Does Tobacco Addiction Affect Brain Functioning?

Hi, I am male age 27 yrs , residing in India. I have been consuming smokeless tobacco ( khaini ) from the past 5 yrs. Now I have realised that I am suffering from short term memory loss , now I am less excited doing all the things I used to do 5 yrs back , also I have realised that I have developed a habbit of speaking without thinking...and later I realise that I should not have said these words. I feel that I am suffering from a kind of brain problem..Also my mind is not as sharp as it used to be 5 yrs back ..Is it because of consuming smokeless tobacco ??

Please guide me as I have nobody to share what I have said above...