My opinion is that a lot people who use any psycoactive drug multiple times a day tend to be a bit depressed or whatever anyway... and the drug gives them relief or comfort. And when they don't have the drug, more symptoms of their depression reveal themselves, since there is no drug hiding the symptoms of depression.

So, statistically, you might see a link between depression and frequent marijuana use or between depression and "withdrawl" after frequent MJ use. But I wouldn't necessarily say the marijuana (or the withdrawl from it) causes the depression as much as I would say the depression is there all the time, but the person uses marijauana most of the time to escape it.

I'm not saying everyone who uses MJ multiple times a day is depressed, because some people do just enjoy it so much they want to do it all the time. I'm just saying I bet a lot of people who do it all day everyday are a little depressed in their "sober" reality. Just like a lot of people who use valium or alcohol or whatever multiple times a day, every day, are likely a bit depressed in life.

I think it is healthiest to be sober enough to be able to and find peace, joy, and happiness in sober reality. Then one can use substances like beer, wine, cannabis, etc. in moderation now and again simply for the recreational value of the drugs. That is just my opinion.