Frontostriatal neuroimaging findings differ in patients with bipolar disorder who have or do not have ADHD comorbidity.
BACKGROUND
The inferior frontal cortical (IFC)-striatal network plays an integral role in response inhibition and is compromised in patients with Bipolar Disorder (BP) or Attention-Deficit/Hyperactivity Disorder (ADHD). Prior BP functional neuroimaging studies have not accounted for ADHD comorbidity despite its high prevalence.


METHODS
The authors conducted an fMRI study using a response inhibition task (Go-NoGo) in 32 euthymic adults with BP, half with comorbid ADHD (BP/ADHD); 16 adults with ADHD alone; and 30 healthy controls. Within- and between-group whole-brain analyses were performed to assess for significant neural function differences.


RESULTS
All groups activated frontal and striatal regions involved in response inhibition. ANOVA results demonstrated significant interaction effects of BP and ADHD in the anterior and posterior cingulate, left superior and middle frontal gyri and left inferior parietal lobule. Follow-up comparisons showed significant differences between BP subjects with and without ADHD. Other regions demonstrated main effects of BP (left inferior frontal gyrus, left middle frontal gyrus, right superior frontal gyrus and left insula) and ADHD (left inferior frontal gyrus, left precentral gyrus and right anterior cingulate).


CONCLUSIONS
This study, as the first of its kind, requires replication using large sample sizes and controlling for potential effects of medication.


CONCLUSIONS
Euthymic bipolar adults with comorbid ADHD have significantly different neural activation patterns from BP patients without this comorbidity. If understanding of the neurobiology of bipolar disorder is to be achieved, it is critical to control for this potential confound, something not done by most prior fMRI studies of adults with BP.
Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, 760 Westwood Plaza, Los Angeles, CA 90024, USA.
Jennifer D
JD
Townsend
Catherine A
CA
Sugar
Patricia D
PD
Walshaw
Roxanne E
RE
Vasquez
Lara C
LC
Foland-Ross
Teena D
TD
Moody
Susan Y
SY
Bookheimer
James J
JJ
McGough
Lori L
LL
Altshuler
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000503:physiopathology*; D001714:Bipolar Disorder / Q000453:epidemiology / Q000503:physiopathology*; D015897:Comorbidity; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D014793:Visual Cortex / Q000503:physiopathology