I think we all have multiple personality disorder, except that I wouldn't call it disorder. I wouldn't call it anything. It's just a characteristic of being human.
Some mornings I wake up and while singing Sondheim songs in the shower I think about stage moments from roles long past (in Bye Bye Birdie, How to Succeed, Sound of Music, et al) and leading man parts I still dream of playing.
Drawing a shot of espresso with perfect crema, I envision myself as a barista in a 100-square foot coffee bar just big enough for me and 2 or 3 of the regular customers whose lives I have become intimately familiar with since most of their days involve spending time with me.
Hosting friends for brunch and doing my best Martha Stewart impersonation (presentation really does matter) the names of the many restaurants and hotels I have thought of opening run through my mind.
Musical theatre star, barista, hospitality impresario—on any given day, these are just a few of the identities (in addition to the ones I currently embody) that I know would bring me much joy and satisfaction.
We owe it to ourselves (and others) to create space in our lives for the many aspects of our "self" that we want to authentically explore and experience.
Our multiple interests and personalities only become a disorder when we don't give them a home in our personal and professional lives. The opportunity (and the challenge) is to integrate and order our many part-time personalities into full-time fulfillment.