Enlarged striatum in abstinent methamphetamine abusers: a possible compensatory response.
BACKGROUND
Little is known about structural brain abnormalities associated with methamphetamine (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-posterior corpus callosum (+ 9.7%, p = .05). Although METH users had normal cognitive function, those with smaller striatal structures had poorer cognitive performance and greater cumulative METH usage.


CONCLUSIONS
Since METH subjects with larger striatal structures had relatively normal cognitive performance and lesser cumulative METH usage, the enlarged putamen and globus pallidus might represent a compensatory response to maintain function. Possible mechanisms for the striatal enlargement include glial activation and inflammatory changes associated with METH-induced injury.
Chang
Linda
L
Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu 96813, USA. LChang@hawaii.edu
Cloak
Christine
C
Patterson
Kari
K
Grob
Charles
C
Miller
Eric N
EN
Ernst
Thomas
T
D000328:Adult; D019969:Amphetamine-Related Disorders / Q000473:pathology* / Q000503:physiopathology*; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008694:Methamphetamine; D008875:Middle Aged; D017072:Neostriatum / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology; D009483:Neuropsychological Tests; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012737:Sex Factors; D013223:Statistics as Topic; D014706:Verbal Learning / Q000502:physiology
D008694:Methamphetamine