Minimum 24 subjects aged 8-12 with a diagnosis of ADHD will be prescribed extended release guanfacine (Intuniv) to assess impact, if any, on working memory. Pre and post testing using a standardized battery of tests for effect on symptoms of ADHD and working memory will be administered and assessed.

Inclusion Criteria:

1.Meet DSM-IV criteria for ADHD, combined, inattentive, or hyperactive/impulsive subtype, as evidenced by minimum score of 24 on the ADHD-RS-IV at baseline

• 2 Outpatient status
• 3. Age 8-12 (inclusive) at baseline
• 4. Males or Pre-menarchal females
• 5. English-speaking parent and subject
• 6. If on stimulant medication, has demonstrated sub-optimal response to treatment ad is willing to be washed out (discontinued) from stimulant
• 7. Intellectual capacity to provide assent, as deemed by the Principal Investigator
• 8. No known cardiac history, including bradycardia, heart block, syncope or tachycardia
• 9. No known history of hypotension or hypotension at baseline
• 10. Willing to provide informed consent/ assent per IRB protocol

Exclusion Criteria:

• • 1.Meet DSM-IV criteria for ADHD, combined, inattentive, or hyperactive/impulsive subtype, as evidenced by minimum score of 24 on the ADHD-RS-IV at baseline

  • 2 Outpatient status
  • 3. Age 8-12 (inclusive) at baseline
  • 4. Males or Pre-menarchal females
  • 5. English-speaking parent and subject
  • 6. If on stimulant medication, has demonstrated sub-optimal response to treatment ad is willing to be washed out (discontinued) from stimulant
  • 7. Intellectual capacity to provide assent, as deemed by the Principal Investigator
  • 8. No known cardiac history, including bradycardia, heart block, syncope or or tachycardia
  • 9. No known history of hypotension or hypotension at baseline
  • 10. Willing to provide informed consent/ assent per IRB protocol 11. No history of hepatic or renal impairment