What happens when you smoke? [Disadvantages]

One of the unfamiliar disadvantages you get when you smoke is Depression..!  Might be shocking.

Generally humans do not meet their daily need of intake of water. (root cause for digestive troubles or ulcers)
As you already know, while you smoke, you will get acid secreted in your digestive track. (you might get few small burps while smoking or within few minutes, due to acidity)

when both the above combines, you get acid in you digestive system without food or water, which leads to damaging of your digestive track internal walls. (better take a liquid while smoking, like tea or coffee or water)

Due to above wall damage, your nutrition absorption declines, leading to unhealthy level of nutrients, which leads to mental and physical tiredness. Actually the first to inform you about lack of nutrition is your brain. You will start getting a slight but different awkward kind of head aches in severe cases.

If the above continues for a period of time, for sure you will get the 'so called chemical imbalance'.

Symptoms:

   You cannot think or focus as you were before.

   Your productivity declines, you might feel postpone of tasks.

   You cannot easily smile or laugh naturally.

Note: All the content expressed above are just my own views on my experience.