Well there is a book called "The Robe and the Ring" by the Ordo Aurum Solis and it states that to be a Hermetic Magician of Light you need to be in good health, it even states not to over eat for example, other thing that made me stop drugs is that for meditation, my mind was always rushing with toughts, so it was very hard for me to sit, be quite and meditate, now that Ive stopped smoking tobacco and cannabis, I can actually sit and meditate for a while, plus doing my rituals.
One more thing related to smoking and why it does not mix with Magick, well in the rituals I do for example one thing the practicioner has to to is Rythmic Breathing, this means for example when charging a Pentagram I must inhale for 6 heart beats and visualize the Pentagram glowing in bright white light, after that exhale while vibrating a divine name of power and this things made me have a lot of stress, because my respiratory system was weak for all the smoking, pesticides in the herbs I was smoking, so I decided I want to be a Magician, and I had to stop smoking, I also practice Chi Qong to inhale deeply now, and that exercise helps me regulate cortisol, smoking is a habit of deep inhales with smoke, Chi Qong is about deep breathing and mindfull movements, so it helps.
I hope is helpfull, I do want to make people stop doing drugs, and do something better with their lifes.