jack2206As a pharmacist, I can share with you some cited facts:
the bright side:
Nicotine Increases Brain Functional Network Efficiency and attentional performance (only on the short run, and need increasing dose to take effect). that's why it showed some benefits for patients with Alzheimer and Parkinson disease.
the dark side:
1-chronic exposure to nicotine or withdrawal from nicotine negatively affects the brain cognitive strategies to perform the memory task.
2- inhaled isolated nicotine (without tar or smoke) increases the risk of lung disease
3- nicotine is as addictive as heroin, cocaine or amphetamines, and for most people more addictive than alcohol.
4- statistical studies showed that 50% of smokers have mental health problems.
5- People exposed to secondhand smoke score 20% lower on memory tests
6- and a lot more
Nicotine, like many brain affecting drugs such as meth and even heroin, has positive cognitive and psychotropic benefits on the short run. However, it is like a bait that drags to the long run negative effects.
So, try to quit as early as possible.