Does nicotine do what we think it does? A meta-analytic review of the subjective effects of nicotine in nasal spray and intravenous studies with smokers and nonsmokers.
We conducted a meta-analysis of placebo-controlled laboratory studies of the subjective effects of nicotine. A total of 15 studies (11 with nasal spray, four with intravenous administration) with smokers and six studies (all with nasal spray) with never-smokers were included. Studies of other routes of administration (e.g., smoked tobacco) were not included because of insufficient numbers of available effect sizes. Meta-analysis results indicated that nicotine increased vigor for smokers but increased fatigue for never-smokers. Nicotine increased head rush for both smokers and never-smokers. In studies of smokers only, nicotine also increased ratings of drug high and drug liking. Contrary to expectations, nicotine decreased relaxation and increased tension/jitteriness for both smokers and never-smokers. Dose-response relationships were most clearly observed for head rush and drug high. Considerable variability was found across studies for a given nicotine dose and route of administration. Implications of the current findings about the role of subjective effects in nicotine reinforcement and self-administration are discussed along with commentary on methodological issues and recommendations for future studies.
Kalman
David
D
Boston University School of Medicine, MA, USA. david.kalman@med.va.gov
Smith
Stevens S
SS
D000281:Administration, Intranasal; D018849:Controlled Clinical Trials as Topic; D006801:Humans; D007275:Injections, Intravenous; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D010919:Placebos; D012907:Smoking / Q000503:physiopathology*
D010919:Placebos; D009538:Nicotine