I'm hoping this belongs here, as it is a question about the underlying theory of personality traits. I am a long time cat owner and first time dog owner, thus am reading books to increase my understanding of canine behavior based on the most recent science available. My kid's dog who I am trying to train has been labeled as anxious by the vet and some behaviorists, but it doesn't really seem to fit. I found a short description of Impulsivity as a canine personality trait in the book "Making Dog Happy:..." by Paul McGreevy and Melissa Sterling, and honestly it seems like that is a more exact description for some of his personality. Yes, he does have anxiety, but that certainly is not precise enough nor descriptive enough to work with.

So I would like to hear from experts; what separates the traits of being reactive vs. impulsive vs. anxious. I am interested in hearing both theoretical and practical explanations, but would appreciate a label before each so I know which category the explanation fits in. I am assuming there is some overlap (as there is with many human traits and psychological issues), thus is anyone wants to actually point out those areas of overlap, that information would also be useful.