Cortical folding in patients with bipolar disorder or unipolar depression.
BACKGROUND
Analysis of cortical folding may provide insight into neurodevelopment deviations, which, in turn, can predispose to depression that responds particularly poorly to medications. We hypothesized that patients with treatment-resistant depression would exhibit measurable alterations in cortical folding.


METHODS
We computed hemispheric global sulcal indices (g-SIs) in T(1)-weighted magnetic resonance images obtained from 76 patients and 70 healthy controls. We separately searched for anatomic deviations in patients with bipolar disorder (16 patients with treatment-resistant depression, 25 with euthymia) and unipolar depression (35 patients with treatment-resistant depression).


RESULTS
Compared with healthy controls, both groups of patients with treatment-resistant depression exhibited reduced g-SIs: in the right hemisphere among patients with bipolar disorder and in both hemispheres among those with unipolar depression. Patients with euthymic bipolar disorder did not differ significantly from depressed patients or healthy controls. Among patients with bipolar disorder who were taking lithium, we found positive correlations between current lithium dose and g-SIs in both hemispheres.


CONCLUSIONS
We cannot estimate the extent to which the observed g-SI reductions are linked to treatment resistance and to what extent they are state-dependent. Furthermore, we cannot disentangle the impact of medications from that of the affective disorder. Finally, there is interindividual variation and overlap of g-SIs among patients and healthy controls that need to be considered when interpreting our results.


CONCLUSIONS
Reduced global cortical folding surface appears to be characteristic of patients with treatment-resistant depression, either unipolar or bipolar. In patients with bipolar disorder, treatment with lithium may modify cortical folding surface.
Penttilä
Jani
J
INSERM, U797 Research Unit Neuroimaging & Psychiatry, CEA, Hospital Department Frédéric Joliot & Neurospin, Paris Sud University, Orsay, France.
Paillère-Martinot
Marie-Laure
ML
Martinot
Jean-Luc
JL
Ringuenet
Damien
D
Wessa
Michèle
M
Houenou
Josselin
J
Gallarda
Thierry
T
Bellivier
Frank
F
Galinowski
André
A
Bruguière
Pascale
P
Pinabel
François
F
Leboyer
Marion
M
Olié
Jean-Pierre
JP
Duchesnay
Edouard
E
Artiges
Eric
E
Mangin
Jean-François
JF
Cachia
Arnaud
A
D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D018692:Antimanic Agents / Q000627:therapeutic use; D001714:Bipolar Disorder / Q000188:drug therapy / Q000473:pathology* / Q000523:psychology; D002540:Cerebral Cortex / Q000473:pathology*; D003866:Depressive Disorder / Q000473:pathology* / Q000523:psychology; D004351:Drug Resistance; D004565:Electroconvulsive Therapy; D005260:Female; D007839:Functional Laterality; D006801:Humans; D016651:Lithium Carbonate / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales
D000928:Antidepressive Agents; D018692:Antimanic Agents; D016651:Lithium Carbonate