The selected examples of successful dosaging ranges are provided, while emphasizing the necessity of empirically determined dose-response relationships based on the precise parameters and conditions inherent to a specific hypothesis. This review provides a new, experimentally based compilation of species-specific dose selection for studies on the in vivo effects of nicotine.

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Although both the human and animal literatures are notable for the general lack of attention paid to possible sex differences in drug self-administration behavior, evidence is accumulating to suggest that males and females may differ in factors that maintain tobacco smoking or nicotine self-administration. Self-administration of nicotine per se may be less robust in women, and women are less sensitive than men to some effects of nicotine that may be reinforcing. Compared to men, smoking behavior of women may be influenced more by non-nicotine stimuli associated with smoking, suggesting greater conditioned reinforcement of smoking in women. Moreover, nicotine replacement, the current standard treatment for smoking cessation, is sometimes less effective in women, further suggesting the need for greater consideration of non-nicotine factors that may maintain women's smoking. Very recent research on rats also indicates sex differences in nicotine self-administration. However, these differences are complex and suggest that nicotine-seeking behavior is composed of several components, including hedonic, incentive-motivational, and conditioning effects; males and females may differ in one or more of these components. Menstrual or estrous cycle phase effects on the maintenance of nicotine self-administration are not particularly apparent in humans or animals, although cycle phase may influence other stages of dependence (e.g., withdrawal symptoms during cessation). Future research should evaluate further the consistency of results across human and non-human species, identify the conditions and procedures under which sex differences are observed, and elucidate the specific components of reinforcement that may differ between males and females. Studies also should examine the possible generalizability of these sex differences to other drugs of abuse. Identification of specific factors responsible for these sex differences may lead to improved interventions for smoking cessation and other substance abuse in women.

This article reviews short-term (6 months) and longer term (12-24 months) maintenance of cessation and relapse in adult smokers and the factors and treatments that affect these outcomes. MedLine and PsycLIT searches were done for research published in English between 1988 and 1998 meeting a defined set of criteria. Intensive intervention, telephone counseling, and use of pharmacotherapy were found to improve outcomes; however, compared with public health approaches, they reach relatively few smokers. Brief interventions during medical visits are cost-effective and could potentially reach most smokers but are not consistently delivered. Predictors of relapse include slips, younger age, nicotine dependence, low self-efficacy, weight concerns, and previous quit attempts. Potential areas for research, recommendations for longer follow-up assessments, and standard definitions for slip, relapse, and long-term maintenance are discussed.

An inability to maintain abstinence is a key indicator of tobacco dependence. Unfortunately, little evidence exists regarding the ability of the major tobacco dependence measures to predict smoking cessation outcome. This paper used data from four placebo-controlled smoking cessation trials and one international epidemiologic study to determine relations between the Fagerström Test for Nicotine Dependence (FTND; Heatherton et al., 1991), the Heaviness of Smoking Index (HSI; Kozlowski et al., 1994), the Nicotine Dependence Syndrome Scale (NDSS; Shiffman et al., 2004) and the Wisconsin Inventory of Smoking Dependence Motives (WISDM; Piper et al. 2004) with cessation success. Results showed that much of the predictive validity of the FTND could be attributed to its first item, time to first cigarette in the morning, and this item had greater validity than any other single measure. Thus, the time to first cigarette item appears to tap a pattern of heavy, uninterrupted, and automatic smoking and may be a good single-item measure of nicotine dependence.