I was diagnosed with adult ADHD, a much overdue diagnosis.  I signed up for Mind Sparke training, which exercises your working memory to the point that you should be able to focus like a normal person, well almost.  It has been praised in the NY times.  It's competitor is called Cogmed, but is not as flexible and MUCH more expensive. 

This does not necessarily exclude Maladaptive Daydreaming.  They could coincide.  Maybe my daydreaming is a product of my ADHD inattentive…