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 El Tabaco          Industria Tabacalera  Derechos de los
No Fumadores
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Efectos físicos y psicológicos Tomado del Taller de Capacitación para ONGs sobre Ratificación del CONVENIO MARCO PARA CONTROL DE TABACO de la Fundación Interamericana del Corazón
ABC of smoking cessation
Why people smoke Martin J Jarvis  Physical and psychological effects of nicotine
Absorption of cigarette smoke from the lung is rapid and complete,
producing with each inhalation a high concentration arterial bolus
of nicotine that reaches the brain within 10-16 seconds, faster than
by intravenous injection. Nicotine has a distributional half life of
15-20 minutes and a terminal half life in blood of two hours.
Smokers therefore experience a pattern Nicotine has pervasive effects on brain neurochemistry. It activates nicotinic acetylcholine receptors (nAchRs), which are widely distributed in the brain, and induces the release of dopamine in the nucleus accumbens. This effect is the same as that produced by other drugs of misuse (such as amphetamines and cocaine) and is thought to be a critical feature of brain addiction mechanisms. Nicotine is a psychomotor stimulant, and in new users it speeds simple reaction time and improves performance on tasks of sustained attention. However, tolerance to many of these effects soon develops, and chronic users probably do not continue to obtain absolute improvements in performance, cognitive processing, or mood. Smokers typically report that cigarettes calm them down when they are stressed and help them to concentrate and work more effectively, but little evidence exists that nicotine provides effective self medication for adverse mood states or for coping with stress. A plausible explanation for why smokers perceive cigarettes to be calming may come from a consideration of the effects of nicotine withdrawal. Smokers start to experience impairment of mood and performance within hours of their last cigarette, and certainly overnight. These effects are completely alleviated by smoking a cigarette. Smokers go through this process thousands of times over the course of their smoking career, and this may lead them to identify cigarettes as effective self medication, even if the effect is the negative one of withdrawal relief rather than any absolute improvement. Symptoms of nicotine withdrawal Much of the intractability of cigarette smoking is thought to stem from the problems of withdrawal symptoms—particularly irritability, restlessness, feeling miserable, impaired concentration, and increased appetite—as well as from cravings for cigarettes. These withdrawal symptoms begin within hours of the last cigarette and are at maximal intensity for the first week. Most of the affective symptoms then resolve over three or four weeks, but hunger can persist for several months. Cravings, sometimes intense, can also persist for many months, especially if triggered by situational cues. Effects of nicotine withdrawal
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