Attention-deficit disorder in adults with or without hyperactivity: where is the difference? A study in humans using short echo H-1-magnetic resonance spectroscopy

The DSM-IV distinguishes three subtypes of attention deficit hyperactivity disorder: The predominantly inattentive subtype (ADD), the hyperactive-impu lsive subtype (ADHD) and the combined subtype. We used short echo time H-1- magnetic resonance spectroscopy (TE = 30 ms, TR = 3000 ms) for absolute qua ntification of neurometabolites using the LC model algorithm to investigate a possible metabolic neuropathology in adult patients with ADD and ADHD an d compared their spectra with healthy controls (n = 5 in each group). Spect ra were acquired in the left dorsolateral prefrontal cortex and the left st riatum. There was a significant group difference in N-acetylaspartate (NAA) concentration in the left dorsolateral prefrontal cortex distinguishing pa tients with the ADHD from patients with pure ADD and healthy controls. The absolute NAA concentration was significantly reduced only in the ADHD group . Since NAA-depletion reflects a state of neuronal dysfunction, this findin g indicates evidence of subtle left prefrontal neuropathology in ADHD in ad ults. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.