Attention Deficit Disorder symptoms are grouped into different categories: Inattention, Hyperactive, Impulsive, and Combined. They describe the dominant behavioral characteristics of the condition.
Based on the above symptom classifications, there are 3 types of ADHD that are also behaviorally descriptive: Predominantly Inattentive, Predominantly Hyperactive-Impulsive, and a combination of the two called Combined Type.
In addition, brain researchers such as Dr. Daniel Amen believe that there are more than 3 types of ADHD, which he highlights in his recommended book: Healing ADD: The Breakthrough Program That Allows You to See and Heal the 6 Types of ADD.
Signs of ADHD Inattentive type include:
Difficulty focusing and paying attention to details and tendency to make careless mistakes in class work or other tasks/activities;
Producing school work that is often careless and messy;
Inability to sustain focus and attention on tasks or activities;
Difficulty concentrating and completing tasks that require focus and require concentration;
Frequent shifting from one task or activity to another without completion.
Prone to frequent daydreaming; appearing to be "spacey";
Disorganization, including workspace and work habits;
Frequent forgetfulness; losing keys, forgetting to bring lunch for school, etc.;
Failure to complete tasks such as homework or chores;
Frequent inability follow instructions; failure to listen to directions.
Frequent squirming; fidgeting;
Inability to remain seated; getting up frequently to walk or run around; disrupting class;
Running or climbing excessively when it's inappropriate (in teens and adults this may manifest as restlessness);
Displaying challenges when playing quietly; inability to engage in quiet leisure activities;
Being constantly on the go, i.e. the "Energizer Bunny";
Frequent excessive talking;
Keep in mind that hyperactive symptoms often differ depending on age and developmental stage. Hyperactive ADHD symptoms in adults, for example, are often characterized by feelings of restlessness, excessive chattiness, frequently interrupting others, difficulty engaging in relaxing activities, etc.
Blurting out answers to questions;
Difficulty awaiting one's turn;
Frequently interrupting others which creates social awkwardness and causes problems in work, school, and relationship/peer settings.
For a diagnosis of ADHD to be given, symptoms must have been present prior to age 7, must occur in multiple environments (home, school, work, etc), must significantly impair functioning in these environments, must have occurred for at least 6 months, and must not be the result of any other medical condition.