Does add cause difficulty focusing on every tasks including those of personal interest?

Yes: Adult add is probably underdiagnosed. Nobody focuses easily on stuff they hate or find boring; the add sufferer has trouble focusing on play and the things they like. The real question is, "will add medication help me?" some of my colleagues recommend a therapeutic trial. Good luck.

Variable: Some children and adults with adhd are not only able to focus on a task of personal interest to them but actually become "overfocused, " blocking out any and all stimuli except the task at hand--in adults this sometimes is called "spousal deafness." however, they typically are still vulnerable to distraction if they take a break and something else of interest pops up.