Which factor is NOT associated with ADHD?

High levels of academic performance are not associated with ADHD. In fact, students with ADHD often face challenges in academic settings due to difficulties with attention, impulse control, and hyperactivity. These challenges can lead to lower academic performance, rather than high levels. The other factors listed, such as parental tobacco use, exposure to heavy metals, and poor child care during infancy, have been studied and shown to be potential contributing factors to the development of ADHD, as they can influence neurodevelopment and behavior in children. Thus, identifying high academic performance as a non-associated factor makes sense within the context of understanding ADHD, where performance is usually impacted negatively.