Three forms of ADHD were historically defined by the Diagnostic and Statistical Manual of Psychiatric Disorders (DSM)2:
- Primarily hyperactive-impulsive type
- Primarily inattentive type (formerly called ADD)
- Primarily combined type
Primarily Hyperactive-Impulsive ADHD
People with predominantly hyperactive-impulsive ADHD behave with no self regulation “as though powered by a motor,” moving, squirming, and communicating at even the most inconvenient moments. They are impulsive, they are impatient and they disturb people.
Primarily Inattentive ADHD
People with the inattentive subtype of ADHD have trouble concentrating, completing activities, and following orders. Easily confused and forgetful, they are. They might be daydreamers who constantly lose track of homework, mobile phones, and conversations.
Experts agree that, since they may not appear to disturb the learning environment, often children with the inattentive subtype of ADHD may go undiagnosed.
Primarily Combined Type ADHD
A variation of all the signs described above is displayed by people with combined-type ADHD. Patients of this combination form of ADHD will be diagnosed by a psychiatrist if they follow the criteria for primarily inattentive ADHD and primarily hyperactive-impulsive ADHD. That is, 6 of the 9 signs described by each sub-type must be seen.