Preoccupation (noun)

1. The state of being preoccupied; the state of having one's attention, thoughts or feelings engaged with something.
2. An excessive focus or worry about a particular thing.

Origin:

From the french préoccupation, from pré- ("before") + occupation ("occupatio.n")

Examples:

1. His preoccupation with work left him little time for his family.
2. Her preoccupation with her appearance was causing her anxiety.
3. The company's preoccupation with profits led to neglect of their social responsibilities.
4. His preoccupation with conspiracy theories made it difficult for him to trust others.
5. The government's preoccupation with national security led to a restriction of civil liberties.