preoccupied about, preoccupied by, preoccupied with

Preoccupied is not necessarily followed by a preposition. When it is, preoccupied with is more common than preoccupied by or about.

• Because Canadians were preoccupied with health care, other issues took a back seat during the campaign.
• Cory was so preoccupied (or preoccupied by the news) that he forgot to make the phone call.
• The prison warden was preoccupied about the increasing level of infectious diseases.