Before interviews i like to stay up all night (not that I want to) i have insomnia, but the more tired i am the less i stutter. Its like my mind takes the anxiety off speaking and focuses its energy elsewhere. I know this to be true because ive experimented with it in the past. When i take a sleeping pill and get a good nights rest i wake up energized but i stutter way much more than when im tired. Its a strange phenomenon for sure. Atleast for me.