Experimental fMRI Study of Guanfacine and Lisdexamfetamine in ADHD Adolescents

Summary

This is not a clinical trial. The aim of this study is to understand the mechanism of action of two recently licensed drugs for ADHD on brain function. We will compare the brain activation changes elicited by Guanfacine extended release (GXR; a non-stimulant drug) with the brain activation changes elicited by Lisdexamfetamine (LISDEX; a stimulant drug) and by placebo in 20 drug-free patients with ADHD using functional Magnetic Resonance Imaging (fMRI). For this purpose we intend to scan participants during their performance of tasks of attention, working memory, and inhibition, which we know from previous studies to elicit abnormal brain activation patterns in ADHD patients (Rubia et al., 2005; Smith et al., 2006).

Timeline

Start

2018-10-01

Primary completion

2022-12-31

Completion

2025-03-31

Publications

• Background Rubia K, Smith AB, Brammer MJ, Toone B, Taylor E. Abnormal brain activation during inhibition and error detection in medication-naive adolescents with ADHD. Am J Psychiatry. 2005 Jun;162(6):1067-75. doi: 10.1176/appi.ajp.162.6.1067.
• Background Smith AB, Taylor E, Brammer M, Toone B, Rubia K. Task-specific hypoactivation in prefrontal and temporoparietal brain regions during motor inhibition and task switching in medication-naive children and adolescents with attention deficit hyperactivity disorder. Am J Psychiatry. 2006 Jun;163(6):1044-51. doi: 10.1176/ajp.2006.163.6.1044.
• El Masri S, Kowalczyk OS, Chiu TH, Criaud M, Lukito S, Mazibuko N, Salazar de Pablo G, Perez Rodriguez V, Makos O, Lam SL, Westwood S, Eaton-Turner A, Bozhilova N, Conti A, Santosh P, Roessner V, Kohls G, Mehta MA, Rubia K. Differential effects of a single dose of Lisdexamfetamine and Guanfacine on cognitive function in children with ADHD. Front Psychiatry. 2025 Nov 3;16:1676472. doi: 10.3389/fpsyt.2025.1676472. eCollection 2025.

Drugs

Indications