Talking to yourself (or even whispering) results in totally different neurological and physiological responses compared to talking in a social setting. Adrenaline and anxiety surges through the roof because the neurotransmitters in your brain surge and fire differently compared to talking to yourself in a quiet room without an audience listening. You cannot cure a chemical imbalance in your brain, you can only treat it with medication and ongoing psychotherapy, but your stutter will always be there because it’s neurological, not psychological.