What is a thesis?

In the Introduction below what would be the thesis?

How do you determine the thesis?

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder among U.S. children, with 6.4 million children between the ages of 4-17 having been diagnosed (Visser et al. 2014). A diagnosis of ADHD in a child can have stigmatizing beliefs that can lead to less inclusive attitudes in those who do not have prior knowledge about the disorder (Toye, 2019). A school environment for a child with ADHD can open a gateway for these negative stigmas against the condition. No child wants to feel left out or treated differently than the peers around them because of a condition that is out of their control. School can be a struggle for any child but for a child with ADHD it can be a nightmare of difficulties that can include emotional and behavior problems, poor education, and burdensome friendships.