
Preoccupation
Interests and Hobbies
Use 'preoccupation' when referring to someone's hobbies or interests that take up a lot of their attention. 
Not Always Negative
'Preoccupation' doesn't always mean worry; it can be a neutral term for what occupies the mind. 
Professionally Used
It's appropriate to use 'preoccupation' in professional contexts to describe focus on work or projects. 