ADDICTION

what is addiction ?  is marijuana addictive ? can somebody please define addiction its driving me crazy i need to know.

Addiction is :

" the state of being enslaved to a habit or practice or to something that is psychologically or physically habit-forming, as narcotics, to such an extent that its cessation causes severe trauma. "

so does this mean marijuana is addictive .? i am still unsure, the reason i ask is i think my brother and father are addicted and it makes me really angry . I try to suggest that they stay off it for atleast a week just to prove to them that they do not need the drug in there life , that maybe they could spend the money on more practicle things . But no i am shut down straight away for they can not go but a day without there hit of marijuana. I personally think it is stupid that they depend on this drug ,  that they choose to let this drug rule there life . They say i'm silly and i don't understand what its like to go without it but i have witnesed there behaiver while under the influence and i personally think they do not understand what it is like when they do smoke it . They tell me why am i getting so frustrated its not like they are hurting anyone but themsleves but i beg to differ , the behavier they display while stoned is not the type of behaviour you would expect from a role model whis is what they are Because they are in fact the eldest . My younger brother has just turned thirteen and he now thinks it is cool to smoke marijuana . Why .? Why must you set such a terrible example dad .? Josh (older brother) ? is it your wish that we all follow in your footsteps to let drugs rule our lifes,? do you want us to live a life where we cant pay our bills in time because we would rather buy drugs , not feed our kids because we would rather buy drugs.?  im just saying this is what your smoking drug infront of us could lead to .