According to the DSM-V,¹ ADHD (Attention-Deficit Hyperactivity Disorder) has three possible presentation types:
- Predominantly Hyperactive-Impulsive Presentation
- Predominantly Inattentive Presentation
- Combined Presentation
The combined presentation is just like it sounds, meaning someone shows symptoms of both hyperactive-impulsive behavior and inattentive behavior. This is the most common presentation of ADHD.
These presentations can change over time, so someone could have hyperactive-impulsive symptoms as a child, but inattentive symptoms as an adult.
The name ADD is actually an outdated term that should no longer be used. In general, it referred to an inattentive type but is no longer an official term and shouldn't be used.
In fact, if you are seeing a doctor about a diagnosis and they mention "ADD", it's kind of a tell that they aren't up to date on the latest information on ADHD. They may not be the best source for help or diagnosis.
¹ Diagnostic and Statistical Manual of Mental Disorders, 5th Edition