What are the risks and benefits of smoking weed/marijuana?

The risks: are decrease in IQ and neuropsych testing decreased grey matter in the prefrontal cortex of the brain which are non-reversable, possible cardiac toxicity, and addiction. There are no actual benefits of smoking marijuana it only use is to "get high" there are other forms of thc containing medicines that are useful such as eye drops, and marinol for nausea and appetite stimulation.