Reduced regional homogeneity in bilateral frontostriatal system relates to higher impulsivity behavior in codeine-containing cough syrups dependent individuals.
BACKGROUND
In the past twenty years, codeine-containing cough syrups (CCS) was recognized as a new type of addictive drugs. However, the exact neurobiologic mechanisms underlying CCS-dependence are still ill-defined. The aims of this study are to identify CCS-related modulations of neural activity during the resting-state in CCS-dependent individuals and to investigate whether these changes of neural activity can be related to duration of CCS use, the first age of CCS use and impulse control deficits in CCS-dependent individuals. We also want to observe the impact of gray matter deficits on these functional results.


RESULTS
Thirty CCS-dependent individuals and 30 control subjects participated. Resting-state functional MRI was performed by using gradient-echo echo-planar imaging sequence. Regional homogeneity (ReHo) was calculated by using REST software. Voxel-based analysis of the ReHo maps between controls and CCS-dependent groups was performed using two-sample t tests (p<0.05, corrected for multiple comparisons). The Barratt Impulsiveness Scale 11 (BIS.11) was surveyed to assess participants' impulsivity trait soon after MR examination. Abnormal clusters revealed by group comparison were extracted and correlated with impulsivity, duration of CCS use, and age of first CCS use. ReHo was diminished in the bilateral medial orbitofrontal cortex (mOFC) and left dorsal striatum in CCS-dependent individuals. There were negative correlations between mean ReHo in the bilateral medial OFC, left dorsal striatum and duration of CCS use, BIS.11 total scores, and the subscale of attentional impulsivity in CCS-dependent individuals. There was a significantly positive correlation between mean ReHo in the left dorsal striatum and age of first CCS use in CCS-dependent individuals. Importantly, these results still remain significant after statistically controlling for the regional gray matter deficits.


CONCLUSIONS
Resting-state abnormalities in CCS-dependent individuals revealed in the present study may further improve our understanding about the neural substrates of impulse control dysfunction in CCS-dependent individuals.
Department of Medical Imaging, Guangdong No. 2 Provincial People's Hospital, Guangzhou, P.R. China.
Yingwei
Y
Qiu
Xiaofei
X
Lv
Huanhuan
H
Su
Guihua
G
Jiang
Junzhang
J
Tian
Fuzhen
F
Zhuo
Lujun
L
Han
Xuelin
X
Zhang
D000328:Adult; D000996:Antitussive Agents / Q000009:adverse effects / Q000627:therapeutic use; D001931:Brain Mapping; D003061:Codeine / Q000009:adverse effects / Q000627:therapeutic use*; D003342:Corpus Striatum / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D003371:Cough / Q000188:drug therapy*; D005260:Female; D005625:Frontal Lobe / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007175:Impulsive Behavior / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D004366:Nonprescription Drugs / Q000009:adverse effects / Q000627:therapeutic use; D011446:Prospective Studies; D019966:Substance-Related Disorders / Q000503:physiopathology*; D055815:Young Adult
D000996:Antitussive Agents; D004366:Nonprescription Drugs; D003061:Codeine