Over a period of 12 weeks , the improvement ( reduction ) in mean scores on the IRLS scale was greater , by 4.5 points , among participants receiving pregabalin than among those receiving placebo ( P < 0.001 ) , and the proportion of patients with symptoms that were very much improved or much improved was also greater with pregabalin than with placebo ( 71.4 % vs. 46.8 % , P < 0.001 ) .