Great question. Smoking effects every part of your body, especially your brain. Actually, it not only effects your brain, the nicotine physically changes your brain.
I wrote a blog/SHARE about this exact question (called "Mind Over Matter"). You can read it here: https://www.empowher.com/node/2629/subscribe
Let me know if you have any follow up questions or need more specific information, and I'm glad to try to answer!