Chunk #9 — 3. Results — 3.2 Association of Suicide with Current Smoking — 3.2.1. Possible Mechanisms — 3.2.1.2. Smoking as a Psychological or Physical Toxin
Smoking could cause suicides via several mechanisms. The first posits that smoking worsens mood, impulsivity, aggression and other behavioral factors that predispose to suicide (Parrott 2003). Typically, it is the nicotine in cigarettes that is thought to cause these behavioral problems (Parrott 2003). Several indirect lines of evidence support this explanation. For example, in cross-sectional studies, smokers report more negative affect than never-smokers or exsmokers (Parrott 2003). Similarly, long-term former smokers report less depression than current smokers or when they themselves used to smoke (US Department of Health and Human Services 1990b). Also, when nicotine is given intravenously in higher doses to never-smokers, this results in increased negative affect (Newhouse et al. 1988).
