To provide additional, required information on the pharmacokinetic profile of SHP465 in the targeted population (children and adolescents aged 6-17 years of age with ADHD).

Inclusion Criteria:

1. Age 6 to 17 years inclusive at the time of consent/assent. The date of signature of the informed consent/assent is defined as the beginning of the Screening Period. This inclusion criterion will only be assessed at the first screening visit.
2. Male, or non-pregnant, non-lactating female who agrees to comply with any applicable contraceptive requirements of the protocol or females of non-childbearing potential.
3. Subject meets Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria for a primary diagnosis of ADHD based on an accepted ADHD diagnostic instrument and documented in the subject's medical record. Subject's ADHD is currently adequately controlled with an amphetamine-based product.
4. Subject is functioning at an age appropriate level intellectually, as determined by the investigator.
5. Must be considered "healthy". Healthy status is defined by absence of evidence of any active or chronic disease other than their ADHD following a detailed medical and surgical history, a complete physical examination including vital signs, 12-lead ECG, hematology, blood chemistry, and urinalysis.
6. Ability to swallow a capsule of investigational product whole.

Exclusion Criteria:

1. Current use of any ADHD medication other than an amphetamine-based product.

2. History of any hematological, hepatic, respiratory, cardiovascular, renal, neurological or psychiatric disease, gall bladder removal, or current or recurrent disease other than their ADHD

3. Current or relevant history of physical or psychiatric illness, any medical disorder that may require treatment

4. Subject has a current, controlled or uncontrolled, comorbid psychiatric diagnosis with significant symptoms

5. Subject meets DSM-V diagnosis of conduct disorder.

6. Subject is considered a suicide risk in the opinion of the investigator, has previously made a suicide attempt, or is currently demonstrating active suicidal ideation.

7. Subject is underweight based on Centers for Disease Control and Prevention (CDC) body mass index (BMI)- for-age sex-specific values

8. Subject is significantly overweight based on CDC BMI-for-age sex specific values

9. Subject has a known history of symptomatic cardiovascular disease, advanced arteriosclerosis, structural cardiac abnormality, cardiomyopathy, serious heart rhythm abnormalities, coronary artery disease, or other serious cardiac problems

10. Subject has a concurrent chronic or acute illness, disability, or other condition that might confound the results of safety assessments conducted in the study

11. Subject has a history of seizure, a chronic or current tic disorder, or a current diagnosis of Tourette's Disorder. Subject has a history of tics that are judged to be exclusionary.

12. Subject's blood pressure measurements exceed the 90th percentile for age, sex, and height

13. Subject has a known history of hypertension.

14. Subject has a known family history of sudden cardiac death or ventricular arrhythmia.

15. Subject has any clinically significant ECG or clinically significant laboratory abnormality

16. Subject has abnormal thyroid function

17. Known or suspected intolerance or hypersensitivity to the investigational product(s), closely-related compounds, or any ingredients.

18. History of alcohol or other substance abuse within the last year. Subjects with a lifetime history of amphetamine, cocaine, or other stimulant abuse and/or dependence will be excluded.

19. Use Within 30 days prior to the first dose of investigational product:

    • have used an investigational product
    • have been enrolled in a clinical study (including vaccine)
    • have had any substantial changes in eating habits

20. A positive screen for alcohol or drugs of abuse. A positive hepatitis B surface antigen (HBsAg); hepatitis C virus (HCV); or HIV antibody screen.

21. Use of tobacco in any form in the last 30 days

22. Prior screen failure, enrollment, or participation in this study.