Psychedelics have definitely provided a step forward. They've opened completely new domains. Weed is not a sustainable alternative. I meditated for 2 hours a day for around 6 months last year, and it definitely helped my stutter. Normal people use the left brain hemisphere to talk (which is the neural region that processes language, whereas stutterers use the right hemisphere. The left and right hemisphere are bridged by the corpus callosum. In an optimal state, the two hemispheres are integrated and function as one unit. In our stuttering state, the right hemisphere 'interrupts' the left hemisphere. Meditation has been proven to integrate both hemispheres.