ADHD-P1 is characterized primarily by:

• inattention
• easy distractibility
• disorganization
• procrastination
• forgetfulness

Different countries have used different ways of diagnosing ADHD-PI. In the United Kingdom, diagnosis is based on quite a narrow set of symptoms, and about 0.5–1% of children are thought to have attention or hyperactivity problems. The United States used a much broader definition of the term ADHD. As a result, up to 10% of children in the U.S. were described as having ADHD.

Current estimates suggest that ADHD is present throughout the world in about 1–5% of the population. About five times more boys than girls are diagnosed with ADHD.

Medications include two classes of drugs, stimulants and non-stimulants.

Drugs for ADHD are divided into 2 classes: first-line and second-line medications. First-line medications include several of the stimulants, and tend to have a higher response rate and effect size than second-line medications. Although medication can help improve concentration, it does not cure ADHD and the symptoms will come back once the medication stops.