Experimental and Clinical Psychopharmacology 1999, Vol. 7. No. 4. 454-463 Copyright 1999 by the American Psychological Association, Inc. 1064-1297/99/$3.00 Nicotine Reduces the Frequency of Anger Reports in Smokers and Nonsmokers With High but Not Low Hostility: An Ambulatory Study Larry D. Jamner University of California, Irvine David Shapiro and Murray E. Jarvik University of California, Los Angeles Two studies were conducted to determine the anger-attenuating effects of nicotine as a function of trait hostility. The 1st study examined the effects of nicotine on diary ratings of anger during a 24-hr period in a natural setting in 30 smokers and 30 nonsmokers. Participants took part in 2 monitoring sessions involving the administration of a nicotine patch and a placebo patch. Participants were categorized as high or low on trait hostility on the basis of their scores on the Cook-Medley Hostility scale. Administration of the nicotine patch, compared with the placebo patch, resulted in a significant reduction in diary reports of anger from 24% to 13% in high-hostile participants. In low-hostile participants, nicotine had no effect on reports of anger during the day. The anger-palliative effects of nicotine were greatest among participants more frequently reporting anger on the placebo-patch day. These effects were independent of smoking status and gender. The 2nd study, which was restricted to high-hostile smokers (n = 19) and nonsmokers (n = 23), found that, compared with a placebo patch, administration of nicotine resulted in significant reductions in reports of anger in smokers and nonsmokers. The results of these 2 studies clearly link nicotine to reduced reports of anger in high-hostile individuals. On reviewing the literature on why people smoke, Gilbert (1995) hypothesized that smoking promotes fewer negative thoughts and moods as well as enhanced concentration and more positive affect. Negative affect modulation has been considered a major underlying motivation for smoking (Eysenck, 1973; Leventhal & Cleary, 1980; Tomkins, 1968), although smokers differ greatly in how nicotine affects their behavioral and affective responses (Gilbert, 1994; Tomkins, 1968). In animal studies, nicotine has been shown to attenuate aggressive behaviors in cats (Berntson, Beattie, & Walker, 1976) and to suppress provoked fighting in rats and mon- keys, and these effects have been shown to be dose- dependent and independent of any nonspecific depressant effects of nicotine (Driscoll & Baettig, 1981; Emley & Hutchinson, 1983; Rodgers, 1979; Silverman, 1971; Waldbil- lig, 1980). Parallel findings have been reported in studies of Larry D. Jamner, Department of Psychology and Social Behav- ior, University of California, Irvine; David Shapiro and Murray E. Jarvik, Department of Psychiatry and Biobehavioral Sciences, School of Medicine, University of California, Los Angeles. Portions of this article were presented at the Fourth International Congress of Behavioral Medicine, Washington, DC, March 1996. This research was supported by Grant 1RO1-NS-34143 from the National Institute of Neurological Disorders and Stroke and by Research Grant 6RT0154 from the University of California, Tobacco-Related Disease Research Program. We thank Dina Raduechel, Mindy Hightower, and Rachelle Soles for their assistance with data collection and management and Shane Ricketts for his help with data editing. Correspondence concerning this article should be addressed to Larry D. Jamner, Department of Psychology and Social Behavior, School of Social Ecology, 3340 Social Ecology II, University of California, Irvine, California 92697-7085. Electronic mail may be sent to ljamner@uci.edu. humans (Cherek, 1981; Cherek, Bennett, & Grabowski, 1991). Cherek et al. examined the aggressive responses of 8 healthy male heavy smokers under conditions of ad-lib smoking, nicotine gum, placebo gum, or no gum. Compared with the ad-lib condition, aggressive responding was higher with placebo gum and highest in the no-gum condition. Having smokers chew two pieces of nicotine polacrilex gum (2 mg) for 30 min before the experiment reduced aggressive responding to levels comparable to ad-lib cigarette smoking. Cigarette smoking has been shown to reduce anger, irrita- tion, and aggression in deprived habitual smokers but only when they are placed in anger-provoking or irritating situations (Acri & Grunberg, 1992; Schechter & Rand, 1974). Although the mechanism by which nicotine sup- presses aggressivity is not completely understood, the results of several of these studies point to a selective central nicotinic cholinergic receptor agonism (Emley & Hutchin- son, 1983; Rodgers, 1979; Waldbillig, 1980). Dispositional and situational variables also play a role in determining nicotine's affect-modulatory effects (Gilbert, 1995). Little is known about the acute effects of nicotine, or smoking as a function of dispositional hostility. Trait hostility has consistently predicted higher smoking rates in several large-scale cross-sectional and longitudinal studies (Lipkus, Barefoot, Williams, & Siegler, 1994; Scherwitz et al., 1992; Shekelle, Gale, Ostfeld, & Oglesby, 1983; Siegler, Peterson, Barefoot, & Williams, 1992), although this relation- ship has not been observed in all studies (Houston & Vavak, 1991). In a longitudinal study of more than 4,700 individuals (Lipkus et al., 1994), high-hostile college students were more likely than low-hostile college students to subse- quently take up smoking and still be smokers 20 years later. Hostile individuals experience anger frequently and in- tensely (Houston & Vavak, 1991). Shapiro, Jamner, and 454