The site in the link you posted has some interesting points,but first let me fill you in...
I've been smoking weed for 26 years now,and i smoke about 5 joints a day..during that time i took good care of myself,healthy food and plenty of exercise...
I'm 39 years old and a thing like a deteriorating memory is just plain BS,when i'm stoned i can concentrate just as well as when i'm sober...but it could be personal.
Untill now i've never had any health problems related to the use of cannabis,if i would get problems i would quit right away,and i can cause i did quit for 3 months this year,and quited several times during those 26 years,just to test myself.
During those 3 months i felt good,but i missed lady MaryJane alot
so i gradually went back to smoking every day,and i feel good about it cause i know i can control it(haha to all of those that say you get addicted,again BS),but again thats personal,it requires some discipline..
I will admit that THC can build up in your brain,when i wake up i'm still a little hazed,more then when i go to sleep sober...but thats all,no hangovers,no headache and to be honest i like the hazy feeling in the morning!
I just have some simple rules,don't smoke while at work,dont smoke when i'm just awake,and don't smoke to get asleep,this will seriously have an impact on your life,cause you will get used to it and you feel even more hazy in the morning making it difficult to function..
But don't worry about losing your brain or memory,they are just stories to scare you off..especially dont trust British 'scientists',they are 25 years behind in research and have a government mission to scare the public,they spread pure lies!!
The only thing that can damage your brain is when you combine it with other things,like alcohol..so just try to keep that down a bit and you can safely smoke weed for a long time,i'm the living proof!!
Schizophrenia is triggered or worsened by its use, it may even be caused.
This only gets triggered if you have the genetic tendency for it,no genetic tendency,no schizofrenia...
Physical addiction occurs.
As to being physically addicted,again BS!!
But some mental addiction can occur,just remember discipline is all!Compare it to loving chocolade but not eating it every day...it's on that level so easily overcome.
If you want to quit:
Just dont quit at once,build your dosage off in a week and you will be fine..you could feel a little sweaty and restless but it dissappears after 2-3 days,i can assure you you will not be feeling 'reborn' or different,cause cannabis just doesnt affect you as much as other things do,quiting smoking tobacco is way harder!!usually people that feel physically addicted are actually addicted to the nicotine in the tobacco which they put in the joint..some way they combine these feelings and blame cannabis!