My son had a stutter for about a year when he was about 5 years old. It was during the time when my Mom, his Grandma, was going through treatment for cancer. They had a bell at the cancer center that patients ring when their treatment is complete. He went with her to ring that bell, which would have signified that she was all better to him, and then his stutter went away completely that day. It was 100% gone for about 15 years. Then it came back when he was about 20 years old. Hr has been struggling with it, sometimes more and sometimes less, for the past 2 years. I work in special education, and everyone I speak to about it is pretty perplexed about his circumstances as well, because it was 100% gone and then came back just as bad as when he was 5. His is obviously related to anxiety. The first time was my Mom's cancer, and I think his adult onset stutter is due to the stress of trying to figure out what he wants to do with his life as an adult. Maybe that is something you are dealing with? I don't know, but it is a possibility. The most common reason for a stutter to show up as an adult would be head trauma, but after what I see in my son I do believe it can be emotional and psychological trauma, even if the trauma is caused by internal pressure rather than an external traumatic event, especially in more sensitive people who are very self critical.