Abnormal white matter integrity and impairment of cognitive abilities in adolescent inhalant abusers

Inhalant abuse represents a major health problem especially among adolescents and young adults. However, less is known about white matter (WM) microstructure in adolescent inhalant abusers. In the present study, we used diffusion tensor imaging (DTI) to study WM changes in adolescent inhalant abusers compared with healthy controls. We also tested whether there was any relationship between WM integrity and neuropsychological measures in adolescent inhalant abusers. The study included 19 adolescent inhalant abusers and 19 healthy control subjects. Whole brain analysis of WM microstructure was performed using tract-based spatial statistics (TBSS) to detect abnormal WM regions between groups. Wisconsin card sorting test (WCST) and Stroop test were used to measure neuropsychological performance. We found that adolescent inhalant abuser group had significantly higher axial diffusivity (AD) values in left parietal, occipital and temporal WM than in healthy control group. Inhalant abuser and control groups did not differ significantly on fractional anisotropy (FA) and radial diffusivity (RD) values. Adolescent inhalant abusers showed worse performance when compared with control group in WCST and Stroop test. There was no significant correlation of AD values in significant clusters with neuropsychological test performances within the two groups. We only found discrete impairments in neuropsychological test performance and WM integrity in adolescent inhalant abusers compared with healthy control subjects and we were not able to demonstrate a direct correlation between WM alterations and neurocognitive performance. Future work is required to longitudinally evaluate brain abnormalities through methods assessing brain structure, function and connectivity.