What kind of health issues does it cause? Are you speaking from experience, (Of course not) Let's try to speak about what we have knowledge of and not speculate unless you disclose that it is just your opinion.
As a former ex-heavy user -- hey, it was the 60's/70's --, my recommendation is to do everything straight, sans pot or alcohol. I like a clear head now. But as someone who used to start the morning with a joint, I can see where at one time (if they had trading on the net back then), trading while high could be a lot of fun, especially on the long side in an abnormally bullish market. And as someone suggested before, I might even have wanted to try it on some of that excellent orange sunshine that I had in 1969. But really - 30 days is not a good sample size. At all. And getting high every day, in the morning especially, was a very bad idea for me.
in my culture, we smoke a lot of weed and it helps to calm and focus. i don't particularly smoke before trading, but i can see how it could be beneficial.
I smoke weed 30 minutes before market open and take some addy. I quit for the day when I make my goal. This is the only preparation I have mentally.
If you're going to have a drink or take a puff to take the edge off . Do it after work IMO. Work before play . Also, there is a difference between light use and abuse for any chemical. That being said, working out or physical activity is a better choice for stress relief. I like to do light exercise through the trading day. 25 curls, crunches, push ups, or squats every half hour or hour during the trading day. It helps get the endorphins going.
Cannabis has almost zero health risks. It doesn't cause cancer even if smoked chronically - in fact it might cure cancer. It doesn't kill brain cells. It isn't a gateway drug. It turns out that we have an endocannabinoid system. Endocannabinoids and their receptors are found throughout the body: in the brain, organs, connective tissues, glands, and immune cells. In each tissue, the cannabinoid system performs different tasks, but the goal is always the same: homeostasis, the maintenance of a stable internal environment despite fluctuations in the external environment. Now whether it will help someone as a trader is a different topic. I would imagine the trade off is less ability to focus but a greater ability to deal with stress. If smoking it makes you paranoid then it probably isn't going to help your trading at all. I'm in the camp with ZR1 - meditation and some exercise does more for me in terms of focus and calm than I think cannabis ever could. I did have a poker playing friend who played high limit games while doing what he called "suburban speedballs" - cannabis and espresso.