In the past six months, I have known two people who have OD'd (and died) from legally prescribed prescription drugs. While that is above average, I have NEVER in my entire life known anyone who died of a marijuana overdose.
I believe the reason that statistics can be skewed to make it appear that addicts move from marijuana to harder drugs is precisely because it is illegal.
People buying pot have to buy from hardcore criminals who find it more profitable to get their customers hooked on drugs which are highly addictive than a relatively harmless drug like marijuana.
More people have died from cigarettes, alchohol & fast food than have ever died from marijuana.
Some of the hardest stuff out there is over the counter.
Marijuana is suspected to increase the risk of heart-attacks. I have know pot smokers who died young from heart attacks.
And the habitual pot smokers who haven't died just have lives that are go-nowhere zeros.
I love pot and smoked it for 20 years. But it does waste people's lives and definitely contributes to mental and emotional imbalances as well.