The effect of methamphetamine-induced neurodegeneration and psychiatric disorders on cognitive impairment in methamphetamine abusers in Thailand

Abstract

Methamphetamine  (METH)  has  been  found  to  be  one  of  the  leading  causes  of  neurotoxicity  in  the  brain  and psychosis. The present study aimed to investigate the interactive effect of METH on capacities for cognition. The higher  cognitive  functions  were  determined  in  METH  users  with  (n  =  16)  and  without  psychosis  (n  =  16)  and normal-control  subjects  (n =  16).

The results showed a significant decrease in the scores of Thai Mental State Examination and increase in Brief Psychiatric Rating Scale in METH users with psychotic symptoms compared with control subjects. Completed blood count  (CBC)  analysis  showed  a  significant  decrease  in  the  number  of  red  blood  cells,  the  levels  of  hemoglobin and  mean  corpuscular  hemoglobin  concentration  (MCHC)  but  a  significant  increase  in  the  number  of  basophils of  METH  users  without  psychotic  symptoms  compared  with  control  subjects.  The levels of low-grade systemic inflammatory biomarker, C-reactive proteins was significantly decreased in METH users with psychotic symptoms compared with control subjects. The higher cognitive functions was investigated using executive function (EF) tests including go/no-go task, one back task, Wisconsin Card Sorting Test and Stroop task. The METH users exhibited poor EF performance compared to controls such as attention, set shifting, working memory and speed of processing.

This  finding  may  emphasize  that  neurocognitive  deficits  associated  with  METH  abuse  may  result  from  some neurodegenerative  changes occurred in  the  brains.