A study looking at people with OCD has found an interesting link between guilt and OCD. It may be the sufferer's interpretation of their ability to cope with guilty feelings is connected to their behaviour. This study found that those with OCD may believe that they are unable to tolerate feelings of guilt and that it is this belief is what drives their maladaptive behaviours.
Taking this into account, treatment with clients with OCD would benefit from conversations with therapists about their beliefs about responsibility and teaching them tools to increase guilt tolerance in addition to helping modify their behaviours.
For more information you can check out a blog post describing the study in more detail.