presents the demographic characteristics of the sample. Smokers consumed an average of 20 cigarettes (one pack) per day (SD = 6.3) for 16 years (SD = 9.8). They also showed moderate nicotine dependence, with an average score on the Fagerström Test for Nicotine Dependence of 5.3 (SD = 2.5).
Characteristics of Participantsa
Measures of Negative Symptoms and Cigarette Craving
presents the mean expired CO levels, and mean scores on the UTS and SJWS scales, recorded at the beginning of each test session on each test day. Seven smokers did not have complete data in all four test sessions; therefore, data from 44 smokers were used in the analyses. Transformations applied to the CO levels and SJWS subscale scores helped approximate normal distributions. Repeated measures ANOVAs assessed the effects of test day, session, and their interactions. The UTS data were not normally distributed, and transformations could not bring the distributions to normal. Therefore, Wilcoxon signed-ranks matched-pairs tests assessed the significance of these data.
Measures of Expired CO, Negative Symptoms, and Craving in Smokers a
There was a significant interaction between test day and test session on the expired CO data (F
(1, 41) = 76.83, p = .000, η2= .84). Smokers abstinent overnight exhibited lower CO levels before Test Session 1 and greater increases in CO levels from Test Session 1 to Test Session 2 (when smoking one cigarette occurred) than briefly abstinent (15–60 min) smokers. Data from the SJWS indicated a significant interaction between test day and test session on each of the five subscales (all p’s < 0.001). Smokers abstinent 13–16 h exhibited higher scores in the first session of the day, indicating more severe negative symptoms and craving than briefly abstinent smokers. Scores decreased considerably after resuming smoking on the day of overnight abstinence, but increased slightly on the day of brief abstinence from smoking (craving, F(1, 41) = 53.14, p < .001, η2= .56; psychological, F(1, 41) = 36.18, p < .001, η2= .47; physical, F(1, 41) = 128.40, p < .001, η2= .76; appetite, F(1, 41) = 166.58, p < .001, η2= .80). During the first session of the Brief Abstinence day, scores on the sedation subscale were lower than in the first session of the Overnight Abstinence day, and after resuming smoking on both days, scores increased (F(1, 41) = 83.07, p < .001, η2= .67). The UTS data also revealed a significant interaction between test day and test session (z = −3.86, p < .001) with higher scores on the day of overnight abstinence than the day of brief abstinence, indicating greater smoking urges, and a greater reduction in scores after resuming smoking on the day of overnight abstinence than the day of brief abstinence.
The Effect of Smoking Abstinence
Analysis of the response time data for smokers in the first test session on each test day combined revealed a main effect of stimuli (F(1, 50) = 22.02, p < 0.001, η2 = .31), indicating that smokers had significantly longer response times to smoking-related than to neutral words (mean = 805 ms, SE = 18.4; and mean = 770 ms, SE = 16.8, respectively) (see ). Analysis of these data revealed a main effect of abstinence (collapsing the data across stimulus type, mean = 802, SE = 09.0, and = 773 ms, SE = 17.8, respectively; F(1, 50) = 4.87, p =.03, η2 = .09), indicating that smokers had significantly longer response times after overnight abstinence than after brief abstinence from smoking. All results presented in are significant. However, there was no significant interaction between test day (Brief Abstinence and Overnight Abstinence) and stimulus type (F(1, 50) = .002, p =.96) on performance in the session before the break, confirming that overnight abstinence did not create differential attention bias; rather it increased overall response time.
Response Times: Effect of Resumption of Smoking
The Effect of Resuming Smoking
Analysis of the response time data comparing Test Sessions 1 and 2 from the Overnight Abstinence test day indicated a main effect of stimulus type (F(1, 50) = 15.98, p < .001, η2 = .24; smoking-related mean = 768 ms, SE = 17.27; neutral mean = 799 ms, SE = 19.38) and a main effect of Test Session (F(1, 50) = 13.55, p < .001, η2 = .21; Session 1 mean = 802 ms, SE = 19.01; and Session 2 mean = 765 ms, SE = 18.18), but no significant interaction between the two variables (F(1, 50) = .33, p = .56). Analysis of the response time data comparing Test Sessions 1 and 2 from the Briefly abstinence test day indicated a main effect of stimulus type (F(1, 50) = 27.47, p < .001, η2 = .35; smoking-related mean = 777 ms, SE = 19.33; neutral mean = 743 ms, SE = 17.54) and a main effect of Test Session (F(1, 50) = 5.25, p < .05, η2 = .09; Session 1 mean = 773, SE = 17.90; Session 2 mean = 748, SE = 20.01), but no significant interaction between the two variables (F(1, 50) = .04, p = .84).