ADHD is a developmental disorder, in that, in the diagnosed population, certain traits such as impulse control significantly lag in development when compared to the general population. This developmental lag has been estimated to range between 30-40 percent in ADHD patients in comparison to their peers; consequently these delayed attributes are considered an impairment. ADHD has also been classified as a behavior disorder and a neurological disorder or combinations of these classifications such as neurobehavioural or neurodevelopmental disorders.

During the elementary years an ADHD student will have more difficulties with work completion, productivity, planning, remembering things needed for school, and meeting deadlines. Oppositional and socially aggressive behaviour is seen in 40-70 percent of children at this age. Even ADHD teens with average to above average intelligence show "chronic and severe under achievement". Fully 46% of those with ADHD have been suspended and 11% expelled.  Thirty seven percent of those with ADHD do not get a high school diploma even though many of them will receive special education services. The combined outcomes of the expulsion and dropout rates indicate that almost half of all ADHD students never finish high school. Only five percent of those with ADHD will get a college degree compared to twenty seven percent of the general population. (US Census, 2003)

A study by the U.S. Department of Energy’s Brookhaven National Laboratory in collaboration with Mount Sinai School of Medicine in New York suggest that it is not the dopamine transporter levels that indicate ADHD, but the brain's ability to produce dopamine itself. The study was done by injecting 20 ADHD subjects and 25 control subjects with a radiotracer that attaches itself to dopamine transporters. The study found that it was not the transporter levels that indicated ADHD, but the dopamine itself. ADHD subjects showed lower levels of dopamine across the board. They speculated that since ADHD subjects had lower levels of dopamine to begin with, the number of transporters in the brain was not the telling factor.

There are several clinically proven effective options available to treat teens diagnosed with ADHD. It has been believed that ADHD is treated most effectively, and cost efficiently, with medication. However, recent long term studies now cast serious doubt to this assertion. "Drugs such as Ritalin and Concerta and Adderall work no better than therapy after three years of treatment. The findings by an influential US study also suggested long-term use of the drugs could stunt children's growth. It said that the benefits of drugs had previously been exaggerated." Psychotherapy is another option, with or without medication.  Omega-3 fatty acids, zinc and magnesium may have benefits with regards to ADHD symptoms.
 
Comorbid disorders or substance abuse can make finding the proper diagnosis and the right overall treatment more costly and time-consuming.  Social impairment for those with ADHD is seen at both school and play. They often have more troubled relationships with peers or family members. Those with ADHD are at greater risk of: injury, abnormal risk taking, smoking, having learning disabilities, other mental disorders, teen pregnancy, substance abuse, involvement with the criminal justice system, and having a poorer driving record.