, but his grades were slipping because he’d just forget to turn in completed work. The frustration and the “losing track of time” is so real—it’s not laziness, it’s like the brain’s internal manager is on a coffee break. It’s smart to want to understand it first. We found that getting a full picture was key. It’s usually not one single test, but a process with interviews and rating scales. There’s a really clear, no-judgement article on the PNS site that breaks down the different private adhd assessment and diagnosis . It helped my sister feel prepared and know what to ask for. Wishing you and your teen all the best. Starting with understanding is the most powerful step.