I was on an venlafaxine for anxiety and depression for about 3 years, and in that time my stutter was still present, but it wasn't very severe. I stopped taking venlafaxine about 6 months ago, and I've definitely noticed an increase in my stuttering. I used to be able to hide it from people entirely, and now I stutter about every other sentence, or more if I'm nervous. I don't know if this is the case for others, but when I was taking medication it definitely reduced my stutter.