AD/HD symptoms usually arise in early childhood. Current diagnostic criteria indicate that the disorder is marked by behaviors that are long lasting and evident for at least six months, with onset before age seven. There are three primary subtypes, each associated with different symptoms.

AD/HD - Primarily Inattentive Type:
• Fails to give close attention to details or makes careless mistakes.
• Has difficulty sustaining attention.
• Does not appear to listen.
• Struggles to follow through on instructions.
• Has difficulty with organization.
• Avoids or dislikes tasks requiring sustained mental effort.
• Is easily distracted.
• Is forgetful in daily activities.

AD/HD - Primarily Hyperactive/Impulsive Type:
• Fidgets with hands or feet or squirms in chair.
• Has difficulty remaining seated.
• Runs around or climbs excessively.
• Has difficulty engaging in activities quietly.
• Acts as if driven by a motor.
• Talks excessively.
• Blurts out answers before questions have been completed.
• Has difficulty waiting or taking turns.
• Interrupts or intrudes upon others.

AD/HD - Combined Type:
• Meets both inattentive and hyperactive/impulsive criteria.

Because everyone shows signs of these behaviors at one time or another, the guidelines for determining whether a person has AD/HD are very specific. In children, the symptoms must be more frequent or severe than in other children of the same age. In adults, the symptoms must be present since childhood and affect one’s ability to function in daily life. These behaviors must create significant difficulty in at least two areas of life, such as home, social settings, school, or work.