It had no effect on the mean ( SD ) frequency of urges to smoke at 1 week after the TQD , their strength , or the severity of withdrawal symptoms : these ratings for varenicline vs placebo were 2.7 ( 1.1 ) vs 2.6 ( 0.9 ) ( P = .90 ) , 2.6 ( 1.1 ) vs 2.8 ( 1.0 ) ( P = .36 ) , and 1.5 ( 0.4 ) vs 1.6 ( 0.5 ) ( P = .30 ) , respectively .