When the problem is beneath the surface in OCD: the cognitive treatment of a case of pure mental contamination

Mental contamination is a phenomenon whereby people experience feelings of contamination from a non-physical contaminant. Rachman (2006) proposes that standard cognitive behavioural treatments (CBT) need to be adapted here and there is a developing empirical grounding supporting the concept, although suggestions on adapting treatment have yet to be tested.

A single case study is presented of a man with a 20-year history of severe treatment resistant Obsessive Compulsive Disorder (OCD) characterized by mental contamination following the experience of "betrayal". He was offered two consecutive treatments: standard CBT and then (following disengagement with this) a cognitive therapy variant adapted for mental contamination. Clinician and patient rated OCD severity was measured at baseline and the start and end of both interventions.

Six sessions of high quality CBT were initially attended before refusal to engage with further sessions. There were no changes in OCD severity ratings across these sessions. A second course of cognitive therapy adapted for mental contamination was then offered and all 14 sessions and follow-ups were attended. OCD severity fell from the severe to non-clinical range across these sessions.

The need to consider adapting standard treatments for mental contamination is suggested. Limitations and implications are discussed.