Does marijuana produce serotonin?

My girlfriend tells me she uses marijuana to calm herself if she is having a stressful day. She has been doing this for many years. She says smoking pot is like self-medicating — it is better than using anti-depressants. She also claims smoking pot helps with depression because of how it helps produce serotonin in the body. What is serotonin and how does it help depression? Does smoking pot really help with managing your anxiety, depression, etc.?


Are other drinks besides water still hydrating?

I frequently hear that beverages with caffeine or alcohol are not good for replenishing fluids and preventing dehydration. But in reality aren't they just a bit less effective at hydrating your body than other beverages? In other words, if you were stuck in the desert with nothing to drink but beer, coffee and cola, would you actually be worse off and die of thirst sooner if you drank these beverages versus not drinking anything at all?