Enlarged striatum in abstinent methamphetamine abusers: A possible compensatory response

Background Little is known about structural brain abnormalities associated with methampbetamine (METH) abuse, therefore, we aimed: 1) to evaluate possible morphometric changes, especially in the striatum of recently abstinent METH-dependent subjects,- 2) to evaluate whether morphometric changes are related to cognitive performance; and 3) to determine whether there are sex-by-METH interactions on morphometry. Methods. Structural MRI was performed in 50 METH and 50 comparison subjects with the same age range and sex proportion; quantitative morphometric analyses were performed in the subcortical gray matter, cerebellum and corpus callosum. Neuropsychological tests were also performed in 44 METH and 28 comparison subjects. Results: METH users showed enlarged putamen (left: + 10.3%, p =.0007; right.- + 9.6%, p =.001) and globus pallidus (left. + 9.3%, p =.002,- right.. + 6.6%, p =.01). Female METH subjects additionally showed larger mid-poster or corpus callosum (+ 9.7%, p =.05). Although METH users bad normal cognitive function, those with smaller striatal structures bad poorer cognitive performance and greater cumulative METH usage. Conclusions: Since METH subjects with larger striatal structures bad relatively normal cognitive performance and lesser cumulative METH usage, the enlarged putamen and globus pallidus might represent a compensatory response to maintain Junction. Possible mechanisms for the striatal enlargement include glial activation and inflammatory changes associated with METH-induced injury.