揭祕:戒菸困難背後的原因
Why is smoking so difficult to give up? Inhaling a puff of smoke from a cigarette sends nicotine molecules zooming up into the brain within seconds. Then the nicotine grabs hold of receptors on brain cells and releases dopamine, the brain's feel-good chemical, bringing feelings of pleasure and comfort。
Besides dopamine, smoking also activates the release of other molecules in the brain that make you feel good, including chemicals called endogenous opioids, according to 2004 research from the University of Michigan。
And cigarette companies haven't been making it any easier for people to kick the habit. Over the past decade, companies have made changes to the design and ingredients in cigarettes to make them more alluring to first-time smokers, and more addictive for long-time smokers。
These changes include adding ammonia to the tobacco, which converts nicotine into a form that gets to the brain faster, as well as adding holes to cigarette filters that allow people to inhale smoke more deeply into their lungs. Other additions, such as sugar and "moisture enhancers," reduce the dry, burning sensation of smoking, making it a more pleasant experience - especially for new cigarette smokers。
When you stop smoking, and your nicotine receptors stop being activated. Essentially, you're not getting as much dopamine as you're used to, which can cause feelings of withdrawal. In fact, a 2002 study in the Journal of Consulting and Clinical Psychology showed that people who had quit cold turkey had lingering feelings of depression and tension 31 days later。
美國“生命無祕密”網站10日報道：爲什麼戒菸如此困難？吸一口煙能在幾秒鐘內迅速將微小的尼古丁顆粒送進大腦。隨後尼古丁控制了腦細胞受體，並釋放出多巴胺——大腦中感覺良好的化學成分，能給人帶來愉悅和舒適的感覺。
除了多巴胺，吸菸還能促發大腦中使人感覺良好的其他微小顆粒的釋放，包括被稱爲內源性類鴉片活性肽的化學分子，密歇根大學2004年的研究表明。
此外，菸草公司也沒有使人們更容易戒除吸菸。在過去10年，菸草公司改變了香菸的設計和成分，使它們對第一次吸菸的人更有吸引力，使長期吸菸的人更容易上癮。
變化包括在菸草中加入氨，它將尼古丁變成一種更快達到大腦的形式，並增加了菸嘴中的孔，這使人們能將煙更深地吸入肺部。其他改變包括加入糖和溼潤劑，這樣減少了吸菸時的乾燥和焦灼感，使吸菸成爲更愉悅的經歷——尤其是對新菸民而言。
在你停止吸菸時，你的尼古丁受體不再被啓動，因而你無法得到你習慣得到的那麼多多巴胺。這會引起退縮的感覺。實際上，《諮詢與臨牀心理學》雜誌2002年刊載的一項研究顯示，那些突然完全停止使用毒品的人在31天后仍有抑鬱和緊張的感覺。
