A 26-year-old primary school teacher, presents to you with extreme distress. She says that her life is badly affected and she has intrusive thoughts that she recognises as senseless. She is forced to check the class room lock frequently and and hence leaves the school very late. She worries that she has left something impoant inside. She has similar problems with food checking and checking the envelops before send out any posts. At present she follows a strict set of routines for most routine activities. All of the following are good long term treatment options for Leela, EXCEPT: