An experiment should have only one independent variable.
Armed victims are twice as likely to be killed by an assailant as unarmed victims. Because an armed person is most likely to be more dangerous than an armed person. If engaged in an action with an armed person they are most likely to be killed because they tend to fight back rather than surrender to the authorities.
Your immune system will fight off the bacteria .... maybe anti-biotics
All of the things that the other person has listed sounds more like crack. You don't really experience psychosis when smoking marijuana, you actually experience the exact opposite. Hallucinations don't occur unless weed was laced with acid or any other drug. The concentration, yeah. It is hard for me to concentrate when smoking until I'm baked, but not when I smoke just the right amount to the point where I'm calm and relaxed. Intense anxiety, fear, distrust, or panic is a load of BS. Weed has the exact opposite effects; it, again, makes you feel calm and relaxed and more happy about the world and that you're having the moment to relax and smoke a bowl. The THC DOES mess with your brain, so does any other drug or medication. You WILL NOT experience short term memory, but you MIGHT experience it. If I must say, I have only experienced it once or twice out of the 3 years of smoking weed. And yes, it may increase the risk of depression once you realize that you smoking weed causes your friends to leave you. Luckily, I don't have any friends, so that's not really a problem for me.
So there you have it, all of the negative effects proven wrong by an actual weed smoker instead of someone that goes with the stereotypes of how weed is perceived.