No, it is not the same thing at all. Possessing a knife or a gun does not tamper with the chemicals in your brain. It has no direct effect on your decision making processes.
WEll you are wrong there Bud, possessing a gun is a very powerful mind altering “drug” Having the power of life and death at you fingers? think about that. It is the personality that kills or abuses them selves. That does not mean that sane rational individuals should not have the right to utilize these things in a rational manner.