25/06/2013

"Withdrawal" effect in smokers

- For years scientists have discussed the "withdrawal" effect in smokers - the phenomenon that smokers themselves describe as "concentration difficulty" when they have not smoked for several hours. In the anti-smoking lobby it is believed that the phenomenon is a simple abstinence effect that smokers can lift by smoking a cigarette again, and thereby return to the same level of performance as "normal people". 

But this theory no longer holds true after the Heishman analysis. Nicotine in itself creates better performance compared to placebo, whether smokers or non-smokers. But there are scientists who do not believe that the "withdrawal" effect has been proven. 

One of them is nicotine researcher, Professor David Warburton of Reading University, who in a double experiment in 1994 first demonstrated that 100 "abstinent" smokers and 100 non-smokers achieved similar results in three specific figures tests. In experiment no. 2 he repeated the same three tests with only the smokers who were divided into two groups - one that had been "abstinent" for 12 hours, while the second group had smoked one hour earlier: Improvements in performance without nicotine withdrawal . 

Both groups were divided into two subgroups, one receiving regular cigarettes, while the other had fake cigarettes. In one task, participants were told to enter the correct numbers in a certain sequence in 20 minutes - and after the first five minutes they should light up a cigarette and take one puff every minute. The results are shown here: 
Figure 1 - Warburton & Arnall, 1994: - The scale shows the number of correct answers, minute by minute. Participants smoked one puff per minute in the period between the dotted lines, from the 6. minute to the 15. minute. The two top lines are the results for nicotine groups - the bottom two are from non-nicotine groups. Each group consisted of one abstinent group & one non-abstinent group.

Result: The number of correct answers rose in the two nicotine groups with approx. 30% from the third cigarette puff. There was, however, no difference in responses between the "abstinent" and the non-abstinent participants. The two nicotine groups had also significantly 10-15% faster reaction time, (not shown in graph).

- The Warburton trial shows specifically that cigarettes' effect on attention and response time is particularly strong in the ten minutes during which the actual smoking takes place, and in the following minutes. 

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