(Late to the discussion.)
Marijuana is just a drug. Like any drug we humans have invented or discovered, it has both positive effects and negative effects.
The legal prescription drugs that your doctor doles out also have positive and negative effects.
I think the key is to know what you're getting in to.
BTW, I've never tried marijuana as I don't smoke and have no interest in smoking anything. NOT because it's illegal.
You can eat it.