A brain imaging study that looked at chronic users of codeine-containing cough syrups found deficits in specific regions of brain white matter and associates these changes with increased impulsivity in
codeine-containing cough syrup

 Codeine-containing cough syrups have become one of the most popular drugs of abuse in young people around the world and progressive changes in the white matter of users' brains may cause greater impulsivity in users, previous studies have found.

The researchers behind a new paper used diffusuion tensor imaging coupled with fractional anisotropy to investigate the white matter integrity of chronic cough syrup users. 

TBSS analysis of FA maps. Maps of thetvalue (P.05 corrected for multiple comparisons)
show, in red, the areas of significantly reduced FA in chronic codeine-containing cough syrup
users compared with controls.A, The frontal region of the right IFO. B, The temporo-occipital
region of the right IFO.C, The temporo-occipital region of left IFO. D, The right superior corona
radiata. Credit: doi: 10.3174/ajnr.A4070

Deficits were found in multiple regions of the brain, including the inferior fronto-occipital fasciculus, which other studies have found to be abnormal in other forms of addiction, such as addiction to the Internet, alcohol and heroin.

The study found the white matter deficits in users also correlated with increased impulsivity traits in the subjects, as measured by the Barratt Impulsiveness Scale. These findings were consistent with results of previous studies of heroin and cocaine addicts. White matter disruptions also correlated with the duration of
codeine-containing cough syrup

Citation: Y.-w. Qiu, H.-h. Su, X.-f. Lv and G.-h. Jiang, 'Abnormal White Matter Integrity in Chronic Users of Codeine-Containing Cough Syrups: A Tract-Based Spatial Statistics Study', American Journal of Neuroradiology, August 7, 2014 doi: 10.3174/ajnr.A4070. Source: American Society of Neuroradiology