title: Neural activation during response inhibition in adult attention-deficit/hyperactivity disorder: preliminary findings on the effects of medication and symptom severity.
abstract: Studies of adults with attention-deficit/hyperactivity disorder (ADHD) have suggested that they have deficient response inhibition, but findings concerning the neural correlates of inhibition in this patient population are inconsistent. We used the Stop-Signal task and functional magnetic resonance imaging (fMRI) to compare neural activation associated with response inhibition between adults with ADHD (N=35) and healthy comparison subjects (N=62), and in follow-up tests to examine the effect of current medication use and symptom severity. There were no differences in Stop-Signal task performance or neural activation between ADHD and control participants. Among the ADHD participants, however, significant differences were associated with current medication, with individuals taking psychostimulants (N=25) showing less stopping-related activation than those not currently receiving psychostimulant medication (N=10). Follow-up analyses suggested that this difference in activation was independent of symptom severity. These results provide evidence that deficits in inhibition-related neural activation persist in a subset of adult ADHD individuals, namely those individuals currently taking psychostimulants. These findings help to explain some of the disparities in the literature, and advance our understanding of why deficits in response inhibition are more variable in adult, as compared with child and adolescent, ADHD patients.
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA. Electronic address: econgdon@ucla.edu.
authors.forename: Eliza
authors.initials: E
authors.lastname: Congdon
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Lori L
authors.initials: LL
authors.lastname: Altshuler
authors.affiliation: Department of Psychology, University of Texas at Austin, Austin, TX, USA.
authors.forename: Jeanette A
authors.initials: JA
authors.lastname: Mumford
authors.affiliation: Department of Psychiatry, Zucker Hillside Hospital, Glen Oaks, NY, and Feinstein Institute for Medical Research, Manhasset, NY, USA.
authors.forename: Katherine H
authors.initials: KH
authors.lastname: Karlsgodt
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Fred W
authors.initials: FW
authors.lastname: Sabb
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Ventura
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: McGough
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA; Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Edythe D
authors.initials: ED
authors.lastname: London
authors.affiliation: Department of Psychology, Yale University, New Haven, CT, USA.
authors.forename: Tyrone D
authors.initials: TD
authors.lastname: Cannon
authors.affiliation: Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA; Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Bilder
authors.affiliation: Department of Psychology, University of Texas at Austin, Austin, TX, USA; Department of Neurobiology and Imaging Research Center, University of Texas at Austin, Austin, TX, USA.
authors.forename: Russell A
authors.initials: RA
authors.lastname: Poldrack
mesh_terms: D000328:Adult; D001288:Attention / Q000187:drug effects / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D001931:Brain Mapping; D000697:Central Nervous System Stimulants / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013647:Task Performance and Analysis; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants
keywords: Adults; Functional magnetic resonance imaging (fMRI); Hyperactivity; Inhibitory control; Psychostimulants; Stop-Signal task