Reduced GABA concentration in attention-deficit/hyperactivity disorder

Context: Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder characterized by a deficit in behavioral inhibition. Recent evidence also suggests a deficit in cortical inhibition via the GABA (γ- aminobutyric acid)-ergic system. Objective: To investigate the GABAergic component of ADHD using magnetic resonance spectroscopy. Design: Cross-sectional study. Setting: Participants were recruited through local schools, local pediatric and other community clinics, and through advertisement in regional publications. Magnetic resonance spectroscopy was performed within the research institute. Participants: Children (age range, 8-12 years) in a typically developing control group vs a group with ADHD were compared. Main Outcome Measures: J-difference-edited magnetic resonance spectroscopy at 3 T was used to measure GABA concentration in a volume that included primary somatosensory and motor cortices. Results: GABA concentration is reduced in children with ADHD compared with typically developing control subjects. Conclusion: Our finding of reduced GABA concentration in ADHD is concordant with recently reported deficits in short intracortical inhibition in ADHD and suggests a GABAergic deficit in ADHD.