Can quitting smoking cause intrusive thoughts?

ISmoking can: But these are typically related to the act of smoking or ones self perceived will power. When in doubt seek councilng to assist with the process ( at the very least)

It can uncover them: To the extent that smoking served to distract you when you felt anxiety (or other things), not smoking could leave the field open for those thoughts. Also, nicotine has a chemical structure that's similar to transmitters that are calming and not having them might also allow the thoughts to increase in power. Try CBT therapy for skills in managing them. Best!