EEG effects of smoking: Is there tachyphylaxis?

Smoking generally affects the human EEG by reducing low-frequency activity and increasing higher-frequency activity. Using a double-blind design, we sought to determine if acute tolerance (tachyphylaxis) to this effect can be observed. EEG was recorded in overnight-abstaining participants before and after smoking three cigarettes at 40-min intervals in two separate sessions. In one session ('short interval'), all three cigarettes had 'typical' nicotine yields (1.1 mg, FTC method). In the other session ('long interval'), the second cigarette had a very low nicotine yield (0.05 mg; thus making the interval between 1.1-mg cigarettes 80 min). Eyes-closed alpha power decreased and eyes-open beta-2 power increased following smoking each of the 'typical-yield' cigarettes but not the low-yield cigarettes. The decrease in alpha power after smoking the 'typical-yield' cigarette at the 40- and 80-min intervals was less than that following the first cigarette of the day, indicating tachyphylaxis. In contrast, the increase in eyes-open beta-2 power did not differ among cigarettes regardless of the order or interval between 'typical-yield' cigarettes. EEG changes in other frequency bands produced by smoking the first cigarette of the day were not consistent across sessions, making interpretation in terms of tachyphylaxis somewhat problematic. Overall, lower-frequency alpha activity displayed patterns consistent with tachyphylaxis while beta-2 did not.