Chunk #15 — 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
relevant is that antidepressants might cause chronic insomnia that would worsen mood. Smoking does appear to worsen sleep and, this does appear to be due to nicotine (Haro & Drucker-Colin 2004; Htoo et al. 2004). In addition, several studies have shown that chronic sleep problems can worsen mood (Colrain et al. 2004). Although nicotine given during withdrawal can improve insomnia (Colrain et al. 2004), insomnia is more prevalent with nicotine agonists (Silagy et al. 2004; Greenland et al. 1998; Society for Research on Nicotine and Tobacco 2007) and partial agonists (Cahill et al. 2007; Nides et al. 2006; Keating & Siddiqui 2006; Fagerstrom & Hughes 2007) than placebo in clinical trials. How often insomnia causes significant problems is unclear; e.g., there are no reports of how often smokers stop medications due to insomnia. The other possible mechanism relevant to nicotine medications is that antidepressants “energize” patients so they can act on suicidal ideation (Teicher et al. 1993). Nicotine is clearly a stimulant; however, its stimulant actions differ from those of prototypic stimulants such as the amphetamines (Clarke 1990), are mild, and typically decline as tolerance occurs (Clarke 1990). Finally, it is unclear whether any antidepressant effect of nicotine is via
