My new patient explained that in her sophomore year at college she had started smoking. The effect, she said, was like “a key that fit perfectly into a lock.” Her brain felt clearer, her thoughts were more coherent, her mood and energy improved.
...I found her image of a key in a lock particularly striking; it was the very same one that psychiatrists and neurophysiologists use to describe the interactions in the brain between neurotransmitters and their receptors. And in fact, neurons do have receptors into which nicotine neatly fits, mimicking the actions of the brain’s own molecules.
...In other words, nicotine is like most of the medications I prescribe. Nearly all involve risks and in some, such as Ritalin, Adderall and other stimulants, many of the side effects are nearly identical to those of nicotine, including potential addiction. For some patients, a medication can lead to nearly miraculous improvements.
http://www.nytimes.com/2016/03/06/opinion/sunday/can-nicotine-be-good-for-you.html?&_r=0