<s>[INST] hi i am 20 yrs. old...i smoke nearly about 3 yrs...and i started smoking weed,hash nearly about one year..In the beginning i think it is not bad...But right now i feel the side effects of smoking these things...i lose concentration..reaction times become slow...how i build up my concentrations and overcome these sideeffects? [/INST] Thanks for your question on Chat Doctor. I can understand your concern. Honestly speaking, smoking is the worst habit for humans. It affects all organs of the body especially lungs, heart, liver, kidney etc. It also hampers brain functions So in my opinion, you should enroll yourself in dead diction center for smoking cessation. In dead diction center, they provide counseling sessions, motivational speech and Chat Doctor.  </s>