I was a serious drug addict for at least 7 years. Started with cigs and alcohol at 16 and worked up to heroin and cocaine at 18. That lasted until I was 35. Bottom line, Marijuana is low on the scale. Should be done at home and don't do anything complicated or you run the chance of hurting yourself or someone else. Alcohol is down right deadly except in moderation. If you drink more everyday you have a problem. Heroin, Coke, X, Pills, Speed and crank should be avoided at all cost. These will seriously affect your thinking much less your physical health. Here's the shocker, cigarettes are the most addictive. I've been off hard drugs and alcohol for 10 years now but I just stopped smoking 3 weeks ago. It was the hardest thing I've ever done. 29 years of smoking! It was a bitch to stop. The key is moderation if you want to use anything addictive. That goes for food, drugs, and even pc games! Don't use drugs, life is great if you just stop and experience the new! Not preaching, just a heads up.