When you've got mental worries and you're high, you may not be worried but you're not solving anything either. When you've got worries and you knit, you bang out a sock in a week.
Drunks usually give you their opinion whether you want it or not. Knitters usually just become fascinated with their yo,K3tog,yo rhythm. In my case, this is a good thing, because so often what I'm thinking is definitely not something that should be shared if harmony is desired. It also creates a buffer of time, you don't just leap into the fray, you wait until you've reached a good point in the chart to put the project down. By then, the urge may have passed, or you've rethunk it.
When drugs are your choice, you tend to stick to only a small menu. When you're done with a knitting fix, there's a wide field of possibilities for your next toke/pipeful. And there's no problem if someone asks you to pee in a cup. You've probably needed to go for an hour but kept doing "just one more row."