An fMRI Study of Stimulant vs. Non-Stimulant Treatment of ADHD

Children with Attention-Deficit/Hyperactivity Disorder (ADHD) are typically treated with two types of medications with differing mechanisms of action: stimulants and non-stimulants. The stimulant Vyvanse (lisdexamfetamine, LDX), and the non-stimulant Intuniv (extended-release guanfacine, GXR), are both FDA approved treatment for ADHD. Clinical trials have shown that both medications are effective in reducing ADHD symptoms, although the neurobiological mechanisms by which Vyvanse and Intuniv produce these effects remain unknown. The aim of this study is to examine the mechanisms by which LDX and GXR reduce symptoms in patients with ADHD. MRI scanning will be used to identify treatment-related changes in brain structure and function.

Children with ADHD and age and sex-matched healthy controls will be scanned at the beginning of the study. In this first part of the study, MRI findings will be compared between the two groups to see whether brain functioning of children with ADHD differs from that of healthy children. In the second part of the study, the children with ADHD will meet weekly with the study doctor and be administered either extended-release guanfacine (Intuniv) or lisdexamfetamine (Vyvanse) for 6 weeks. Selection into either treatment group will be randomly determined. At the end of the study, the children with ADHD treated with either medication will have a second MRI scan. The findings of that second MRI scan will be compared to the first MRI scan in order to examine brain changes due to the medication. These second MRI scans will also be compared to the scans of the healthy controls.

Eligibility Criteria:
Inclusion Criteria:

ADHD Participants:

* The participant satisfies Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for a primary diagnosis of ADHD, any subtype.

Healthy Control Participants:

* The participant must have no current DSM Axis I psychiatric disorder.

All Participants:

* Participants must provide assent and a legal guardian must provide consent.
* The participant is male or female and between 6 - 17 years of age and in good physical health.
* Girls of childbearing potential must have a negative urine pregnancy test and, if sexually active, must be using adequate contraception.
* The participant is English speaking.

Exclusion Criteria:

ADHD Participants:

* The participant has a current comorbid DSM Axis I psychiatric diagnosis or other symptomatic manifestations that, in the opinion of the study doctor, will contraindicate lisdexamfetamine or guanfacine treatment or confound safety assessments.
* The participant meets DSM-5 criteria for current substance abuse and/or dependence.
* The participant is currently taking or has taken within the past 4 months, a psychotropic medication.
* The participant has a documented allergy or intolerance to lisdexamfetamine or guanfacine products.
* The participant has a diagnosis or a history of cardiovascular disease or any other serious medical illness.
* The participant is pregnant or lactating.
* The participant is actively suicidal.
* MRI contraindications (e.g., irremovable metal on the body, pacemaker, braces)
* The participant has a full-scale intelligence quotient (IQ) less than 70.
* The participant has a history of seizure (except febrile seizure).

Healthy Controls:

* The participant meets DSM criteria for current substance abuse and/or dependence.
* The participant is currently taking a psychotropic medication.
* The participant has a history of a serious medical illness.
* The participant is pregnant or lactating.
* MRI contraindications (e.g., irremovable metal on the body, pacemaker, braces)
* The participant has a full-scale intelligence quotient (IQ) less than 70.
* The participant has a history of seizure (except febrile seizure).