The word 'fixated' implies an unhealthy level of attention on something, almost to the exclusion of others. She became so fixated on getting promotion that she neglected her health.
Pro Tip 2/3
Negative Connotation
'Fixated' often carries a negative connotation, suggesting the focus isn't positive or beneficial. Mark's fixated interest in conspiracy theories is starting to worry his friends.
Pro Tip 3/3
Current Relevance
Use 'fixated' to describe current, ongoing situations where the focus is active and persistent. Ever since the new policy was introduced, the committee has remained fixated on its potential drawbacks.