Modafinil improves working memory in healthy subjects and individuals diagnosed 
with schizophrenia and Attention Deficit/Hyperactivity Disorder, though the 
effects of modafinil have not been evaluated on working memory in 
methamphetamine-dependent subjects. This double-blind, placebo-controlled study 
evaluated whether a daily dose of 400 mg of modafinil, administered over three 
consecutive days, would enhance performance on a measure of working memory 
relative to test performance at baseline and following 3 days of placebo 
administration in 11 methamphetamine addicted, nontreatment-seeking volunteers. 
The results revealed that participants demonstrating relatively poor performance 
on the third day of a 3-day washout period (ie, at baseline), showed significant 
improvement on measures of working memory, but not on measures of episodic 
memory or information processing speed. In contrast, for participants 
demonstrating relatively high performance at baseline, modafinil administration 
did not affect test scores. The findings provide an initial indication that 
modafinil can reverse methamphetamine-associated impairments in working memory.